Structures which are part of the CELL MEMBRANE or have cell membrane as a major part of their structure.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.
Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.
Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
Artificially produced membranes, such as semipermeable membranes used in artificial kidney dialysis (RENAL DIALYSIS), monomolecular and bimolecular membranes used as models to simulate biological CELL MEMBRANES. These membranes are also used in the process of GUIDED TISSUE REGENERATION.
The motion of phospholipid molecules within the lipid bilayer, dependent on the classes of phospholipids present, their fatty acid composition and degree of unsaturation of the acyl chains, the cholesterol concentration, and temperature.
A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
Preparation for electron microscopy of minute replicas of exposed surfaces of the cell which have been ruptured in the frozen state. The specimen is frozen, then cleaved under high vacuum at the same temperature. The exposed surface is shadowed with carbon and platinum and coated with carbon to obtain a carbon replica.
A darkly stained mat-like EXTRACELLULAR MATRIX (ECM) that separates cell layers, such as EPITHELIUM from ENDOTHELIUM or a layer of CONNECTIVE TISSUE. The ECM layer that supports an overlying EPITHELIUM or ENDOTHELIUM is called basal lamina. Basement membrane (BM) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. BM, composed mainly of TYPE IV COLLAGEN; glycoprotein LAMININ; and PROTEOGLYCAN, provides barriers as well as channels between interacting cell layers.
Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.
The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a choline moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and choline and 2 moles of fatty acids.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Established cell cultures that have the potential to propagate indefinitely.
A fluorescent compound that emits light only in specific configurations in certain lipid media. It is used as a tool in the study of membrane lipids.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.
A replica technique in which cells are frozen to a very low temperature and cracked with a knife blade to expose the interior surfaces of the cells or cell membranes. The cracked cell surfaces are then freeze-dried to expose their constituents. The surfaces are now ready for shadowing to be viewed using an electron microscope. This method differs from freeze-fracturing in that no cryoprotectant is used and, thus, allows for the sublimation of water during the freeze-drying process to etch the surfaces.
Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.
Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.
Glycoproteins found on the membrane or surface of cells.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A system of cisternae in the CYTOPLASM of many cells. In places the endoplasmic reticulum is continuous with the plasma membrane (CELL MEMBRANE) or outer membrane of the nuclear envelope. If the outer surfaces of the endoplasmic reticulum membranes are coated with ribosomes, the endoplasmic reticulum is said to be rough-surfaced (ENDOPLASMIC RETICULUM, ROUGH); otherwise it is said to be smooth-surfaced (ENDOPLASMIC RETICULUM, SMOOTH). (King & Stansfield, A Dictionary of Genetics, 4th ed)
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
Transport proteins that carry specific substances in the blood or across cell membranes.
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.
A stack of flattened vesicles that functions in posttranslational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)
The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.
Single membrane vesicles, generally made of PHOSPHOLIPIDS.
Measurement of the polarization of fluorescent light from solutions or microscopic specimens. It is used to provide information concerning molecular size, shape, and conformation, molecular anisotropy, electronic energy transfer, molecular interaction, including dye and coenzyme binding, and the antigen-antibody reaction.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Components of a cell.
Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.
A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.

Scavenger receptor BI transfers major lipoprotein-associated phospholipids into the cells. (1/160)

The phospholipids of lipoproteins can be transferred to cells by an endocytosis-independent uptake pathway. We analyzed the role of scavenger receptor BI (SR-BI) for the selective cellular phospholipid import. Human monocytes rapidly acquired the pyrene (py)-labeled phospholipids sphingomyelin (SM), phosphatidylcholine, and phosphatidylethanolamine from different donors (low and high density lipoproteins (LDL, HDL), lipid vesicles). The anti-SR-BI antibody directed against the extracellular loop of the membrane protein lowered the cellular import of the phospholipids by 40-80%. The phospholipid transfer from the lipid vesicles into the monocytes was suppressed by LDL, HDL, and apoprotein AI. Transfection of BHK cells with the cDNA for human SR-BI enhanced the cellular import of the vesicle-derived py-phospholipids by 5-6-fold. In the case of the LDL donors, transfer of py-SM to the transfected cells was stimulated to a greater extent than the uptake of the other py-phospholipids. Similar differences were not observed when the vesicles and HDL were used as phospholipid donors. The concentration of LDL required for the half-maximal phospholipid import was close to the previously reported apparent dissociation constant for LDL binding to SR-BI. The low activation energy of the SR-BI-mediated py-phospholipid import indicated that the transfer occurs entirely in a hydrophobic environment. Disruption of cell membrane caveolae by cyclodextrin treatment reduced the SR-BI-catalyzed incorporation of py-SM, suggesting that intact caveolae are necessary for the phospholipid uptake. In conclusion, SR-BI mediates the selective import of the major lipoprotein-associated phospholipids into the cells, the transfer efficiency being dependent on the structure of the donor lipoprotein.  (+info)

Myosin-X, a novel myosin with pleckstrin homology domains, associates with regions of dynamic actin. (2/160)

Myosin-X is the founding member of a novel class of unconventional myosins characterized by a tail domain containing multiple pleckstrin homology domains. We report here the full-length cDNA sequences of human and bovine myosin-X as well as the first characterization of this protein's distribution and biochemical properties. The 235 kDa myosin-X contains a head domain with <45% protein sequence identity to other myosins, three IQ motifs, and a predicted stalk of coiled coil. Like several other unconventional myosins and a plant kinesin, myosin-X contains both a myosin tail homology 4 (MyTH4) domain and a FERM (band 4.1/ezrin/radixin/moesin) domain. The unique tail domain also includes three pleckstrin homology domains, which have been implicated in phosphatidylinositol phospholipid signaling, and three PEST sites, which may allow cleavage of the myosin tail. Most intriguingly, myosin-X in cultured cells is present at the edges of lamellipodia, membrane ruffles, and the tips of filopodial actin bundles. The tail domain structure, biochemical features, and localization of myosin-X suggest that this novel unconventional myosin plays a role in regions of dynamic actin.  (+info)

Coordinated gating of TRP-dependent channels in rhabdomeral membranes from Drosophila retinas. (3/160)

Using a newly developed dissociation procedure, we isolated the specialized rhabdomeral membranes from Drosophila retinal photoreceptors. From these membranes, we have recorded spontaneous active currents in excised patch, voltage-clamp recordings. We observed rapid opening events that closely resembled those ascribed to one class of light-activated channels, TRP. All activity exhibited Ba(2+) permeability, little voltage dependence, and sensitivity to La(3+) block. Mutational analysis indicated that the spontaneous activity present in these membranes was TRP-dependent. Excised patches from wild-type rhabdomeral membranes exhibited a wide range of conductance amplitudes. In addition, large conductance events exhibited many conductance levels in the open state. Block of activity by La(3+) both developed and recovered in a stepwise manner. Our results indicate that TRP-dependent channels have a small unitary conductance and that many channels can be gated coordinately.  (+info)

p(1),p(4)-diadenosine 5'-tetraphosphate induces the uptake of arginine and citrulline by a pore on the plasma membrane of bovine aortic endothelial cells. (4/160)

We have previously demonstrated that p(1),p(4)-diadenosine 5'-tetraphosphate (Ap(4)A) induces the release of nitric oxide (NO) and modulates the uptake of extracellular L-arginine (L-Arg) and L-citrulline (L-Cit) by bovine aortic endothelial cells (BAEC) [Hilderman, R.H. and Christensen, E.F. (1998) FEBS Lett. 427, 320-324 and Hilderman, R.H., Casey, T.E. and Pojoga, L.H. (2000) Arch. Biochem. Biophys. 375, 124-130]. In this communication we report that extracellular Ap(4)A enhances the uptake of L-Arg and L-Cit through a pore on the plasma membrane of BAEC that is selective for these two amino acids. We also demonstrate that Ap(2)A, which induces NO release, enhances L-Arg uptake while Ap(5)A, a vasoconstrictor, does not enhance the uptake of L-Arg. The potential physiological significance of the uptake of these two amino acids in relation to NO synthesis is discussed.  (+info)

The yeast inositol polyphosphate 5-phosphatases inp52p and inp53p translocate to actin patches following hyperosmotic stress: mechanism for regulating phosphatidylinositol 4,5-bisphosphate at plasma membrane invaginations. (5/160)

The Saccharomyces cerevisiae inositol polyphosphate 5-phosphatases (Inp51p, Inp52p, and Inp53p) each contain an N-terminal Sac1 domain, followed by a 5-phosphatase domain and a C-terminal proline-rich domain. Disruption of any two of these 5-phosphatases results in abnormal vacuolar and plasma membrane morphology. We have cloned and characterized the Sac1-containing 5-phosphatases Inp52p and Inp53p. Purified recombinant Inp52p lacking the Sac1 domain hydrolyzed phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P(2)] and PtdIns(3, 5)P(2). Inp52p and Inp53p were expressed in yeast as N-terminal fusion proteins with green fluorescent protein (GFP). In resting cells recombinant GFP-tagged 5-phosphatases were expressed diffusely throughout the cell but were excluded from the nucleus. Following hyperosmotic stress the GFP-tagged 5-phosphatases rapidly and transiently associated with actin patches, independent of actin, in both the mother and daughter cells of budding yeast as demonstrated by colocalization with rhodamine phalloidin. Both the Sac1 domain and proline-rich domains were able to independently mediate translocation of Inp52p to actin patches, following hyperosmotic stress, while the Inp53p proline-rich domain alone was sufficient for stress-mediated localization. Overexpression of Inp52p or Inp53p, but not catalytically inactive Inp52p, which lacked PtdIns(4,5)P(2) 5-phosphatase activity, resulted in a dramatic reduction in the repolarization time of actin patches following hyperosmotic stress. We propose that the osmotic-stress-induced translocation of Inp52p and Inp53p results in the localized regulation of PtdIns(3,5)P(2) and PtdIns(4,5)P(2) at actin patches and associated plasma membrane invaginations. This may provide a mechanism for regulating actin polymerization and cell growth as an acute adaptive response to hyperosmotic stress.  (+info)

Restricted accumulation of phosphatidylinositol 3-kinase products in a plasmalemmal subdomain during Fc gamma receptor-mediated phagocytosis. (6/160)

Phagocytosis is a highly localized and rapid event, requiring the generation of spatially and temporally restricted signals. Because phosphatidylinositol 3-kinase (PI3K) plays an important role in the innate immune response, we studied the generation and distribution of 3' phosphoinositides (3'PIs) in macrophages during the course of phagocytosis. The presence of 3'PI was monitored noninvasively in cells transfected with chimeras of green fluorescent protein and the pleckstrin homology domain of either Akt, Btk, or Gab1. Although virtually undetectable in unstimulated cells, 3'PI rapidly accumulated at sites of phagocytosis. This accumulation was sharply restricted to the phagosomal cup, with little 3'PI detectable in the immediately adjacent areas of the plasmalemma. Measurements of fluorescence recovery after photobleaching were made to estimate the mobility of lipids in the cytosolic monolayer of the phagosomal membrane. Stimulation of phagocytic receptors induced a marked reduction of lipid mobility that likely contributes to the restricted distribution of 3'PI at the cup. 3'PI accumulation during phagocytosis was transient, terminating shortly after sealing of the phagosomal vacuole. Two factors contribute to the rapid disappearance of 3'PI: the dissociation of the type I PI3K from the phagosomal membrane and the persistent accumulation of phosphoinositide phosphatases.  (+info)

Differential dynamics of alpha 5 integrin, paxillin, and alpha-actinin during formation and disassembly of adhesions in migrating cells. (7/160)

To investigate the mechanisms by which adhesions form and disperse in migrating cells, we expressed alpha 5 integrin, alpha-actinin, and paxillin as green fluorescent protein (GFP) fusions. All localized with their endogenous counterparts and did not perturb migration when expressed at moderate levels. alpha 5-GFP also rescued the adhesive defects in CHO B2 cells, which are alpha 5 integrin deficient. In ruffling cells, alpha 5-GFP and alpha-actinin--GFP localized prominently at the leading edge in membrane protrusions. Of the three GFP fusion proteins that we examined, paxillin was the first component to appear visibly organized in protrusive regions of the cell. When a new protrusion formed, the paxillin appeared to remodel from older to newer adhesions at the leading edge. alpha-Actinin subsequently entered adhesions, which translocated toward the cell center, and inhibited paxillin turnover. The new adhesions formed from small foci of alpha-actinin--GFP and paxillin-GFP, which grew in size. Subsequently, alpha 5 integrin entered the adhesions to form visible complexes, which served to stabilize the adhesions. alpha 5-GFP also resided in endocytic vesicles that emanated from the leading edge of protrusions. Integrin vesicles at the cell rear moved toward the cell body. As cells migrated, alpha 5 vesicles also moved from a perinuclear region to the base of the lamellipodium. The alpha 5 vesicles colocalized with transferrin receptor and FM 4-64 dye. After adhesions broke down in the rear, alpha 5-GFP was found in fibrous structures behind the cell, whereas alpha-actinin--GFP and paxillin-GFP moved up the lateral edge of retracting cells as organized structures and then dissipated.  (+info)

The Dictyostelium CARMIL protein links capping protein and the Arp2/3 complex to type I myosins through their SH3 domains. (8/160)

Fusion proteins containing the Src homology (SH)3 domains of Dictyostelium myosin IB (myoB) and IC (myoC) bind a 116-kD protein (p116), plus nine other proteins identified as the seven member Arp2/3 complex, and the alpha and beta subunits of capping protein. Immunoprecipitation reactions indicate that myoB and myoC form a complex with p116, Arp2/3, and capping protein in vivo, that the myosins bind to p116 through their SH3 domains, and that capping protein and the Arp2/3 complex in turn bind to p116. Cloning of p116 reveals a protein dominated by leucine-rich repeats and proline-rich sequences, and indicates that it is a homologue of Acan 125. Studies using p116 fusion proteins confirm the location of the myosin I SH3 domain binding site, implicate NH(2)-terminal sequences in binding capping protein, and show that a region containing a short sequence found in several G-actin binding proteins, as well as an acidic stretch, can activate Arp2/3-dependent actin nucleation. p116 localizes along with the Arp2/3 complex, myoB, and myoC in dynamic actin-rich cellular extensions, including the leading edge of cells undergoing chemotactic migration, and dorsal, cup-like, macropinocytic extensions. Cells lacking p116 exhibit a striking defect in the formation of these macropinocytic structures, a concomitant reduction in the rate of fluid phase pinocytosis, a significant decrease in the efficiency of chemotactic aggregation, and a decrease in cellular F-actin content. These results identify a complex that links key players in the nucleation and termination of actin filament assembly with a ubiquitous barbed end-directed motor, indicate that the protein responsible for the formation of this complex is physiologically important, and suggest that previously reported myosin I mutant phenotypes in Dictyostelium may be due, at least in part, to defects in the assembly state of actin. We propose that p116 and Acan 125, along with homologues identified in Caenorhabditis elegans, Drosophila, mouse, and man, be named CARMIL proteins, for capping protein, Arp2/3, and myosin I linker.  (+info)

A cell membrane, also known as the plasma membrane, is a thin, flexible barrier that surrounds every cell in an organism. It is composed of two layers of phospholipid molecules, which have both hydrophilic (water-attracting) and hydrophobic (water-repelling) properties. This unique structure allows the cell membrane to selectively control the movement of materials into and out of the cell.

The cell membrane is composed of several different types of molecules, including proteins, carbohydrates, and lipids. These molecules are organized into various structures that perform specific functions:

1. Phospholipid bilayer: The main component of the cell membrane is a double layer of phospholipid molecules. Each phospholipid molecule has a hydrophilic head and two hydrophobic tails. The heads face outwards, towards the watery environment inside and outside the cell, while the tails face inwards, creating a hydrophobic barrier that is difficult for most polar molecules to cross.
2. Integral proteins: These proteins are embedded within the phospholipid bilayer and can span all or part of the membrane. They play various roles, such as serving as channels or pumps for the transport of molecules across the membrane, acting as receptors for hormones and other signaling molecules, and providing structural support to the membrane.
3. Peripheral proteins: These proteins are associated with the outer or inner surface of the cell membrane but do not span its entire thickness. They can perform various functions, such as participating in cell-cell recognition, anchoring the cytoskeleton to the membrane, and acting as enzymes that catalyze chemical reactions.
4. Glycolipids: These are lipid molecules with a carbohydrate group attached to them. They are found on the outer surface of the cell membrane and play a role in cell-cell recognition and adhesion.
5. Glycoproteins: These are proteins with carbohydrate groups attached to them. Like glycolipids, they are found on the outer surface of the cell membrane and contribute to cell-cell recognition and adhesion.
6. Membrane microdomains (rafts): These are small, highly organized regions of the cell membrane that contain a high concentration of cholesterol and sphingolipids. They provide a platform for various cellular processes, such as signal transduction, membrane trafficking, and protein sorting.
7. Membrane asymmetry: The inner and outer leaflets of the cell membrane have different lipid compositions. For example, phosphatidylserine is primarily located in the inner leaflet, while sphingomyelin and glycosphingolipids are enriched in the outer leaflet. This asymmetry plays a role in various cellular processes, such as blood clotting and apoptosis (programmed cell death).

The complex structure of the cell membrane allows it to perform its many functions, including maintaining cell shape, providing a barrier between the inside and outside of the cell, regulating the movement of molecules across the membrane, and participating in various signaling pathways.

A cell membrane, also known as the plasma membrane, is a thin semi-permeable phospholipid bilayer that surrounds all cells in animals, plants, and microorganisms. It functions as a barrier to control the movement of substances in and out of the cell, allowing necessary molecules such as nutrients, oxygen, and signaling molecules to enter while keeping out harmful substances and waste products. The cell membrane is composed mainly of phospholipids, which have hydrophilic (water-loving) heads and hydrophobic (water-fearing) tails. This unique structure allows the membrane to be flexible and fluid, yet selectively permeable. Additionally, various proteins are embedded in the membrane that serve as channels, pumps, receptors, and enzymes, contributing to the cell's overall functionality and communication with its environment.

Membrane lipids are the main component of biological membranes, forming a lipid bilayer in which various cellular processes take place. These lipids include phospholipids, glycolipids, and cholesterol. Phospholipids are the most abundant type, consisting of a hydrophilic head (containing a phosphate group) and two hydrophobic tails (composed of fatty acid chains). Glycolipids contain a sugar group attached to the lipid molecule. Cholesterol helps regulate membrane fluidity and permeability. Together, these lipids create a selectively permeable barrier that separates cells from their environment and organelles within cells.

In medical terms, membranes refer to thin layers of tissue that cover or line various structures in the body. They are composed of connective tissue and epithelial cells, and they can be found lining the outer surface of the body, internal organs, blood vessels, and nerves. There are several types of membranes in the human body, including:

1. Serous Membranes: These membranes line the inside of body cavities and cover the organs contained within them. They produce a lubricating fluid that reduces friction between the organ and the cavity wall. Examples include the pleura (lungs), pericardium (heart), and peritoneum (abdominal cavity).
2. Mucous Membranes: These membranes line the respiratory, gastrointestinal, and genitourinary tracts, as well as the inner surface of the eyelids and the nasal passages. They produce mucus to trap particles, bacteria, and other substances, which helps protect the body from infection.
3. Synovial Membranes: These membranes line the joint cavities and produce synovial fluid, which lubricates the joints and allows for smooth movement.
4. Meninges: These are three layers of membranes that cover and protect the brain and spinal cord. They include the dura mater (outermost layer), arachnoid mater (middle layer), and pia mater (innermost layer).
5. Amniotic Membrane: This is a thin, transparent membrane that surrounds and protects the fetus during pregnancy. It produces amniotic fluid, which provides a cushion for the developing baby and helps regulate its temperature.

Intracellular membranes refer to the membrane structures that exist within a eukaryotic cell (excluding bacteria and archaea, which are prokaryotic and do not have intracellular membranes). These membranes compartmentalize the cell, creating distinct organelles or functional regions with specific roles in various cellular processes.

Major types of intracellular membranes include:

1. Nuclear membrane (nuclear envelope): A double-membraned structure that surrounds and protects the genetic material within the nucleus. It consists of an outer and inner membrane, perforated by nuclear pores that regulate the transport of molecules between the nucleus and cytoplasm.
2. Endoplasmic reticulum (ER): An extensive network of interconnected tubules and sacs that serve as a major site for protein folding, modification, and lipid synthesis. The ER has two types: rough ER (with ribosomes on its surface) and smooth ER (without ribosomes).
3. Golgi apparatus/Golgi complex: A series of stacked membrane-bound compartments that process, sort, and modify proteins and lipids before they are transported to their final destinations within the cell or secreted out of the cell.
4. Lysosomes: Membrane-bound organelles containing hydrolytic enzymes for breaking down various biomolecules (proteins, carbohydrates, lipids, and nucleic acids) in the process called autophagy or from outside the cell via endocytosis.
5. Peroxisomes: Single-membrane organelles involved in various metabolic processes, such as fatty acid oxidation and detoxification of harmful substances like hydrogen peroxide.
6. Vacuoles: Membrane-bound compartments that store and transport various molecules, including nutrients, waste products, and enzymes. Plant cells have a large central vacuole for maintaining turgor pressure and storing metabolites.
7. Mitochondria: Double-membraned organelles responsible for generating energy (ATP) through oxidative phosphorylation and other metabolic processes, such as the citric acid cycle and fatty acid synthesis.
8. Chloroplasts: Double-membraned organelles found in plant cells that convert light energy into chemical energy during photosynthesis, producing oxygen and organic compounds (glucose) from carbon dioxide and water.
9. Endoplasmic reticulum (ER): A network of interconnected membrane-bound tubules involved in protein folding, modification, and transport; it is divided into two types: rough ER (with ribosomes on the surface) and smooth ER (without ribosomes).
10. Nucleus: Double-membraned organelle containing genetic material (DNA) and associated proteins involved in replication, transcription, RNA processing, and DNA repair. The nuclear membrane separates the nucleoplasm from the cytoplasm and contains nuclear pores for transporting molecules between the two compartments.

Artificial membranes are synthetic or man-made materials that possess properties similar to natural biological membranes, such as selective permeability and barrier functions. These membranes can be designed to control the movement of molecules, ions, or cells across them, making them useful in various medical and biotechnological applications.

Examples of artificial membranes include:

1. Dialysis membranes: Used in hemodialysis for patients with renal failure, these semi-permeable membranes filter waste products and excess fluids from the blood while retaining essential proteins and cells.
2. Hemofiltration membranes: Utilized in extracorporeal circuits to remove larger molecules, such as cytokines or inflammatory mediators, from the blood during critical illnesses or sepsis.
3. Drug delivery systems: Artificial membranes can be used to encapsulate drugs, allowing for controlled release and targeted drug delivery in specific tissues or cells.
4. Tissue engineering: Synthetic membranes serve as scaffolds for cell growth and tissue regeneration, guiding the formation of new functional tissues.
5. Biosensors: Artificial membranes can be integrated into biosensing devices to selectively detect and quantify biomolecules, such as proteins or nucleic acids, in diagnostic applications.
6. Microfluidics: Artificial membranes are used in microfluidic systems for lab-on-a-chip applications, enabling the manipulation and analysis of small volumes of fluids for various medical and biological purposes.

Membrane fluidity, in the context of cell biology, refers to the ability of the phospholipid bilayer that makes up the cell membrane to change its structure and organization in response to various factors. The membrane is not a static structure but rather a dynamic one, with its lipids constantly moving and changing position.

Membrane fluidity is determined by the fatty acid composition of the phospholipids that make up the bilayer. Lipids with unsaturated fatty acids have kinks in their hydrocarbon chains, which prevent them from packing closely together and increase membrane fluidity. In contrast, lipids with saturated fatty acids can pack closely together, reducing membrane fluidity.

Membrane fluidity is important for various cellular processes, including the movement of proteins within the membrane, the fusion of vesicles with the membrane during exocytosis and endocytosis, and the ability of the membrane to respond to changes in temperature and other environmental factors. Abnormalities in membrane fluidity have been linked to various diseases, including cancer, neurological disorders, and infectious diseases.

Cell membrane permeability refers to the ability of various substances, such as molecules and ions, to pass through the cell membrane. The cell membrane, also known as the plasma membrane, is a thin, flexible barrier that surrounds all cells, controlling what enters and leaves the cell. Its primary function is to protect the cell's internal environment and maintain homeostasis.

The permeability of the cell membrane depends on its structure, which consists of a phospholipid bilayer interspersed with proteins. The hydrophilic (water-loving) heads of the phospholipids face outward, while the hydrophobic (water-fearing) tails face inward, creating a barrier that is generally impermeable to large, polar, or charged molecules.

However, specific proteins within the membrane, called channels and transporters, allow certain substances to cross the membrane. Channels are protein structures that span the membrane and provide a pore for ions or small uncharged molecules to pass through. Transporters, on the other hand, are proteins that bind to specific molecules and facilitate their movement across the membrane, often using energy in the form of ATP.

The permeability of the cell membrane can be influenced by various factors, such as temperature, pH, and the presence of certain chemicals or drugs. Changes in permeability can have significant consequences for the cell's function and survival, as they can disrupt ion balances, nutrient uptake, waste removal, and signal transduction.

An erythrocyte, also known as a red blood cell, is a type of cell that circulates in the blood and is responsible for transporting oxygen throughout the body. The erythrocyte membrane refers to the thin, flexible barrier that surrounds the erythrocyte and helps to maintain its shape and stability.

The erythrocyte membrane is composed of a lipid bilayer, which contains various proteins and carbohydrates. These components help to regulate the movement of molecules into and out of the erythrocyte, as well as provide structural support and protection for the cell.

The main lipids found in the erythrocyte membrane are phospholipids and cholesterol, which are arranged in a bilayer structure with the hydrophilic (water-loving) heads facing outward and the hydrophobic (water-fearing) tails facing inward. This arrangement helps to maintain the integrity of the membrane and prevent the leakage of cellular components.

The proteins found in the erythrocyte membrane include integral proteins, which span the entire width of the membrane, and peripheral proteins, which are attached to the inner or outer surface of the membrane. These proteins play a variety of roles, such as transporting molecules across the membrane, maintaining the shape of the erythrocyte, and interacting with other cells and proteins in the body.

The carbohydrates found in the erythrocyte membrane are attached to the outer surface of the membrane and help to identify the cell as part of the body's own immune system. They also play a role in cell-cell recognition and adhesion.

Overall, the erythrocyte membrane is a complex and dynamic structure that plays a critical role in maintaining the function and integrity of red blood cells.

Membrane potential is the electrical potential difference across a cell membrane, typically for excitable cells such as nerve and muscle cells. It is the difference in electric charge between the inside and outside of a cell, created by the selective permeability of the cell membrane to different ions. The resting membrane potential of a typical animal cell is around -70 mV, with the interior being negative relative to the exterior. This potential is generated and maintained by the active transport of ions across the membrane, primarily through the action of the sodium-potassium pump. Membrane potentials play a crucial role in many physiological processes, including the transmission of nerve impulses and the contraction of muscle cells.

A lipid bilayer is a thin membrane made up of two layers of lipid molecules, primarily phospholipids. The hydrophilic (water-loving) heads of the lipids face outwards, coming into contact with watery environments on both sides, while the hydrophobic (water-fearing) tails point inward, away from the aqueous surroundings. This unique structure allows lipid bilayers to form a stable barrier that controls the movement of molecules and ions in and out of cells and organelles, thus playing a crucial role in maintaining cellular compartmentalization and homeostasis.

Electron microscopy (EM) is a type of microscopy that uses a beam of electrons to create an image of the sample being examined, resulting in much higher magnification and resolution than light microscopy. There are several types of electron microscopy, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), and reflection electron microscopy (REM).

In TEM, a beam of electrons is transmitted through a thin slice of the sample, and the electrons that pass through the sample are focused to form an image. This technique can provide detailed information about the internal structure of cells, viruses, and other biological specimens, as well as the composition and structure of materials at the atomic level.

In SEM, a beam of electrons is scanned across the surface of the sample, and the electrons that are scattered back from the surface are detected to create an image. This technique can provide information about the topography and composition of surfaces, as well as the structure of materials at the microscopic level.

REM is a variation of SEM in which the beam of electrons is reflected off the surface of the sample, rather than scattered back from it. This technique can provide information about the surface chemistry and composition of materials.

Electron microscopy has a wide range of applications in biology, medicine, and materials science, including the study of cellular structure and function, disease diagnosis, and the development of new materials and technologies.

Freeze fracturing is not a medical term itself, but it is a technique used in the field of electron microscopy, which is a type of imaging commonly used in scientific research and medical fields to visualize structures at a very small scale, such as cells and cellular components.

In freeze fracturing, a sample is rapidly frozen to preserve its structure and then fractured or split along a plane of weakness, often along the membrane of a cell. The freshly exposed surface is then shadowed with a thin layer of metal, such as platinum or gold, to create a replica of the surface. This replica can then be examined using an electron microscope to reveal details about the structure and organization of the sample at the molecular level.

Freeze fracturing is particularly useful for studying membrane structures, such as lipid bilayers and protein complexes, because it allows researchers to visualize these structures in their native state, without the need for staining or other chemical treatments that can alter or damage the samples.

The basement membrane is a thin, specialized layer of extracellular matrix that provides structural support and separates epithelial cells (which line the outer surfaces of organs and blood vessels) from connective tissue. It is composed of two main layers: the basal lamina, which is produced by the epithelial cells, and the reticular lamina, which is produced by the connective tissue. The basement membrane plays important roles in cell adhesion, migration, differentiation, and survival.

The basal lamina is composed mainly of type IV collagen, laminins, nidogens, and proteoglycans, while the reticular lamina contains type III collagen, fibronectin, and other matrix proteins. The basement membrane also contains a variety of growth factors and cytokines that can influence cell behavior.

Defects in the composition or organization of the basement membrane can lead to various diseases, including kidney disease, eye disease, and skin blistering disorders.

Liposomes are artificially prepared, small, spherical vesicles composed of one or more lipid bilayers that enclose an aqueous compartment. They can encapsulate both hydrophilic and hydrophobic drugs, making them useful for drug delivery applications in the medical field. The lipid bilayer structure of liposomes is similar to that of biological membranes, which allows them to merge with and deliver their contents into cells. This property makes liposomes a valuable tool in delivering drugs directly to targeted sites within the body, improving drug efficacy while minimizing side effects.

Protein transport, in the context of cellular biology, refers to the process by which proteins are actively moved from one location to another within or between cells. This is a crucial mechanism for maintaining proper cell function and regulation.

Intracellular protein transport involves the movement of proteins within a single cell. Proteins can be transported across membranes (such as the nuclear envelope, endoplasmic reticulum, Golgi apparatus, or plasma membrane) via specialized transport systems like vesicles and transport channels.

Intercellular protein transport refers to the movement of proteins from one cell to another, often facilitated by exocytosis (release of proteins in vesicles) and endocytosis (uptake of extracellular substances via membrane-bound vesicles). This is essential for communication between cells, immune response, and other physiological processes.

It's important to note that any disruption in protein transport can lead to various diseases, including neurological disorders, cancer, and metabolic conditions.

Phosphatidylcholines (PtdCho) are a type of phospholipids that are essential components of cell membranes in living organisms. They are composed of a hydrophilic head group, which contains a choline moiety, and two hydrophobic fatty acid chains. Phosphatidylcholines are crucial for maintaining the structural integrity and function of cell membranes, and they also serve as important precursors for the synthesis of signaling molecules such as acetylcholine. They can be found in various tissues and biological fluids, including blood, and are abundant in foods such as soybeans, eggs, and meat. Phosphatidylcholines have been studied for their potential health benefits, including their role in maintaining healthy lipid metabolism and reducing the risk of cardiovascular disease.

Biological models, also known as physiological models or organismal models, are simplified representations of biological systems, processes, or mechanisms that are used to understand and explain the underlying principles and relationships. These models can be theoretical (conceptual or mathematical) or physical (such as anatomical models, cell cultures, or animal models). They are widely used in biomedical research to study various phenomena, including disease pathophysiology, drug action, and therapeutic interventions.

Examples of biological models include:

1. Mathematical models: These use mathematical equations and formulas to describe complex biological systems or processes, such as population dynamics, metabolic pathways, or gene regulation networks. They can help predict the behavior of these systems under different conditions and test hypotheses about their underlying mechanisms.
2. Cell cultures: These are collections of cells grown in a controlled environment, typically in a laboratory dish or flask. They can be used to study cellular processes, such as signal transduction, gene expression, or metabolism, and to test the effects of drugs or other treatments on these processes.
3. Animal models: These are living organisms, usually vertebrates like mice, rats, or non-human primates, that are used to study various aspects of human biology and disease. They can provide valuable insights into the pathophysiology of diseases, the mechanisms of drug action, and the safety and efficacy of new therapies.
4. Anatomical models: These are physical representations of biological structures or systems, such as plastic models of organs or tissues, that can be used for educational purposes or to plan surgical procedures. They can also serve as a basis for developing more sophisticated models, such as computer simulations or 3D-printed replicas.

Overall, biological models play a crucial role in advancing our understanding of biology and medicine, helping to identify new targets for therapeutic intervention, develop novel drugs and treatments, and improve human health.

A cell line is a culture of cells that are grown in a laboratory for use in research. These cells are usually taken from a single cell or group of cells, and they are able to divide and grow continuously in the lab. Cell lines can come from many different sources, including animals, plants, and humans. They are often used in scientific research to study cellular processes, disease mechanisms, and to test new drugs or treatments. Some common types of human cell lines include HeLa cells (which come from a cancer patient named Henrietta Lacks), HEK293 cells (which come from embryonic kidney cells), and HUVEC cells (which come from umbilical vein endothelial cells). It is important to note that cell lines are not the same as primary cells, which are cells that are taken directly from a living organism and have not been grown in the lab.

Diphenylhexatriene (DPH) is a fluorescent chemical compound that is often used in research and scientific studies as a probe to investigate the properties and behavior of lipid membranes in cells. It is particularly useful for studying the mobility and orientation of lipids within membranes, as well as the fluidity and microviscosity of the membrane environment.

When DPH is incorporated into a lipid membrane, it can emit fluorescence when excited with light at a specific wavelength. The intensity and polarization of the emitted fluorescence can provide information about the motion and orientation of the DPH molecules, which in turn can reveal details about the physical properties of the membrane.

It's worth noting that while DPH is a valuable tool for studying lipid membranes, it is not typically used as a medical diagnostic or therapeutic agent.

Membrane proteins are a type of protein that are embedded in the lipid bilayer of biological membranes, such as the plasma membrane of cells or the inner membrane of mitochondria. These proteins play crucial roles in various cellular processes, including:

1. Cell-cell recognition and signaling
2. Transport of molecules across the membrane (selective permeability)
3. Enzymatic reactions at the membrane surface
4. Energy transduction and conversion
5. Mechanosensation and signal transduction

Membrane proteins can be classified into two main categories: integral membrane proteins, which are permanently associated with the lipid bilayer, and peripheral membrane proteins, which are temporarily or loosely attached to the membrane surface. Integral membrane proteins can further be divided into three subcategories based on their topology:

1. Transmembrane proteins, which span the entire width of the lipid bilayer with one or more alpha-helices or beta-barrels.
2. Lipid-anchored proteins, which are covalently attached to lipids in the membrane via a glycosylphosphatidylinositol (GPI) anchor or other lipid modifications.
3. Monotopic proteins, which are partially embedded in the membrane and have one or more domains exposed to either side of the bilayer.

Membrane proteins are essential for maintaining cellular homeostasis and are targets for various therapeutic interventions, including drug development and gene therapy. However, their structural complexity and hydrophobicity make them challenging to study using traditional biochemical methods, requiring specialized techniques such as X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and single-particle cryo-electron microscopy (cryo-EM).

Phospholipids are a major class of lipids that consist of a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) tails. The head is composed of a phosphate group, which is often bound to an organic molecule such as choline, ethanolamine, serine or inositol. The tails are made up of two fatty acid chains.

Phospholipids are a key component of cell membranes and play a crucial role in maintaining the structural integrity and function of the cell. They form a lipid bilayer, with the hydrophilic heads facing outwards and the hydrophobic tails facing inwards, creating a barrier that separates the interior of the cell from the outside environment.

Phospholipids are also involved in various cellular processes such as signal transduction, intracellular trafficking, and protein function regulation. Additionally, they serve as emulsifiers in the digestive system, helping to break down fats in the diet.

Freeze etching is not a medical term per se, but it is a technique used in scientific research and analysis, including some medical fields such as microbiology and cell biology. Here's a brief explanation:

Freeze etching (also known as freeze-fracture replication) is a preparation technique for electron microscopy that allows the observation of biological specimens at high resolution. This method involves rapid freezing of a sample to preserve its natural structure, followed by fracturing it at low temperatures to expose internal surfaces. The exposed surface is then etched, or lightly bombarded with ions to remove thin layers of ice and reveal more detail. A layer of metal (usually platinum or gold) is then evaporated onto the surface at an oblique angle, creating a replica of the surface structure. This replica can be examined in a transmission electron microscope (TEM).

This technique is particularly useful for studying cell membranes and their associated structures, as it allows researchers to observe the distribution and organization of proteins and lipids within these membranes at high resolution.

Erythrocytes, also known as red blood cells (RBCs), are the most common type of blood cell in circulating blood in mammals. They are responsible for transporting oxygen from the lungs to the body's tissues and carbon dioxide from the tissues to the lungs.

Erythrocytes are formed in the bone marrow and have a biconcave shape, which allows them to fold and bend easily as they pass through narrow blood vessels. They do not have a nucleus or mitochondria, which makes them more flexible but also limits their ability to reproduce or repair themselves.

In humans, erythrocytes are typically disc-shaped and measure about 7 micrometers in diameter. They contain the protein hemoglobin, which binds to oxygen and gives blood its red color. The lifespan of an erythrocyte is approximately 120 days, after which it is broken down in the liver and spleen.

Abnormalities in erythrocyte count or function can lead to various medical conditions, such as anemia, polycythemia, and sickle cell disease.

Fluorescence microscopy is a type of microscopy that uses fluorescent dyes or proteins to highlight and visualize specific components within a sample. In this technique, the sample is illuminated with high-energy light, typically ultraviolet (UV) or blue light, which excites the fluorescent molecules causing them to emit lower-energy, longer-wavelength light, usually visible light in the form of various colors. This emitted light is then collected by the microscope and detected to produce an image.

Fluorescence microscopy has several advantages over traditional brightfield microscopy, including the ability to visualize specific structures or molecules within a complex sample, increased sensitivity, and the potential for quantitative analysis. It is widely used in various fields of biology and medicine, such as cell biology, neuroscience, and pathology, to study the structure, function, and interactions of cells and proteins.

There are several types of fluorescence microscopy techniques, including widefield fluorescence microscopy, confocal microscopy, two-photon microscopy, and total internal reflection fluorescence (TIRF) microscopy, each with its own strengths and limitations. These techniques can provide valuable insights into the behavior of cells and proteins in health and disease.

Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.

In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.

Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.

Membrane transport proteins are specialized biological molecules, specifically integral membrane proteins, that facilitate the movement of various substances across the lipid bilayer of cell membranes. They are responsible for the selective and regulated transport of ions, sugars, amino acids, nucleotides, and other molecules into and out of cells, as well as within different cellular compartments. These proteins can be categorized into two main types: channels and carriers (or pumps). Channels provide a passive transport mechanism, allowing ions or small molecules to move down their electrochemical gradient, while carriers actively transport substances against their concentration gradient, requiring energy usually in the form of ATP. Membrane transport proteins play a crucial role in maintaining cell homeostasis, signaling processes, and many other physiological functions.

Membrane glycoproteins are proteins that contain oligosaccharide chains (glycans) covalently attached to their polypeptide backbone. They are integral components of biological membranes, spanning the lipid bilayer and playing crucial roles in various cellular processes.

The glycosylation of these proteins occurs in the endoplasmic reticulum (ER) and Golgi apparatus during protein folding and trafficking. The attached glycans can vary in structure, length, and composition, which contributes to the diversity of membrane glycoproteins.

Membrane glycoproteins can be classified into two main types based on their orientation within the lipid bilayer:

1. Type I (N-linked): These glycoproteins have a single transmembrane domain and an extracellular N-terminus, where the oligosaccharides are predominantly attached via asparagine residues (Asn-X-Ser/Thr sequon).
2. Type II (C-linked): These glycoproteins possess two transmembrane domains and an intracellular C-terminus, with the oligosaccharides linked to tryptophan residues via a mannose moiety.

Membrane glycoproteins are involved in various cellular functions, such as:

* Cell adhesion and recognition
* Receptor-mediated signal transduction
* Enzymatic catalysis
* Transport of molecules across membranes
* Cell-cell communication
* Immunological responses

Some examples of membrane glycoproteins include cell surface receptors (e.g., growth factor receptors, cytokine receptors), adhesion molecules (e.g., integrins, cadherins), and transporters (e.g., ion channels, ABC transporters).

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Detergents are cleaning agents that are often used to remove dirt, grease, and stains from various surfaces. They contain one or more surfactants, which are compounds that lower the surface tension between two substances, such as water and oil, allowing them to mix more easily. This makes it possible for detergents to lift and suspend dirt particles in water so they can be rinsed away.

Detergents may also contain other ingredients, such as builders, which help to enhance the cleaning power of the surfactants by softening hard water or removing mineral deposits. Some detergents may also include fragrances, colorants, and other additives to improve their appearance or performance.

In a medical context, detergents are sometimes used as disinfectants or antiseptics, as they can help to kill bacteria, viruses, and other microorganisms on surfaces. However, it is important to note that not all detergents are effective against all types of microorganisms, and some may even be toxic or harmful if used improperly.

It is always important to follow the manufacturer's instructions when using any cleaning product, including detergents, to ensure that they are used safely and effectively.

Temperature, in a medical context, is a measure of the degree of hotness or coldness of a body or environment. It is usually measured using a thermometer and reported in degrees Celsius (°C), degrees Fahrenheit (°F), or kelvin (K). In the human body, normal core temperature ranges from about 36.5-37.5°C (97.7-99.5°F) when measured rectally, and can vary slightly depending on factors such as time of day, physical activity, and menstrual cycle. Elevated body temperature is a common sign of infection or inflammation, while abnormally low body temperature can indicate hypothermia or other medical conditions.

Cell fractionation is a laboratory technique used to separate different cellular components or organelles based on their size, density, and other physical properties. This process involves breaking open the cell (usually through homogenization), and then separating the various components using various methods such as centrifugation, filtration, and ultracentrifugation.

The resulting fractions can include the cytoplasm, mitochondria, nuclei, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, and other organelles. Each fraction can then be analyzed separately to study the biochemical and functional properties of the individual components.

Cell fractionation is a valuable tool in cell biology research, allowing scientists to study the structure, function, and interactions of various cellular components in a more detailed and precise manner.

Calcium is an essential mineral that is vital for various physiological processes in the human body. The medical definition of calcium is as follows:

Calcium (Ca2+) is a crucial cation and the most abundant mineral in the human body, with approximately 99% of it found in bones and teeth. It plays a vital role in maintaining structural integrity, nerve impulse transmission, muscle contraction, hormonal secretion, blood coagulation, and enzyme activation.

Calcium homeostasis is tightly regulated through the interplay of several hormones, including parathyroid hormone (PTH), calcitonin, and vitamin D. Dietary calcium intake, absorption, and excretion are also critical factors in maintaining optimal calcium levels in the body.

Hypocalcemia refers to low serum calcium levels, while hypercalcemia indicates high serum calcium levels. Both conditions can have detrimental effects on various organ systems and require medical intervention to correct.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

The endoplasmic reticulum (ER) is a network of interconnected tubules and sacs that are present in the cytoplasm of eukaryotic cells. It is a continuous membranous organelle that plays a crucial role in the synthesis, folding, modification, and transport of proteins and lipids.

The ER has two main types: rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER). RER is covered with ribosomes, which give it a rough appearance, and is responsible for protein synthesis. On the other hand, SER lacks ribosomes and is involved in lipid synthesis, drug detoxification, calcium homeostasis, and steroid hormone production.

In summary, the endoplasmic reticulum is a vital organelle that functions in various cellular processes, including protein and lipid metabolism, calcium regulation, and detoxification.

"Cells, cultured" is a medical term that refers to cells that have been removed from an organism and grown in controlled laboratory conditions outside of the body. This process is called cell culture and it allows scientists to study cells in a more controlled and accessible environment than they would have inside the body. Cultured cells can be derived from a variety of sources, including tissues, organs, or fluids from humans, animals, or cell lines that have been previously established in the laboratory.

Cell culture involves several steps, including isolation of the cells from the tissue, purification and characterization of the cells, and maintenance of the cells in appropriate growth conditions. The cells are typically grown in specialized media that contain nutrients, growth factors, and other components necessary for their survival and proliferation. Cultured cells can be used for a variety of purposes, including basic research, drug development and testing, and production of biological products such as vaccines and gene therapies.

It is important to note that cultured cells may behave differently than they do in the body, and results obtained from cell culture studies may not always translate directly to human physiology or disease. Therefore, it is essential to validate findings from cell culture experiments using additional models and ultimately in clinical trials involving human subjects.

Carrier proteins, also known as transport proteins, are a type of protein that facilitates the movement of molecules across cell membranes. They are responsible for the selective and active transport of ions, sugars, amino acids, and other molecules from one side of the membrane to the other, against their concentration gradient. This process requires energy, usually in the form of ATP (adenosine triphosphate).

Carrier proteins have a specific binding site for the molecule they transport, and undergo conformational changes upon binding, which allows them to move the molecule across the membrane. Once the molecule has been transported, the carrier protein returns to its original conformation, ready to bind and transport another molecule.

Carrier proteins play a crucial role in maintaining the balance of ions and other molecules inside and outside of cells, and are essential for many physiological processes, including nerve impulse transmission, muscle contraction, and nutrient uptake.

Tertiary protein structure refers to the three-dimensional arrangement of all the elements (polypeptide chains) of a single protein molecule. It is the highest level of structural organization and results from interactions between various side chains (R groups) of the amino acids that make up the protein. These interactions, which include hydrogen bonds, ionic bonds, van der Waals forces, and disulfide bridges, give the protein its unique shape and stability, which in turn determines its function. The tertiary structure of a protein can be stabilized by various factors such as temperature, pH, and the presence of certain ions. Any changes in these factors can lead to denaturation, where the protein loses its tertiary structure and thus its function.

Scanning electron microscopy (SEM) is a type of electron microscopy that uses a focused beam of electrons to scan the surface of a sample and produce a high-resolution image. In SEM, a beam of electrons is scanned across the surface of a specimen, and secondary electrons are emitted from the sample due to interactions between the electrons and the atoms in the sample. These secondary electrons are then detected by a detector and used to create an image of the sample's surface topography. SEM can provide detailed images of the surface of a wide range of materials, including metals, polymers, ceramics, and biological samples. It is commonly used in materials science, biology, and electronics for the examination and analysis of surfaces at the micro- and nanoscale.

The Golgi apparatus, also known as the Golgi complex or simply the Golgi, is a membrane-bound organelle found in the cytoplasm of most eukaryotic cells. It plays a crucial role in the processing, sorting, and packaging of proteins and lipids for transport to their final destinations within the cell or for secretion outside the cell.

The Golgi apparatus consists of a series of flattened, disc-shaped sacs called cisternae, which are stacked together in a parallel arrangement. These stacks are often interconnected by tubular structures called tubules or vesicles. The Golgi apparatus has two main faces: the cis face, which is closest to the endoplasmic reticulum (ER) and receives proteins and lipids directly from the ER; and the trans face, which is responsible for sorting and dispatching these molecules to their final destinations.

The Golgi apparatus performs several essential functions in the cell:

1. Protein processing: After proteins are synthesized in the ER, they are transported to the cis face of the Golgi apparatus, where they undergo various post-translational modifications, such as glycosylation (the addition of sugar molecules) and sulfation. These modifications help determine the protein's final structure, function, and targeting.
2. Lipid modification: The Golgi apparatus also modifies lipids by adding or removing different functional groups, which can influence their properties and localization within the cell.
3. Protein sorting and packaging: Once proteins and lipids have been processed, they are sorted and packaged into vesicles at the trans face of the Golgi apparatus. These vesicles then transport their cargo to various destinations, such as lysosomes, plasma membrane, or extracellular space.
4. Intracellular transport: The Golgi apparatus serves as a central hub for intracellular trafficking, coordinating the movement of vesicles and other transport carriers between different organelles and cellular compartments.
5. Cell-cell communication: Some proteins that are processed and packaged in the Golgi apparatus are destined for secretion, playing crucial roles in cell-cell communication and maintaining tissue homeostasis.

In summary, the Golgi apparatus is a vital organelle involved in various cellular processes, including post-translational modification, sorting, packaging, and intracellular transport of proteins and lipids. Its proper functioning is essential for maintaining cellular homeostasis and overall organismal health.

Cholesterol is a type of lipid (fat) molecule that is an essential component of cell membranes and is also used to make certain hormones and vitamins in the body. It is produced by the liver and is also obtained from animal-derived foods such as meat, dairy products, and eggs.

Cholesterol does not mix with blood, so it is transported through the bloodstream by lipoproteins, which are particles made up of both lipids and proteins. There are two main types of lipoproteins that carry cholesterol: low-density lipoproteins (LDL), also known as "bad" cholesterol, and high-density lipoproteins (HDL), also known as "good" cholesterol.

High levels of LDL cholesterol in the blood can lead to a buildup of cholesterol in the walls of the arteries, increasing the risk of heart disease and stroke. On the other hand, high levels of HDL cholesterol are associated with a lower risk of these conditions because HDL helps remove LDL cholesterol from the bloodstream and transport it back to the liver for disposal.

It is important to maintain healthy levels of cholesterol through a balanced diet, regular exercise, and sometimes medication if necessary. Regular screening is also recommended to monitor cholesterol levels and prevent health complications.

Unilamellar liposomes are a type of liposome that consists of a single phospholipid bilayer membrane enclosing an aqueous compartment. They are spherical vesicles, ranging in size from 20 nanometers to several micrometers, and can be used as drug delivery systems for various therapeutic agents, including hydrophilic drugs (in the aqueous compartment) and hydrophobic drugs (incorporated into the lipid bilayer). The single membrane structure of unilamellar liposomes distinguishes them from multilamellar liposomes, which have multiple concentric phospholipid bilayers.

Fluorescence Polarization (FP) is not a medical term per se, but a technique used in medical research and diagnostics. Here's a general definition:

Fluorescence Polarization is a biophysical technique used to measure the rotational movement of molecules in solution after they have been excited by polarized light. When a fluorophore (a fluorescent molecule) absorbs light, its electrons become excited and then return to their ground state, releasing energy in the form of light. This emitted light often has different properties than the incident light, one of which can be its polarization. If the fluorophore is large or bound to a large structure, it may not rotate significantly during the time between absorption and emission, resulting in emitted light that maintains the same polarization as the excitation light. Conversely, if the fluorophore is small or unbound, it will rotate rapidly during this period, and the emitted light will be depolarized. By measuring the degree of polarization of the emitted light, researchers can gain information about the size, shape, and mobility of the fluorophore and the molecules to which it is attached. This technique is widely used in various fields including life sciences, biochemistry, and diagnostics.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

'Cellular structures' is a broad term that refers to the various components and organizations of cells in living organisms. In a medical context, it can refer to the study of cellular morphology and organization in various tissues and organs, as well as changes in these structures that may be associated with disease or injury.

Cellular structures can include:

1. Cell membrane: The outer boundary of the cell that separates it from the extracellular environment and regulates the movement of molecules into and out of the cell.
2. Cytoplasm: The contents of the cell, including organelles such as mitochondria, ribosomes, endoplasmic reticulum, and Golgi apparatus.
3. Nucleus: The central organelle that contains the genetic material (DNA) of the cell and controls its activities.
4. Mitochondria: Organelles that generate energy for the cell through a process called cellular respiration.
5. Endoplasmic reticulum (ER): A network of tubules and sacs that serve as a site for protein synthesis, folding, and modification.
6. Golgi apparatus: A membrane-bound organelle that modifies, sorts, and packages proteins and lipids for transport to other parts of the cell or for secretion from the cell.
7. Lysosomes: Organelles that contain enzymes that break down waste materials and cellular debris.
8. Cytoskeleton: A network of protein filaments that provide structure, shape, and movement to the cell.
9. Ribosomes: Organelles that synthesize proteins using instructions from the DNA in the nucleus.

Abnormalities in these cellular structures can be associated with various medical conditions, such as cancer, genetic disorders, infectious diseases, and neurodegenerative disorders.

Fluorescent dyes are substances that emit light upon excitation by absorbing light of a shorter wavelength. In a medical context, these dyes are often used in various diagnostic tests and procedures to highlight or mark certain structures or substances within the body. For example, fluorescent dyes may be used in imaging techniques such as fluorescence microscopy or fluorescence angiography to help visualize cells, tissues, or blood vessels. These dyes can also be used in flow cytometry to identify and sort specific types of cells. The choice of fluorescent dye depends on the specific application and the desired properties, such as excitation and emission spectra, quantum yield, and photostability.

Confocal microscopy is a powerful imaging technique used in medical and biological research to obtain high-resolution, contrast-rich images of thick samples. This super-resolution technology provides detailed visualization of cellular structures and processes at various depths within a specimen.

In confocal microscopy, a laser beam focused through a pinhole illuminates a small spot within the sample. The emitted fluorescence or reflected light from this spot is then collected by a detector, passing through a second pinhole that ensures only light from the focal plane reaches the detector. This process eliminates out-of-focus light, resulting in sharp images with improved contrast compared to conventional widefield microscopy.

By scanning the laser beam across the sample in a raster pattern and collecting fluorescence at each point, confocal microscopy generates optical sections of the specimen. These sections can be combined to create three-dimensional reconstructions, allowing researchers to study cellular architecture and interactions within complex tissues.

Confocal microscopy has numerous applications in medical research, including studying protein localization, tracking intracellular dynamics, analyzing cell morphology, and investigating disease mechanisms at the cellular level. Additionally, it is widely used in clinical settings for diagnostic purposes, such as analyzing skin lesions or detecting pathogens in patient samples.

"Membrane Structure." The Journal of Cell Biology. (1981) 91. 189s-204s. B Alberts, A Johnson, J Lewis, M Raff, K Roberts, and P ... P Mueller, D O Rudin, H I Tien, and W C Wescott."Reconstitution of cell membrane structure in vitro and its transformation into ... S J Singer and G L Nicolson."The fluid mosaic model of the structure of cell membranes." Science. (1972) 175. 720-731. A B ... "Membrane structure." The Journal of Cell Biology. (1981) 91. 189s-204s. (CS1: Julian-Gregorian uncertainty, History of biology ...
Annular lipid shell Artificial cell Bacterial cell structure Bangstad syndrome Cell cortex Cell damage, including damage to ... cell membrane Cell theory Cytoneme Elasticity of cell membranes Gram-positive bacteria Membrane models Membrane nanotubule ... plasmatic membrane (Pfeffer, 1900), plasma membrane, cytoplasmic membrane, cell envelope and cell membrane. Some authors who ... The basolateral membrane or basolateral cell membrane of a polarized cell is the surface of the plasma membrane that forms its ...
... and cell membranes" (PDF). Annual Review of Biophysics and Biomolecular Structure. 33: 269-95. doi:10.1146/annurev.biophys. ... In biology, membrane fluidity refers to the viscosity of the lipid bilayer of a cell membrane or a synthetic lipid membrane. ... Membrane fluidity is also affected by cholesterol. Cholesterol can make the cell membrane fluid as well as rigid. Membrane ... Membrane fluidity is known to affect the function of biomolecules residing within or associated with the membrane structure. ...
The fences and pickets model of plasma membrane is a concept of cell membrane structure suggesting that the fluid plasma ... Kusumi A, Sako Y (August 1996). "Cell surface organization by the membrane skeleton". Current Opinion in Cell Biology. 8 (4): ... This model differs from older cell membrane structure concepts such as the Singer-Nicolson fluid mosaic model and the Saffman- ... "Three-dimensional reconstruction of the membrane skeleton at the plasma membrane interface by electron tomography". J. Cell ...
... which is embedded in the cell membrane. The TMD and ATS are highly conserved among different PfEMP1s, and their structures have ... from the intraerythrocytic asexual parasite to the cytoplasmic face of the host cell membrane". The Journal of Cell Biology. ... It was discovered in 1984 when it was reported that infected RBCs had unusually large-sized cell membrane proteins, and these ... Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a family of proteins present on the membrane surface of red ...
The authors attribute this dramatic performance increase to modifications to the electronic structure of the surface, reducing ... Proton-exchange membrane fuel cells (PEMFC), also known as polymer electrolyte membrane (PEM) fuel cells, are a type of fuel ... Before the invention of PEM fuel cells, existing fuel cell types such as solid-oxide fuel cells were only applied in extreme ... the fuel cell. The membrane must also not allow either gas to pass to the other side of the cell, a problem known as gas ...
Cell membranes require high levels of cholesterol - typically an average of 20% cholesterol in the whole membrane, increasing ... membranes?ev=prf_pub de Meyer F, Smit B. Effect of cholesterol on the structure of a phospholipid bilayer. Proc Natl Acad Sci U ... The bilayer formed by membrane lipids serves as a containment unit of a living cell. Membrane lipids also form a matrix in ... which form the lipid bilayer of the cell membrane. The three major classes of membrane lipids are phospholipids, glycolipids, ...
Murphy, C.R. The plasma membrane of uterine epithelial cells: structure and histochemistry. Gustav Fischer Verlag: Stuttgart ... Plasma membrane transformation: a common response of uterine epithelial cells during the peri-implantation period. Cell Biology ... Murphy, CR (August 2004). "Uterine receptivity and the plasma membrane transformation". Cell Research. 14 (4): 259-67. doi: ... Junctional barrier complexes undergo major alterations during the plasma membrane transformation of uterine epithelial cells. ...
"Structure of a Membrane". The Lipid Chronicles. 5 November 2011. Retrieved 2020-06-02. Schubert, D; Behl, C; Lesley, R; Brack, ... "3.1 The cell membrane". Anatomy & physiology. OpenStax. ISBN 978-1-947172-04-3. Retrieved 14 May 2023. "Amphipathic". Biology- ... The phospholipid amphiphiles are the major structural component of cell membranes. Amphiphiles are the basis for a number of ... strongly interact with biological membranes by insertion of the hydrophobic part into the lipid membrane, while exposing the ...
Microtubular associated membranes are found in various cell types and are essential for maintaining cell structure and function ... A microtubular membrane is a type of membrane made up of small tubular structures. ... and stability to the cell, as well as act as tracks for transporting materials within the cell. Overall, microtubular membranes ... A characteristic feature of protozoan parasites is an ordered layer of microtubules beneath the cell membrane.: 152 The ...
In order to move, these cells will often modify their structure via lamellipodia and filopodia. The membrane must be able to ... An example of naturally occurring membrane is the lipid bilayer of cells, also known as cellular membranes. Synthetic membranes ... The cell membrane must be able to curve around and fit the shape determined by these functions. This requires the membrane to ... McMahon HT, Gallop JL (December 2005). "Membrane curvature and mechanisms of dynamic cell membrane remodelling". Nature. 438 ( ...
... s (mPRs) are a group of cell surface receptors and membrane steroid receptors belonging to the ... therefore they are found in the plasmatic membrane. Studies have not revealed significant information about its structure so ... membrane progesterone receptors are good candidates for the membrane receptors mediating many of the nonclassical cell surface- ... Immunohistochemical studies revealed that mPRγ is associated with the apical membrane of ciliated cells in the lumen of the ...
Singer, S. Jonathan; Nicolson, Garth L. (1972), "The fluid mosaic model of the structure of cell membranes", Science, 175 (23 ... A cell membrane defines a boundary between a cell and its environment. The primary constituent of a membrane is a phospholipid ... A cell membrane is simplified as lipid bilayer plus membrane skeleton. The skeleton is a cross-linking protein network and ... Physics of Composite Cell Membrane and Actin Based Cytoskeleton, in Physics of bio-molecules and cells, Edited by H. Flyvbjerg ...
Risinger, Mary; Kalfa, Theodosia A. (2020). "Red cell membrane disorders: Structure meets function". Blood. 136 (11): 1250-1261 ... The erythrocytes' cell membranes may abnormally 'leak' sodium and/or potassium ions, causing abnormalities in cell volume. ... The resulting abnormal sterol composition of erythrocyte cell membranes causes them to appear as deformed stomatocytes on ... including sickle cell disease and malaria resistance. Osmosis leads to the red blood cell having a constant tendency to swell ...
All cells have a plasma membrane. In a protist, the plasma membrane is also known as the plasmalemma. Just below the plasma ... The pellicle structure in the protist is a thin layer of protein that helps provide the cell with some support and protection. ... The members of the phylum Euglenozoa have a pellicle for support, a red eye spot called a stigma to orient the cell toward ... These cysts on reaching the terminal ileum region of the gastrointestinal tract give rise to a mass of proliferating cells, the ...
Luis Nieva J, Carrasco L (October 2015). "Viroporins: Structures and Functions beyond Cell Membrane Permeabilization". Viruses ... the membrane permeability changes may be sufficient to induce cell lysis, thereby permitting the new virions to exit the cell. ... The most well-studied and well-established function of viroporins is the permeabilization of the cell membrane to ions and ... Viroporins are capable of assembling into oligomeric ion channels or pores in the host cell's membrane, rendering it more ...
"The Red Cell Membrane: structure and pathologies" (PDF). Australian Centre for Blood Diseases/Monash University. Retrieved 24 ... Hematopoietic stem cells in the bone marrow can give rise to hematopoietic lineage cells, and mesenchymal stem cells, which can ... inhibiting immature blood cells from leaving the marrow. Only mature blood cells contain the membrane proteins, such as ... which are also known as marrow stromal cells. These are multipotent stem cells that can differentiate into a variety of cell ...
... and nanoporous membranes. Gyroid membrane structures are occasionally found inside cells. Gyroid structures have photonic band ... The gyroid mitochondrial membranes found in the retinal cone cells of certain tree shrew species present a unique structure ... Such self-assembled polymer structures have found applications in experimental supercapacitors, solar cells photocatalysts, ... These interwoven structures are one of the smallest free-standing graphene 3D structures. They are conductive, mechanically ...
Nieva, José; Carrasco, Luis (29 September 2015). "Viroporins: Structures and functions beyond cell membrane permeabilization". ... Holins form pores in the host's cell membrane, allowing lysins to reach and degrade peptidoglycan, a component of bacterial ... Viruses that infect eukaryotic cells may use similar channel-forming proteins called viroporins. According to their structure ... They are associated with SAR endolysins, which remain inactive in the periplasm prior to the depolarization of the membrane. ...
Weinstein, Ronald S. (1969-07-10). "The Structure of Cell Membranes". New England Journal of Medicine. 281 (2): 86-89. doi: ... He continued his research on normal cell membranes and cancer cell membranes and initiated research on animal models for ... As an MGH pathology resident, he co-authored research papers on intercellular junctions, cancer cell, and red cell membranes. ... He studied cell membrane properties in normal epithelium, pre-cancers and cancers. Medical science education reform To ...
Robertson, J.D. (1959). "The ultra structure of cell membranes and their derivatives, Biochem". Soc. Syrup: 3. Suganuma A (1966 ... The appearance of these mesosome-like structures may be the result of these chemicals damaging the plasma membrane and/or cell ... These structures are invaginations of the plasma membrane observed in gram-positive bacteria that have been chemically fixed to ... Cell membrane Organelle Lysosome Nanninga N (1971). "The mesosome of Bacillus subtilis as affected by chemical and physical ...
The purpose of a membrane is to prohibit the penetration of cells, primarily epithelial, through its structure. The bone tissue ... In absence of a barrier membrane, the defect would be occupied by soft tissue cells. When barrier membranes are utilized, the ... Hence, if a bone defect needs to heal, the membrane separates it from the soft tissue, giving time for the bone cells to fill ... Collagen absorbable barrier membranes do not require surgical removal, inhibit migration of epithelial cells, promote the ...
Cho, W. & Stahelin, R.V. (June 2005). "Membrane-protein interactions in cell signaling and membrane trafficking". Annual Review ... They share a common and characteristic tertiary structure that consists of a beta barrel packed around an alpha helix in the ... Tubby domains associate with cytoplasmic side of cell membranes through binding of different phosphoinositides TUB; TULP1; ... Tubby proteins can bind the small cell signaling molecule phosphatidylinositol, which is typically localized to the cell ...
... is found in a membrane within the cell. It is likely tmem242 is found in the cellular membrane or the mitochondrial ... The tmem242 protein further folds to its final structure to embed in a membrane. It is likely tmem242 is embedded in the ... These structures use binding, both traditional and modified, to create stem loop structures in the untranslated regions of the ... there is also potential for tmem242 to embed in the mitochondrial membrane or the endoplasmic reticulum membrane. Tmem242 ...
... showing the connection between thrombocytes and immune cells. The platelet cell membrane has receptors for collagen. Following ... Circulating inactivated platelets are biconvex discoid (lens-shaped) structures,: 117-118 2-3 µm in greatest diameter. ... Berridge, Michael J. (1 October 2014). "Module 11: Cell Stress, Inflammatory Responses and Cell Death" (PDF). Cell Signalling ... "Programmed anuclear cell death delimits platelet life span". Cell. 128 (6): 1173-1186. doi:10.1016/j.cell.2007.01.037. PMID ...
The structure of biological membranes (2nd ed.). United States: CRC Press. Yeagle, P. (1993). The membranes of cells (2nd ed ... and hexagonal aqueous-lipid structures, in aqueous dispersions of membrane lipids. As water-soluble negative stain is excluded ... Polymorphism in biophysics is the ability of lipids to aggregate in a variety of ways, giving rise to structures of different ... This phase is only seen under unique, specialized conditions, and most likely is not relevant for biological membranes. Lipid ...
Whyte JR, Munro S (June 2002). "Vesicle tethering complexes in membrane traffic". J Cell Sci. 115 (Pt 13): 2627-37. doi:10.1242 ... Short B, Haas A, Barr FA (June 2005). "Golgins and GTPases, giving identity and structure to the Golgi apparatus". Biochim ... dephosphorylated protein associates with the Golgi membrane and dissociates from the membrane upon phosphorylation. Ras- ... Nelson DS, Alvarez C, Gao YS, García-Mata R, Fialkowski E, Sztul E (1998). "The membrane transport factor TAP/p115 cycles ...
LTA is anchored to the cell membrane via a diacylglycerol. It acts as regulator of autolytic wall enzymes (muramidases). It has ... The structure of LTA varies between the different species of Gram-positive bacteria and may contain long chains of ribitol or ... LTA may bind to target cells non-specifically through membrane phospholipids, or specifically to CD14 and to Toll-like ... "Lipoteichoic Acid from Lacticaseibacillus rhamnosus GG Modulates Dendritic Cells and T Cells in the Gut". Nutrients. 14 (3): ...
Membrane Surrounding Lipid Vacuoles in L 1210 lymphoid Leukemic Cells. Cell structure and Function 5, 211-215, 1980. Dai Duy ... Starting from here, he went deeply into the research field of cancer cell membrane. During four years working hard in the ... He has published dozens of articles for research on cancer cell membranes in English on the scientific subjected journals of ... TB 88,401 MEDLINE Search Results Cell Structure and Function Replacement of calcium by cadmium ions Dr. Dai Duy Ban - Daibio ...
It is phenylalanine rich, and found in the cell membrane. Phyre2 extrapolated the following 3D secondary structure with 100% ... STRUCTURE) PTCHD4 has been implicated as an integral component of cellular membrane, and as a protein receptor in the hedgehog ... It also appears to be important to adult animals, as it has been implicated in the regulation of adult stem cells, while its ... The later of these two functions causes an inhibitory effect during the development of embryonic cells in all bilaterians and ...
Structures which are part of the CELL MEMBRANE or have cell membrane as a major part of their structure. ... "Cell Membrane Structures" by people in Harvard Catalyst Profiles by year, and whether "Cell Membrane Structures" was a major or ... Bleb Expansion in Migrating Cells Depends on Supply of Membrane from Cell Surface Invaginations. Dev Cell. 2017 12 04; 43(5): ... "Cell Membrane Structures" is a descriptor in the National Library of Medicines controlled vocabulary thesaurus, MeSH (Medical ...
Life sciences/Cell biology/Cellular physiology/Cell morphology/Cell structure/Cell membranes. ...
REGULAR STRUCTURES IN MEMBRANES : I. Membranes in the Endocytic Complex of Ileal Epithelial Cells . J Cell Biol 1 September ... REGULAR STRUCTURES IN MEMBRANES : I. Membranes in the Endocytic Complex of Ileal Epithelial Cells S. Knutton, S. Knutton ... MEMBRANE MODIFICATIONS IN THE APICAL ENDOCYTIC COMPLEX OF ILEAL EPITHELIAL CELLS Regular structures in unit membranes. II. ... Regular structures in unit membranes. III. Further observations on the particulate component of the suckling rat ileum ...
"Membrane Structure." The Journal of Cell Biology. (1981) 91. 189s-204s. B Alberts, A Johnson, J Lewis, M Raff, K Roberts, and P ... P Mueller, D O Rudin, H I Tien, and W C Wescott."Reconstitution of cell membrane structure in vitro and its transformation into ... S J Singer and G L Nicolson."The fluid mosaic model of the structure of cell membranes." Science. (1972) 175. 720-731. A B ... "Membrane structure." The Journal of Cell Biology. (1981) 91. 189s-204s. (CS1: Julian-Gregorian uncertainty, History of biology ...
Cell Membrane / chemistry * Cell Membrane / virology* * Crystallography, X-Ray * DEAD Box Protein 58 ... Flavivirus NS1 structures reveal surfaces for associations with membranes and the immune system Science. 2014 Feb 21;343(6173): ... The NS1 structures reveal distinct domains for membrane association of the dimer and interactions with the immune system and ... We report crystal structures for full-length, glycosylated NS1 from West Nile and dengue viruses. The NS1 hexamer in crystal ...
Image Result For Cell Membrane Worksheet Cell Membrane Coloring Worksheet Cells Worksheet Cell Membrane Structure. ... Schematic Diagram Of A Cell Membrane Plasma Membrane Cell Membrane Cell Membrane Structure. ... Cell Membrane Coloring Worksheet Answer Key Cell Membrane Coloring Worksheet Cells Worksheet Cell Membrane. ... Membrane Best Of Diagram With Plasma Membrane Stock Vector Illustration Plasma Membrane Cell Membrane Cell Membrane Structure. ...
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Physical Studies of Cell Surface and Cell Membrane Structure. Deuterium Nuclear Magnetic Resonance Studies of N- ... Physical Studies of Cell Surface and Cell Membrane Structure. Deuterium Nuclear Magnetic Resonance Studies of N- ... Physical Studies of Cell Surface and Cell Membrane Structure. Deuterium Nuclear Magnetic Resonance Studies of N- ... Physical Studies of Cell Surface and Cell Membrane Structure. Deuterium Nuclear Magnetic Resonance Studies of N- ...
... a defining feature of membrane contact sites (MCSs) can give rise to the observed spatial organelle distribution. We devise a ... strategy will be of high value for characterizing the dynamics and function of MCSs between various organelles in living cells. ... or from the plasma membrane for production of oxysterols and steroid hormones. This process depends on the endo-lysosomal ... S1A for structures). In human fibroblasts lacking functional NPC2 (NPC2−/− cells), CTL accumulates in LE/LYSs after uptake from ...
... ... Natures fastest motors are the cochlear outer hair cells (OHCs). These sensory cells use a membrane protein, Slc26a5 (prestin ... structure constrains the mobility of plasma membrane proteins and that the integrity of such membrane-associated structures are ... All five proteins showed minimal diffusion, but did move after pharmacological disruption of membrane-associated structures ...
The module describes how the components and structure of cell membranes relate to key functions. ... This module explores how scientists came to understand cell membranes, including the experiments that led to the development of ... they are complex and dynamic structures that control what enters and leaves the cell. ... Cell membranes are much more than passive barriers; ... a. if cells were surrounded by membranes. Incorrect. b. if cell ...
... on the functional relevance and structural features of these proteins and how they are organized into a novel type of membrane ... Cell Membrane Structures / metabolism* * Exocytosis / physiology * Fertilization / physiology * Humans * Membrane Fusion / ... Annu Rev Cell Dev Biol. 2003:19:397-422. doi: 10.1146/annurev.cellbio.19.111301.153609. ... From structure and mutagenesis studies, we are beginning to understand functional subregions within tetraspanins, as well as ...
The cell membrane is semi-permeable, meaning that it allows certain substances to move into the cell while it keeps ... as well as the cells organelles) within it, separating the interior of the cell from the outside environment. ... The cell membrane is a thin membrane that encases the cytoplasm of the cell, and holds the cytoplasm ( ... decreasing the size of the cell membrane and the cell itself.. The Structure Of The Cell Membrane. The cell membrane consists ...
... everything you need for studying or teaching Cell membrane. ... Immediately download the Cell membrane summary, chapter-by- ... Membrane Structure Surrounding each cell within the nervous system is a highly complex lipid bilayer called a membrane formed ... Membrane Cell membranes or plasma membranes surround cells, separating the cytoplasm and organelles on the inside from the ... Cell membrane Summary. Everything you need to understand or teach Cell membrane. ...
In eukaryotic cells complex membrane structures called organelles are highly designed. In eukaryotic cells complex membrane ... At required occasions, cells were washed in PBS?, fixed in 4% (wt/vol) paraformaldehyde for 15 min and stored in water at 4C ... This has resulted in the speculation that NO travels as retrograde messenger in the post- towards the presynaptic cell (Schuman ... Prior computational types of metastases have centered on tumor cell growth in a bunch environment, or prediction of metastasis ...
across cell membranes. . These channels transport positively charged potassium atoms (ions) out of cells. The movement of ... Mutations in these genes alter the usual structure and function of potassium channels or prevent the assembly of normal ... which means both copies of the gene in each cell have mutations. Most often, the parents of a child with an autosomal recessive ... potassium ions through these channels is critical for maintaining the normal functions of inner ear structures. and cardiac ...
Cell membranes need to change their shapes during many cellular processeslike protein trafficking, cytokinesis and membrane ... Cryo-electronmicroscopy (cryoEM) has emerged as a powerful tool to visualize proteinsat the membrane interface. Here, we ... The formation ofinvaginations (or tubules) is regulated by the composition of negativecharged lipids in membrane bilayer or ... Therefore electrostatic interactions regulate recruitment andcrowding of BIN1; and consequently membrane deformation.Second, we ...
The flagellar secretion apparatus comprises a membrane-embedded complex of about five proteins, and soluble factors, which ... apparatus that is related to the type III secretion system used by many pathogens to transfer effector proteins into host cells ... a specialized secretion apparatus that functions to deliver the protein subunits that form the filament and other structures to ... is related to the injectisome used by many gram-negative pathogens and symbionts to transfer effector proteins into host cells ...
... abnormal membrane structure, disruption of zinc homeostasis, and an increase in myocardial superoxide dismutase activity ( ... Int J Biochem Cell Biol. 2017 Aug. 89:125-35. [QxMD MEDLINE Link]. [Full Text]. ... The myocyte mitochondria in the hearts of persons exposed to alcohol are clearly abnormal in structure, and many believe that ... In addition, it provides information not only on overall heart size and function, but on valvular structure and function, wall ...
Cell Membrane - Cell Wall Biology Parts of a Cell The structure and composition of the cell membrane and of cell wall. ... muscle cell structure 65 videos. * Muscle Contraction AP Biology AP Biology Videos Muscle cell structure Sarcomere structure ... Plant Structure Biology Plants The structure of plants.. plant structure stem structure epidermis cortex endodermis vascular ... Parts of a Cell AP Biology AP Biology Videos Membrane structure endosymbiosis organelles protein synthesis ...
2011) Crystal structure of the mammalian GIRK2 K+ channel and gating regulation by G proteins, PIP2, and sodium. Cell 147:199- ... PI(4,5)P2 makes clusters on neuronal cell membranes in mouse cerebellum. How PI(4,5)P2 is distributed across cell membrane ( ... 9C). These results suggest the ubiquitous association of CaV2.1 with PI(4,5)P2 in neuronal cell membranes across various cell ... Previous studies demonstrated that PI(4,5)P2 forms clusters of 50-100 nm in diameter on the cell membrane of PC12 cells (Aoyagi ...
Cell Membrane Structure and Function For Teachers 9th - 12th Standards Teach your class how to get out of a cell - or break in ... Basic Cell Structure For Teachers 7th Initially, general details about cells and single cell organisms are provided. Next, the ... Your students will love this PowerPoint! Great visuals will support understanding of membrane proteins, cell membranes, active ... plasma membranes cover cells to do the same. Scholars begin with a presentation that gives overview of the structure and ...
Membrane-electrode structures for molecular catalysts for use in fuel cells and other electrochemical devices Patent Kerr, John ... The ECP can be coupled to a hydroxide exchange membrane fuel cell (HEMFC) that is disclosed herein as a fuel cell system. These ... The ECP can be coupled to a hydroxide exchange membrane fuel cell (HEMFC) that is disclosed herein as a fuel cell system. These ... Cell structure for electrochemical devices and method of making same patent, June 1993 * Kaun, Thomas D. ...
Structure and Function of Cell Membrane... The Rockefeller University * Yifan Cheng, PhD Investigator Determining the 3D ... Membrane Dynamics (3) Apply Membrane Dynamics filter *Membrane Proteins (12) Apply Membrane Proteins filter ...
Cell envelope and membrane structure and synthesis. Bacterial growth, cell division and coordination mechanisms. Control of DNA ... This module provides an up to date understanding of how fundamental research in bacterial cell biology helps to elucidate ... The lecture sequence will comprise of a module introduction followed by lectures on specific aspects of bacterial cell biology ... central biological questions such as the control and regulation of cell division and of gene expression in bacteria. It will ...
Copyright © 2023, Structure Probe, Inc. - All Rights Reserved. ... Cells can be grown on the membrane just as they would on ... West Cell Kit with 50 nm thick membranes, 0.5mm window, Pack of 10. West Cell Kit with 50 nm thick membranes, 0.5mm window, ... Wet Cell™ Kits. Each kit contains ten membrane grids of the stated membrane thickness plus 10 blanks to make a total of 10 ... the thinner the membrane the more likely one might be to rupture the membrane. Therefore we offer the Wet Cell Kits in a ...
Cell envelope and membrane structure and synthesis. Bacterial growth, cell division and coordination mechanisms. Control of DNA ... This module provides an up to date understanding of how fundamental research in bacterial cell biology helps to elucidate ... The lecture sequence will comprise of a module introduction followed by lectures on specific aspects of bacterial cell biology ... central biological questions such as the control and regulation of cell division and of gene expression in bacteria. It will ...
PFA uses short electrical pulses to disrupt cell membranes. The novelty is that it is cardioselective and does not affect ... adjacent structures, such as the phrenic nerve or esophagus. Many European centers have adopted PFA. It may not improve ...
... ribosomal structure and biogenesis; [K] transcription; [L] replication, recombination and repair; [M] cell wall/membrane/ ... ribosomal structure and biogenesis; [K] transcription; [L] replication, recombination and repair; [M] cell wall/membrane/ ... COG letters are defined as follows: [C] energy production and conversion; [D] cell cycle control, cell division, chromosome ... ribosomal structure and biogenesis, and cell wall formation according to the COG database (Supplementary Table 2 and ...
  • The complex consists of a continuous network of membrane-limited tubules which originate as invaginations of the apical plasma membrane at the base of the microvilli, some associated vesicles, and a giant vacuole. (
  • Cells are enclosed by a plasma membrane composed of lipids and proteins. (
  • Plasma membrane is the outermost covering of the cell that separates the contents of the cell from its external environment. (
  • Mitochondria receive cholesterol from late endosomes and lysosomes (LE/LYSs) or from the plasma membrane for production of oxysterols and steroid hormones. (
  • We now understand that the plasma membrane is a very dynamic part of the cell and that is much more than just a barrier. (
  • Plasma Membrane The plasma membrane is a very thin, continuous sheet of phospholipids and proteins that surrounds all living cells and separates them from their external environment. (
  • PI(4)P is enriched in the membrane of the Golgi apparatus and synaptic vesicles (SVs), PI(4,5)P 2 and PI(3,4,5)P 3 mainly exist in the plasma membrane, PI(3)P and PI(3,5)P 2 are selectively concentrated on early and late endosomes, respectively. (
  • 세포막(cell membrane) 또는 원형질막(plasma membrane)은 끊임없이 변화하는 풍경과 같습니다. (
  • It mediates fusion of synaptic vesicles with the presynaptic plasma membrane resulting in exocytosis of neurotransmitters. (
  • In eukaryotic cells complex membrane structures called organelles are highly designed to exert specialized functions. (
  • The description of eukaryotic cells. (
  • Unlike the lipid-based membranes of eukaryotic cells, bacterial microcompartments (BMCs) have polyhedral shells made of proteins. (
  • Studies of the action of anesthetic molecules led to the theory that this barrier might be made of some sort of fat (lipid), but the structure was still unknown. (
  • This "flaw" remained unanswered for nearly half a century until the discovery that specialized molecules called integral membrane proteins can act as ion transportation pumps. (
  • The outer layer of a cell, or a cell membrane, is a complex structure with many different kinds of molecules that are in constant motion, moving fluidly throughout the membrane. (
  • Cell membranes form selective barriers that protect the cell from the watery environment around them while letting water-insoluble molecules like oxygen, carbon dioxide and some hormones pass through. (
  • Yes, it does restrict many molecules from entering (or leaving) the cell, but it is also designed so that some molecules can very quickly move through the membrane, and thus enter or leave the cell with ease. (
  • Glycoproteins are proteins that have a carbohydrate chain linked to them, and they assist cells in communicating with other cells and transporting molecules across the cell membrane. (
  • Transport proteins, as the name implies, are responsible for transporting molecules through the cell membranes and into the body of the cell through the process of facilitated diffusion. (
  • Membrane Structure Surrounding each cell within the nervous system is a highly complex lipid bilayer called a membrane formed by microscopic phospholipid molecules. (
  • Membrane Fluidity The membranes of bacteria function to give the bacterium its shape, allow the passage of molecules from the outside in and from the inside out, and to prevent the internal contents f. (
  • Study biologically important molecules including DNA, RNA and proteins, as well as the molecular events that govern cell function. (
  • Our BSc Molecular Biology course focuses on the structure and function of biologically important molecules, giving you a range of theoretical knowledge and practical lab skills. (
  • For lipid-based membranes, there are membrane proteins that get molecules across. (
  • The study authors said that by using the structural data from this paper, researchers can design experiments to study the mechanisms for how the molecules get across this protein membrane, and to build custom organelles for carbon capture or to produce valuable compounds. (
  • Hydrophobic regions of membrane proteins, normally embedded in the membrane lipid bilayer, are now surrounded by a layer of detergent molecules and the hydrophilic regions are exposed to the aqueous medium. (
  • Major histocompatibility complex class I (MHC I) molecules present antigenic peptides to cytotoxic T cells to eliminate infected or cancerous cells. (
  • BioChemistry focuses on understanding the chemical basis which allows biological molecules to give rise to the processes that occur within living cells and between cells, which in turn relates greatly to the study and understanding of tissues and organs, as well as organism structure and function. (
  • The chemistry of the cell also depends on the reactions of smaller molecules and ions. (
  • My research interests are in the study of the basis and function of the heterogeneity of enzyme molecules and its role within the cell. (
  • The phospholipids of the cell. (
  • Most of the cell membrane is formed by phospholipids that have a unique structure that causes them to self-arrange into a double layer that is hydrophobic in the middle and hydrophilic on the outside. (
  • A component of the lipids in animal cells is cholesterol, which is dispersed in between the phospholipids and parts of the membrane. (
  • Biological membranes consist of phospholipids that contain two hydrophobic groups connected to a polar head. (
  • Phospholipids are a particular type of lipid that make up much of the structure of cell membranes. (
  • Young, healthy animals have a specific combination of phospholipids in their cell membranes, which are continually replenished. (
  • While Olsen doesn't think age-related changes in the production of phospholipids or the resulting degradation of the cell membranes lead to cancer, she did note that certain lipids found in cell membranes can impact cancer treatment options, such as drug delivery methods. (
  • According to their view, this protein coat had no particular structure and was simply formed by adsorption from solution. (
  • Their theory was also incorrect in that it ascribed the barrier properties of the membrane to electrostatic repulsion from the protein layer rather than the energetic cost of crossing the hydrophobic core. (
  • those of protein transport recent studies using yeast as a model system began to provide intriguing insights into phospholipid exchange between the ER and mitochondria as well as between the mitochondrial outer and inner membranes. (
  • Bacterial flagella contain a specialized secretion apparatus that functions to deliver the protein subunits that form the filament and other structures to outside the membrane 1 . (
  • Cell membranes need to change their shapes during many cellular processeslike protein trafficking, cytokinesis and membrane homeostasis. (
  • Here, we employed transmission electronmicroscopy and other biophysical methods to elucidate how BAR domainproteins steer processes at the membrane.In this work we studied the BAR protein bridging integrator 1 (BIN1), whichhas an established role in cancer, Alzheimer's disease and skeletalmyopathies. (
  • Thisimplies that BIN1 rather bundles actin than decorates single filaments.Third, we explored a strategy to purify an aggregation prone BAR protein.Aggregation is a property common in Peripheral Membrane Proteins. (
  • The discovery of the gene sequences and predicted protein structures, role of CCR5 alleles has prompted studies of but their ligands have not been identified the possible role of many other host genes in (orphan receptors). (
  • Scientists are providing the clearest view yet of an intact bacterial microcompartment, revealing at atomic-level resolution the structure and assembly of the organelle's protein shell. (
  • The contents within these organelles determine their specific function, but the overall architecture of the protein membranes of BMCs are fundamentally the same, the authors noted. (
  • For BMCs, the shell is already made of proteins, so the shell proteins of BMCs not only have a structural role, they are also responsible for selective substrate transfer across the protein membrane. (
  • 세포는 많은 종류의 막 단백질(membrane protein)을 함유하고 있으며 (적혈구는 50가지 이상을 함유하고 있습니다) 세포 유형에 따라 다양한 군의 막 단백질을 함유하고 있습니다. (
  • Common applications include cell lysis, solubilization of membrane proteins and lipids, protein crystallization, and reduction of background staining in blotting experiments. (
  • Even though studying membrane proteins is a major challenge in protein biochemistry, they remain an important area of study due to their significant biological and pharmacological relevance. (
  • Membrane solubilization by detergents can be described as a three stage process where the detergent-lipid-protein ratio is an important factor ( Figure 3 ). (
  • Excess detergent is normally employed in solubilization of membrane proteins to ensure complete dissolution of the membrane and provide a large number of single protein molecule containing micelles. (
  • They are present in all cells in the body and consist of DNA and a supporting structure of protein. (
  • New technologies for purifying membrane-bound protein complexes in combination with cryo-electron microscopy (EM) have recently allowed the exploration of such complexes under near-native conditions. (
  • In particular, polymer-encapsulated nanodiscs enable the study of membrane proteins at high resolution while retaining protein-protein and protein-lip. (
  • The peripheral membrane proteins are only linked to the membrane through interactions with different proteins, they are exterior and not part of the membrane itself. (
  • However, from studies of prototype tetraspanins, information regarding functions, cell biology, and structural organization has begun to emerge. (
  • Challenge your biology class to analyze an experimental setup, in which a selectively permeable membrane separates two distinct solutions. (
  • This module provides an up to date understanding of how fundamental research in bacterial cell biology helps to elucidate central biological questions such as the control and regulation of cell division and of gene expression in bacteria. (
  • The lecture sequence will comprise of a module introduction followed by lectures on specific aspects of bacterial cell biology. (
  • You will learn about DNA, RNA and proteins and the molecular events that govern cell function while exploring the relevant aspects of biochemistry, genetics and cell biology. (
  • The Pathology Department conducts research into anatomical and clinical correlations in human pathology, and in the fields of cell biology, general immunology and immunopathology. (
  • Detergents are widely used in biochemistry, cell biology and molecular biology. (
  • From the intricate molecular world inside our cells to how our body systems work and the dynamic interactions between organisms and their environment, A-level Biology is the study of life in all its rich complexity. (
  • A series of pioneering experiments in 1925 indicated that this barrier membrane consisted of two molecular layers of lipids-a lipid bilayer. (
  • In spite of these issues the fundamental conclusion- that the cell membrane is a lipid bilayer- was correct. (
  • When low concentrations of a detergent are added to biological membranes (a), the detergent monomers (shown in red with single tails) perturb the membrane structurally by partitioning into the lipid bilayer (b). (
  • Endocytosis serves the opposite function, removing proteins and lipids from the cell membrane and bringing them into the interior of the cell, decreasing the size of the cell membrane and the cell itself. (
  • Four membrane faces are revealed by fracturing frozen membranes of the apical tubules and vesicles: two complementary inner membrane faces exposed by the fracturing process and the lumenal and cytoplasmic membrane surfaces revealed by etching. (
  • β-Cells depend on the islet basement membrane (BM). (
  • Immunostained sections were assessed for airway smooth muscle (ASM) area, subepithelial basement membrane thickness, nerve fibers, and epithelial neuroendocrine cells. (
  • Thus, by the early twentieth century the chemical, but not the structural nature of the cell membrane was known. (
  • It took several more decades before scientists came to understand the structural features of the membrane that allow it to repel water. (
  • This review summarizes key aspects of tetraspanin proteins, with a focus on the functional relevance and structural features of these proteins and how they are organized into a novel type of membrane microdomain. (
  • Structural proteins enable our cells to maintain a constant shape and gives the cell support, much as the skeleton of an animal's body does. (
  • Having the full structural view of the bacterial organelle membrane can help provide important information in fighting pathogens or bioengineering bacterial organelles for beneficial purposes. (
  • Sterols play a unique role for the structural and dynamical organization of membranes. (
  • Conclusion: BT is a treatment option in patients with severe therapy-refractory asthma that downregulates selectively structural abnormalities involved in airway narrowing and bronchial reactivity, particularly ASM, neuroendocrine epithelial cells, and bronchial nerve endings. (
  • Describe components of a cell including cell membrane and cytoplasm 3. (
  • Thin barrier separating inside of cell cytoplasm from outside environment Function. (
  • The cell membrane is a thin membrane that encases the cytoplasm of the cell , and holds the cytoplasm (as well as the cell's organelles) within it, separating the interior of the cell from the outside environment. (
  • Membrane Cell membranes or plasma membranes surround cells, separating the cytoplasm and organelles on the inside from the extracellular fluid on the outside. (
  • The availability of cholesterol constitutes the rate-limiting step of steroidogenesis and is regulated by STARD1 which transfers cholesterol from the outer to the inner mitochondrial membrane 5 . (
  • Infoldings of the inner mitochondrial membrane. (
  • He also noted that a thin film of oil behaves as a semipermeable membrane, precisely as predicted. (
  • They use a thistle tube and a semipermeable membrane to. (
  • Bulk flow of water through a semipermeable membrane into another aqueous compartment containing solute at a higher concentration. (
  • The cell membrane also helps regulate the growth of the cell, by controlling the processes of exocytosis and endocytosis . (
  • Exocytosis has vesicles that contain lipids and proteins combine with the cell membrane, which has the effect of increasing the overall size of the cell. (
  • Flagellar assembly begins with structures in the cytoplasmic membrane and proceeds through steps that add the exterior structures in a proximal-to-distal sequence ( Fig. 1 ) 1 . (
  • CM, cytoplasmic membrane. (
  • SIGNIFICANCE STATEMENT In this study, we established an electron microscopic method to visualize and analyze the quantitative distribution pattern of phosphatidylinositol-4,5-bisphosphate (PI(4,5)P 2 ) on cell membranes using cryo-fixed brain tissues and SDS-digested freeze-fracture replica labeling. (
  • By combining these materials with a 3D bioprinting technique, it is possible to fabricate intricate structures responsive to an external magnetic stimulus, thus allowing the tuning of the constructs properties to better recapitulate the microarchitecture of native tissues. (
  • Structure and function of the human body including cells, tissues and membranes. (
  • This uses this link and covers the following topics- Cell membrane structure- Function of the different parts of a cell membrane- Diffusion- Faci. (
  • The process of cell diffusion. (
  • Great visuals will support understanding of membrane proteins, cell membranes, active transport, and diffusion. (
  • Cell theory has its origins in seventeenth century microscopy observations, but it was nearly two hundred years before a complete cell membrane theory was developed to explain what separates cells from the outside world. (
  • The microcompartment shell provides a selectively permeable barrier which separates the reactions in its interior from the rest of the cell. (
  • The peri-islet membrane, which encapsulates the islets, separates the endocrine cells from the exocrine pancreas and serves as a barrier from immune cell infiltration to the islets. (
  • Our quantitative imaging strategy will be of high value for characterizing the dynamics and function of MCSs between various organelles in living cells. (
  • Although the cell membrane is the most well-known membrane in a cell, some of the organelles found within a cell also have their own respective membranes. (
  • Examples of organelles with their own membranes include vacuoles, lysosomes , and the Golgi apparatus. (
  • Integral membrane proteins are those which are part of the membrane itself and are capable of passing through the membrane. (
  • 1 These integral membrane proteins (IMPs) ( Figure 2 ) are not soluble in aqueous solutions as they aggregate to protect their hydrophobic domains, but are soluble in detergent solutions as micelles formed by detergents are analogous to the bilayers of the biological membranes. (
  • PI(4,5)P 2 interacts with various ion channels and receptors to regulate membrane signaling but its nanoscale distribution and association with these proteins remain elusive. (
  • Thus, we hypothesized that pericytes regulate β-cells through the production of BM components. (
  • We further found that the pericytic laminin isoforms differentially regulate mouse β-cells. (
  • The outer membrane face reveals a distinct array of membrane particles. (
  • Combined data from sectioned, negatively stained, and freeze-etched preparations indicate that this regular particulate structure is a specialization that is primarily localized in the outer half of the membrane mainly in the outer leaflet. (
  • From the time cells were first discovered in the mid-1600s, scientists knew that there must be some sort of outer wrapping around the cell to hold the contents of the cell together. (
  • Although it was too thin for them to see with simple light microscropes, scientists called this outer wrapping a membrane (in Latin, membrana ), which means a thin layer of skin or tissue. (
  • From the 17th century until around the 1960s, the outer membrane of cells was thought to be a simple passive barrier. (
  • They interpreted this as meaning that to pass the cell membrane a molecule must be at least sparingly soluble in oil, their "lipoid theory of narcosis. (
  • The NS1 structures reveal distinct domains for membrane association of the dimer and interactions with the immune system and are a basis for elucidating the molecular mechanism of NS1 function. (
  • To obtain information about BIN1's interaction with themembrane in near native environments, we used artificial lipid systems suchas liposomes and lipids nanotubes.First, we have shown that electrostatic interactions are more important forBIN1 when binding to membranes with low curvature. (
  • It consists of 40 multiple choice questions on everything from the structure of DNA to the interactions within. (
  • However, while many studies demonstrated the importance of the ECM, its interactions with β-cells are still not fully understood. (
  • The interactions with the various BM components differentially affect β-cells, although the underlying mechanism is largely unknown. (
  • Much of BioChemistry deals with the structures, functions, and interactions of biological macromolecules, such as proteins, nucleic acids, carbohydrates, and lipids, which provide the structure of cells and perform many of the functions associated with life. (
  • Prokaryotic Membrane Transport The ability of Prokaryotic microorganisms to move compounds into the cell, and to remove waste products of metabolism out of the cell, is crucial for the survival of the. (
  • The mechanisms by which cells harness energy from their environment via chemical reactions are known as metabolism. (
  • The repeating unit is an ∼7.5-nm diameter particle which has a distinct subunit structure composed of possibly nine smaller particles each ∼3 nm in diameter. (
  • This method revealed PI(4,5)P 2 clusters preferentially accumulated in specific membrane compartments and its distinct associations with Ca V 2.1, GIRK3, and mGluR1α in the mouse cerebellum. (
  • Influence of membrane composition on the enhancement of factor VIIa/tissue factor activity by magnesium ions. (
  • Traube had no direct evidence for the composition of this film, though, and incorrectly asserted that it was formed by an interfacial reaction of the cell protoplasm with the extracellular fluid. (
  • The formation ofinvaginations (or tubules) is regulated by the composition of negativecharged lipids in membrane bilayer or electrostatic residues on the BARdomain. (
  • The structure and composition of the cell membrane and of cell wall. (
  • She is exploring whether scientists can create lipid replacement treatments to alter the lipid composition in membranes to improve how well cells absorb and use medications. (
  • By the 19th century it was accepted that some form of semi-permeable barrier must exist around a cell. (
  • The plant cell wall was easily visible even with these early microscopes but no similar barrier was visible on animal cells, though it stood to reason that one must exist. (
  • As previously mentioned, the cell membrane serves as a barrier that can open to allow certain needed substances into the cell while keeping other substances outside of the cell. (
  • These membranes form a barrier that protects cells and impacts their normal functions, like producing energy and absorbing nutrients. (
  • The e- PTFE membrane showed better results and appeared more adequate for GBR therapy, forming a barrier to prevent the migration of connective tissue into the extraction socket. (
  • Cell Structure and Function Worksheet Answer Key are an Excel worksheet that makes it easy to create a cell structure and function worksheet. (
  • Cell structure and function worksheet answer key by using suitable subjects. (
  • Cell Structure and Function Worksheet Answer Key. (
  • Cell membranes were thought to be passive barriers until the 1960s, but we now know that they are active and responsive structures that serve a critical function as gatekeepers and communicators. (
  • Therefore the primary function of the ERMES as the phospholipid transport machinery is still under argument although its membrane tethering function is now widely recognized. (
  • Mutations in these genes alter the usual structure and function of potassium channels or prevent the assembly of normal channels. (
  • Dashed boxes indicate the proteins that function in flagellar secretion, either in the membrane-bound part of the apparatus or in delivery of substrate. (
  • The structure and function of nerve cells. (
  • Since the early years of the HIV epidemic, cell function, have been suggested to explain significant differences in the rate of disease these findings (7,10,11,15). (
  • Thus, alongside ECs, pericytes are a significant source of the islet BM, which is essential for proper β-cell function. (
  • Understanding the structure and function of membrane proteins requires their careful isolation in the native form in a highly purified state. (
  • The neuroblastoma cell line SH-SY5Y is commonly employed to study neuronal function and disease. (
  • to include (but not limited to) the structure and function of the central and peripheral nervous systems. (
  • They are small enough to cross membrane barriers. (
  • It is possible to find different techniques using physical barriers 2-7 and the characteristics of the biomaterial and the design of the membrane used in guided tissue regeneration play an important role in obtaining good results 8 . (
  • Expanded polytetrafluoroethylene (e-PTFE) membranes have been the standard materials for clinical treatment with guided bone regeneration (GBR), achieving good results when used as mechanical barriers covering sites of extraction e- PTFE is a polymer with high stability in biological systems, which provides better tissue organization, infection resistance and no induction of inflammatory reactions 1 . (
  • e-PTFE membranes are used as mechanical barriers to protect the blood clot and allow bone cells to be selected to repopulate the bone defect, preventing the epithelial tissue to migrate into the defect 1 . (
  • Therefore, the aim of GBR to exclude soft tissue with the use of barriers in such a way that only bone cells populate the region to be regenerated. (
  • In particular, the impact of α-spinasterol on the structure and organization of lipid membranes was investigated and compared with those of cholesterol. (
  • Furthermore, we revealed extensive association of PI(4,5)P 2 with Ca V 2.1 and GIRK3 across different membrane compartments, whereas its association with mGluR1α was compartment specific. (
  • Therefore we offer the Wet Cell Kits in a selection of different membrane thickness and we leave it to our customers to decide which is best for them. (
  • We also offer a "sampler" kit that includes 2 each of four different membrane thicknesses (e.g. 100 nm, 50 nm, 30 nm and 20 nm) plus 8 "blanks" so that there would be enough material to make a total of 8 different Wet Cells. (
  • The cell membrane is semi-permeable, meaning that it allows certain substances to move into the cell while it keeps certain other substances out of the cell. (
  • Bleb Expansion in Migrating Cells Depends on Supply of Membrane from Cell Surface Invaginations. (
  • The lumenal surface of this tubular network of membranes and associated vesicles is covered with a regular repeating particulate structure. (
  • These linear aggregates, when arranged laterally, give rise to several square and oblique two-dimensional lattice arrangements of the particles which cover the surface of the membrane. (
  • When they compared the area of the monolayer to the surface area of the cells, they found a ratio of two to one. (
  • Later analyses of this experiment showed several problems including an incorrect monolayer pressure, incomplete lipid extraction and a miscalculation of cell surface area. (
  • Some of the functions of the cell membrane include protecting and enclosing the cell giving shape to the cell allowing transportation of materials in and out of the cell and carry out metabolic reactions near the inner surface of the cell membrane. (
  • Physical Studies of Cell Surface and Cell Membrane Structure. (
  • Dive into the research topics of 'Physical Studies of Cell Surface and Cell Membrane Structure. (
  • Glycolipids are found on the surface of the cell membrane, and they have carbohydrate sugars attached to them. (
  • Molecular Mechanisms of Membrane Transporter. (
  • Even though the exact insight mechanisms of how ascitic fluid exert to ovarian cancer cells is poorly defined, my research suggests that ascitic fluid can increase expression of oncogenic proteins in ovarian cancer cells and reduce the cellular uptake of targeted drugs. (
  • Since the invention of the microscope in the seventeenth century it has been known that plant and animal tissue is composed of cells : the cell was discovered by Robert Hooke. (
  • IMs are found in the space between the tissue stroma cells and contain, among other components, fibrillar collagens and fibronectin. (
  • Receptor tyrosine kinases including EGFR, HER-2 and c-Met and non receptor tyrosine kinase including Jaks are selectively expressed in primary tissue and metastatic tumour of advanced ovarian cancer cells. (
  • A cell of nervous tissue specialized for transmission of a nerve impulse. (
  • They have been recorded in haemolymph, in muscle tissue and inside cells. (
  • It is the core structure of the tissue. (
  • To investigate the amount of connective tissue migrated into the extraction socket using EPTFE and latex membranes. (
  • However, care should be taken during placement because exposure of the membrane during the healing of the bone defect can lead to significant a decrease in bone tissue regeneration 9 . (
  • This technique is based on Melcher's 10 (1970) observation that the type of tissue formed in a given area depends on the type of cells populating that area. (
  • Vacuoles and lysosomes use a membrane to encase a variety of different substances for transport or, in the case of the lysosome, elimination. (
  • Although the results of this experiment were accurate, Fricke misinterpreted the data to mean that the cell membrane is a single molecular layer. (
  • What allows things through a membrane is pores," said study lead author Markus Sutter, MSU senior research associate and affiliate scientist at Berkeley Lab's Molecular Biophysics and Integrated Bioimaging (MBIB) division. (
  • A professor at Worcester Polytechnic Institute (WPI) is exploring aging on the molecular level, examining how the lipids found in our bodies, particularly those in our cell membranes, change as we age, and how those changes may affect our propensity for age-related diseases, including Alzheimer's disease. (
  • The current study reports data on the membrane properties of the phytosterol (3β,5α,22 E )-stigmasta-7,22-dien-3-β-ol (α-spinasterol), which represents an important component of argan oil and have not been investigated so far in molecular detail. (
  • Stages in the solubilization of biological membranes by detergents. (
  • To understand these factors, I am using three dimensional (3D) cell cultures, chicken embryos and a syngeneic mouse model to investigate the biological activity in ovarian cancer. (
  • Despite wealth information of these tyrosine kinase expressions and activation, little is known about the biological activity of tyrosine kinases in ovarian cancer cells are present in ascitic fluid. (
  • In recent years, a few studies have started to investigate the biological activity of ascitic fluid,which is believed to influence behavior of ovarian cancer cells. (
  • Because the biological structures and processes she is studying are common in all animals, her work with C. elegans has implications for human health and aging. (
  • Cell Membrane Structures" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (
  • Together with Syntaxin-1A and SNAP25, it forms the core membrane fusion machinery that is responsible for neurotransmitter release and, therefore, signal transmission between neurons. (
  • These branched structures are able to pick up impulses(messages) from many other neurons. (
  • These clusters show preferential accumulation in specific membrane compartments of different cell types, in particular, in Purkinje cell (PC) spines and granule cell (GC) presynaptic active zones. (
  • However, this method has insufficient spatial resolution to observe the nanoscale PIs distribution in small membrane compartments, such as presynaptic active zones (AZs) and postsynaptic densities (PSDs). (
  • The SNARE complex assembles from vesicular Synaptobrevin-2 as well as Syntaxin-1 and SNAP25 both anchored to the presynaptic membrane. (
  • Receptor proteins are those which enable the cell to communicate with things in the environment, achieving this to the use of neurotransmitters and hormones. (
  • One major discovery was that members of the chemokine receptor family serve as cofactors for HIV entry into cells. (
  • However, for further physicochemical and biochemical characterization of membrane proteins, it is often necessary to remove the unbound detergent. (
  • This resting potential is determined by the concentration gradients of 2 major ions, Na + and K + , and the relative membrane permeability to these ions (also known as leak currents). (
  • contain enzymes and other components required for specialized cell functions. (
  • Substrates must diffuse within the cell to interact with their enzymes. (
  • The aqueous contents of a cell or organelle (the mitochondrion, for example) with dissolved solutes. (
  • But more importantly, it provides the very first picture of the shell of an intact bacterial organelle membrane. (
  • Frequent vacuolation and loss of pseudopodia and microvilli from the membrane were observed. (
  • Using Markov Chain Monte Carlo image simulations, we show that interaction between both organelle types, a defining feature of membrane contact sites (MCSs) can give rise to the observed spatial organelle distribution. (
  • These membranes help protect the organelle from the other chemical functions going on in the cell, separating their components from the rest of the cell. (
  • The simultaneous transport, by a single transporter, of two solutes across a membrane. (
  • Olsen, the Leonard P. Kinnicutt Assistant Professor of Chemistry and Biochemistry, says the key to healthy aging could lie with the maintenance of membranes over time, affecting the health of cell membranes. (
  • Phosphoinositides (PIs) are minor components on the cytoplasmic side of eukaryotic cell membranes, but they play essential roles in a wide variety of cellular functions. (
  • While some islet BM components are produced by endothelial cells (ECs), the source of others remains unknown. (
  • In addition to providing biomechanical support to the islets, ECM components are required for β-cell development, proliferation, survival, and proper insulin secretion. (
  • Thus, human endocrine cells are not in direct contact with the vascular BM components but with the invaginated peri-islet membrane. (