Types of Enzymes quiz #1 Flashcards
Types of Enzymes quiz #1
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What are the six major classes of enzymes, and what type of reaction does each class catalyze?
The six major classes of enzymes are: 1) Oxidoreductases, which catalyze oxidation-reduction (redox) reactions by transferring electrons; 2) Transferases, which transfer functional groups between molecules; 3) Hydrolases, which catalyze hydrolysis reactions by breaking bonds with the addition of water; 4) Isomerases, which rearrange atoms within a molecule to form isomers; 5) Lyases, which form or break bonds without redox reactions or water, often creating or removing double bonds or rings; and 6) Ligases, which use energy (like ATP) to covalently join two molecules together. What mnemonic can help you remember the six major classes of enzymes?
The mnemonic 'Over the Hill' helps you remember the six major classes: Oxidoreductases, Transferases, Hydrolyases, Isomerases, Lyases, and Ligases. What type of reaction do oxidoreductases catalyze, and what is a classic example?
Oxidoreductases catalyze oxidation-reduction (redox) reactions by transferring electrons between molecules; a classic example is lactate dehydrogenase. How can you use the mnemonic 'LEO the lion goes GER' to determine which molecule is oxidized or reduced?
'LEO' stands for 'Lose Electrons is Oxidation' and 'GER' stands for 'Gain Electrons is Reduction,' so the molecule losing electrons is oxidized and the one gaining electrons is reduced. What do transferases do, and what is an example of a transferase enzyme?
Transferases catalyze the transfer of functional groups between molecules; an example is alanine transaminase, which transfers an amino group from alanine to alpha-ketoglutarate. What reaction do hydrolyases (hydrolases) catalyze, and what is a common example?
Hydrolyases catalyze hydrolysis reactions, breaking bonds by adding water; trypsin, which cleaves peptide bonds after lysine or arginine, is a common example. How do isomerases function, and what is an example of an isomerase in glycolysis?
Isomerases rearrange atoms within a molecule to form isomers; triose phosphate isomerase, which converts dihydroxyacetone phosphate to glyceraldehyde-3-phosphate, is an example. What distinguishes lyases from other enzyme classes, and what is a typical reaction they catalyze?
Lyases form or break bonds without redox reactions or water, often creating or removing double bonds or rings; pyruvate decarboxylase, which converts pyruvate to acetaldehyde and CO2, is a typical example. What is the main function of ligases, and what is a biological example?
Ligases use energy (like ATP) to covalently join two molecules together; DNA ligase, which joins DNA fragments during replication, is a biological example. How do enzymes help reactions 'get over the hill' in terms of energy?
Enzymes lower the activation energy of reactions, stabilizing the transition state and making it easier for reactions to proceed.
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