A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
The property of blood capillary ENDOTHELIUM that allows for the selective exchange of substances between the blood and surrounding tissues and through membranous barriers such as the BLOOD-AIR BARRIER; BLOOD-AQUEOUS BARRIER; BLOOD-BRAIN BARRIER; BLOOD-NERVE BARRIER; BLOOD-RETINAL BARRIER; and BLOOD-TESTIS BARRIER. Small lipid-soluble molecules such as carbon dioxide and oxygen move freely by diffusion. Water and water-soluble molecules cannot pass through the endothelial walls and are dependent on microscopic pores. These pores show narrow areas (TIGHT JUNCTIONS) which may limit large molecule movement.
Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.
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).
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.
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.
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.
Software used to locate data or information stored in machine-readable form locally or at a distance such as an INTERNET site.
The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.
Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.
A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.
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.
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
A species of the Beta genus. Cultivars are used as a source of beets (root) or chard (leaves).
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.
A group of FLAVONOIDS derived from FLAVONOLS, which lack the ketone oxygen at the 4-position. They are glycosylated versions of cyanidin, pelargonidin or delphinidin. The conjugated bonds result in blue, red, and purple colors in flowers of plants.
Any technique by which an unknown color is evaluated in terms of standard colors. The technique may be visual, photoelectric, or indirect by means of spectrophotometry. It is used in chemistry and physics. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Compounds derived from TYROSINE via betalamic acid, including BETAXANTHINS and BETACYANINS. They are found in the Caryophyllales order of PLANTS and some BASIDIOMYCETES.
Natural or synthetic dyes used as coloring agents in processed foods.
Conjugates of betalamic acid with cyclo-dopa, both of which derive from TYROSINE. They appear similar to INDOLES but are biosynthesized by a different path and contain N+. Members are red or violet COLORING AGENTS found in the Caryophyllales order of PLANTS and some BASIDIOMYCETES.
Conjugates of betalamic acid with AMINO ACIDS. Some of them are yellow COLORING AGENTS in the Caryophyllales order of PLANTS. This should not be confused with xanthin which is a term used for CAROTENES nor with XANTHINES.
Any spaces or cavities within a cell. They may function in digestion, storage, secretion, or excretion.
A plant genus of the family ANACARDIACEAE. This is the source of the familiar cashew nuts, which are heat treated to remove the irritant toxin. Cashew nut shell liquid (frequently abbreviated as CNSL) is a major source of alkenyl phenolic compounds, especially ANACARDIC ACIDS, cardol, and cardanol.
Solutions that have a greater osmotic pressure than a reference solution such as blood, plasma, or interstitial fluid.
Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed)
A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.
The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.
Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)
The outermost layer of a cell in most PLANTS; BACTERIA; FUNGI; and ALGAE. The cell wall is usually a rigid structure that lies external to the CELL MEMBRANE, and provides a protective barrier against physical or chemical agents.
Time period from 1601 through 1700 of the common era.
Time period from 1801 through 1900 of the common era.
The use of instrumentation and techniques for visualizing material and details that cannot be seen by the unaided eye. It is usually done by enlarging images, transmitted by light or electron beams, with optical or magnetic lenses that magnify the entire image field. With scanning microscopy, images are generated by collecting output from the specimen in a point-by-point fashion, on a magnified scale, as it is scanned by a narrow beam of light or electrons, a laser, a conductive probe, or a topographical probe.
Time period from 1701 through 1800 of the common era.