Cofactor: An inorganic molecule or ion that helps an enzyme carry out its function, #KAPLAN

Competitive Inhibition: A decrease in enzyme that results from the interaction of an inhibitor with the active site of an enzyme; competitive inhibition can be overcome by addition of excess substrate. #KAPLAN

Conformational Coupling: A less-accepted mechanism of ATP synthase activity in which the protons cause a conformational change that releases ATP from ATP synthase. #KAPLAN

Conjugated Protein: A protein that derives part of its function from cobpvalently attached molecules (prosthetic groups). #KAPLAN

Corepressor: A species that binds with a repressor, allowing the complex to bind to the operator region of an operon, stopping transcription of the relevant gene. #KAPLAN

Cristae: Infoldings of the inner mitochondrial membrane that increase the surface area available for electron transport chain complexes. #KAPLAN

Degenerate: Description of the generic code, in which more than one codon can specify a single amino acid. #KAPLAN

Denaturation: The loss of tertiary structure in a protein, leading to loss of function. #KAPLAN

Deoxyribonucleic Acid (DNA): A nucleic acid found exclusively in the nucleus that codes for all the of the genes necessary for life; transcribed to mRNA and always read 5' to 3". #KAPLAN

Desmosomes: Cell-to-cell junctions that anchor layers of epithelial cells to one another. #KAPLAN

Disulfide Bond: A covalent interaction between the -SH groups of two cysteine residues; an element of tertiary and quaternary structure. #KAPLAN

Electrochemical Gradient: An uneven separation of ions across a biological membrane, resulting in electrical potential energy. #KAPLAN

Electrophoresis: The process of separating compounds on the basis of size and charge using a porous gel and an electric field ; protein electrophoresis generally uses polyacrylamide, while nucleic acid electrophoresis generally uses agarose. #KAPLAN

Elongation: The three-step cycle repeated for each amino acid being dded to a protein during translation. #KAPLAN

Endocytosis: The transport of molecules into a cell through invagination of the cell membrane and the formation of the vesicle; phagocytosis is the endocytosis of solids, pinocytosis is the endocytosis of liquids. #KAPLAN

Enhancer: A collection of several response elements that allow for the control of one gene's expression by multiple signals. #KAPLAN

Enzyme: A biological molecule with catalytic activity; includes many proteins and some RNA molecules. #KAPLAN

Epimers: A subtype of diasteromers that differ in absolute configartion at exactly one chiral carbon. #KAPLAN