Canadian Medical Guide > Biological Sciences > Biochemical Phenomena, Metabolism, and Nutrition > Biochemical Phenomena Terms and Definitions
Biochemical Phenomena
Medical Definition: | Biochemical functions, activities, and processes at organic and molecular levels in humans, animals, microorganisms, and plants. |
Guide Notes: | GEN or unspecified; prefer specifics; BIOLOGICAL PHENOMENA is also available; DF: BIOCHEM PHENOMENA |
Previously Indexed: | Biochemistry (1966-1997) |
Acid-Base Equilibrium - The balance between acids and bases in the BODY FLUIDS. The pH (HYDROGEN-ION CONCENTRATION) of the arterial BLOOD provides an index for the total body acid-base balance. | |
Aerobiosis - Life or metabolic reactions occurring in an environment containing oxygen. | |
Allosteric Regulation | |
Anaerobiosis - The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed) | |
Base Composition - The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid. | |
Binding Sites - The reactive parts of a macromolecule that directly participate in its specific combination with another molecule. | |
Body Composition - The relative amounts of various components in the body, such as percent body fat. | |
Brain Chemistry | |
Calcification, Physiologic - Process by which organic tissue becomes hardened by the physiologic deposit of calcium salts. | |
Diffusion - The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space; a major mechanism of BIOLOGICAL TRANSPORT. | |
Energy Transfer - The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed). In biochemistry, this concept generally refers to the transfer of groups from compounds that contain energy-rich bonding arrangements to compounds that have relatively energy-poor bonding characteristics via thermodynamically permissible enzymatic reactions. This principle is a major premise of the interaction between energy-producing and energy-utilizing metabolic pathways in living cells. (From Devlin, Textbook of biochemistry with clinical correlations, 3d ed, p246) | |
Enzyme Activation - Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1) activation by ions (activators); 2) activation by cofactors (coenzymes); and 3) conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme. | |
Fermentation - An enzyme-induced chemical change in organic compounds that takes place in the absence of oxygen. The change usually results in the production of ETHANOL or LACTIC ACID, and the production of energy. | |
Ion Transport - The movement of ions across energy-transducing cell membranes. Transport can be active, passive or facilitated. Ions may travel by themselves (uniport), or as a group of two or more ions in the same (symport) or opposite (antiport) directions. | |
Membrane Fluidity - 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. | |
Molecular Conformation - The characteristic three-dimensional shape of a molecule. | |
Molecular Mimicry - The process in which structural properties of an introduced molecule imitate or simulate molecules of the host. Direct mimicry of a molecule enables a viral protein to bind directly to a normal substrate as a substitute for the homologous normal ligand. Immunologic molecular mimicry generally refers to what can be described as antigenic mimicry and is defined by the properties of ANTIBODIES raised against various facets of EPITOPES on the viral protein. (From Immunology Letters 1991 May;28(2):91-9) | |
Molecular Structure - The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds. | |
Nitrosation - Conversion into nitroso compounds. An example is the reaction of nitrites with amino compounds to form carcinogenic N-nitrosamines. | |
Nucleic Acid Denaturation - Disorganization of secondary structures of nucleic acids through cleavage of hydrogen bonds and hydrophobic linkages. Denatured DNA appears to be a single-stranded flexible structure. The effects of denaturation on RNA are similar though less pronounced and largely reversible. | |
Nucleic Acid Renaturation - The reformation of all, or part of, the native conformation of a nucleic acid molecule after the molecule has undergone denaturation. | |
Osmosis - Tendency of fluids (e.g., water) to move from the less concentrated to the more concentrated side of a semipermeable membrane. | |
Protein Binding - 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. | |
Protein Denaturation | |
Protein Folding - A rapid biochemical reaction involved in the formation of proteins. It begins even before a protein has been completely synthesized and proceeds through discrete intermediates (primary, secondary, and tertiary structures) before the final structure (quaternary structure) is developed. | |
Protein Hybridization - The formation of a protein consisting of two or more polypeptide chains from separate and different polypeptide chains. | |
Protein Renaturation - The reconstitution of a protein's activity following denaturation. | |
RNA Stability - The extent to which an RNA molecule retains its structural integrity and resists degradation by RNASES, and base-catalyzed HYDROLYSIS, under changing in vivo or in vitro conditions. | |
Sequence Homology - The degree of similarity between sequences. Studies of amino acid and nucleotide sequences provide useful information about the genetic relatedness of certain species. | |
Structure-Activity Relationship - The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups. Other factors contributing to structure-activity relationship include chemical reactivity, electronic effects, resonance, and inductive effects. | |
Substrate Specificity - A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts. | |
Water-Electrolyte Balance - The balance of fluid in the BODY FLUID COMPARTMENTS; total BODY WATER; BLOOD VOLUME; EXTRACELLULAR SPACE; INTRACELLULAR SPACE, etc., maintained by processes in the body that regulate the intake and excretion of WATER and ELECTROLYTES, particularly SODIUM and POTASSIUM. |
Biochemical Phenomena Medical Definitions and Terms
|
Wildlife On Video »
Canada's Great Outdoors
Tour Canadian Rockies »
Book Banff »
Book Jasper »
Maligne Lake Boat Cruise »
Gondola Banff »
Hike Jasper »
Jasper Columbia Icefield »