Definitions Flashcards
(335 cards)
Absolute configuration
The nomenclature system used for the three-dimensional arrangement of atoms in
isomers; the most common systems are D/L and (R)/(S).
Acetal
A carbon atom bonded to an alkyl group, two - OR groups, and a hydrogen.
Acetyl-CoA
An important metabolic intermediate that links glycolysis and B-oxidation to the citric acid cycle; can also be converted into ketone bodies.
Activation
The conversion of a biomolecule to its active or usable form, such as activation of tRNA with an amino acid or activation of a fatty acid with CoA to form fatty acyl-CoA .
Activation energy
The energy required to change the state of a molecule or group of molecules to the transition state; the energy required for a reaction to occur.
Active site
The catalytically active portion of an enzyme.
Active transport
The movement of a molecule against its concentration gradient with energy investment; primary active transport uses ATP, whereas secondary active transport
uses a favorable transport gradient of a different molecule.
Activity
The measure of the catalytic activity of an enzyme, also called the velocity or rate. It is often measured as a vmax and may be analyzed after protein isolation.
Activity analysis
The determination of the enzymatic activity of an isolated protein by interaction with a substrate; usually colorimetric in nature.
Adenosine triphosphate (ATP)
The primary energy molecule of the body; it releases energy by breaking the bond with the terminal phosphate to form ADP and inorganic phosphate.
Adipocyte
A cell specializing in fat storage.
Aerobic respiration
A collection of energy-producing metabolic processes that require oxygen, including the citric acid cycle, electron transport chain, and oxidative phosphorylation.
Agglutination
Clumping of particles caused by the binding of antibody to target antigen.
Aldose
A sugar in which the highest order functional group is an aldehyde; can be categorized by number of carbons (triose, tetrose, pentose, hexose, etc.).
Allosteric enzymes
Enzymes that experience changes in their conformation as a result of interactions at sites other than the active site, called allosteric sites; conformational changes may increase or decrease enzyme activity.
Alpha helix
An element of secondary structure, marked by clockwise coiling of amino acids around a
central axis.
Alternative splicing
The production of multiple different but related mRNA molecules from a single primary transcript of hnRNA.
Amino acid
A dipolar compound containing an amino group (- NH2) and a carboxyl group (-COOH).
Amphipathic
Having both hydrophilic and hydrophobic regions.
Amphoteric
The ability to act as an acid or base.
Amplification
Increased transcription (and translation) of a gene in response to hormones, growth factors, and other intracellular conditions.
Anabolism
The series of metabolic processes that result in the consumption of energy and the synthesis of molecules.
Anaerobic respiration
The series of energy-producing metabolic processes that do not require oxygen, including glycolysis and fermentation.
Anomers
A subtype of epimers in which the chiral carbon with inverted configuration was the carbonyl carbon (anomeric carbon).