MCAT enzymes Exam Questions with Verified Answers

Enzyme - Answer-Biological catalyst Lower activation energy Increase rate of reaction Are not changed or consumed during reaction pH and temperature sensitive Do not affect overall Delta G Specific for a particular reaction or class of reactions Do not change equilibrium of a reaction Urease - Answer-Catalyzes the breakdown of urea Oxidoreductases - Answer-Catalyze oxidation-reduction reactions, transfer of electrons between biological molecules. Often require cofactors that acts as electron carrier, NAD+ or NADP+. The electron donor is the reductant Electron acceptor is oxidant Enzymes with dehydrogenase or reductant in their name are usually oxidoreductases Transferases - Answer-Catalyze the movement of a functional group from one molecule to another. Includes kinases Kinases - Answer-Transferase enzymes that catalyze the transfer of a phosphate group, generally ATP, to another molecule Hydrolases - Answer-Catalyze breaking of a compound into two molecules using the addition of water. Usually named only for substrate. Includes phosphatases, peptidases, nucleases, lipases Phosphatases - Answer-Catalyze the cleavage of a phosphate group from another molecule. Type of Hydrolase Peptidases - Answer-Catalyze breakdown of proteins. Type of hydrolase Nucleases - Answer-Catalyze breakdown of nucleic acids. Type of hydrolase Lipases - Answer-Catalyze breakdown of lipids. Type of hydrolase Lyases - Answer-Catalyze the cleavage of a single molecule into two products. Do not require water and do not act as Oxidoreductases. May also catalyze the synthesis of two molecules, usually a synthase