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27 Cards in this Set
- Front
- Back
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What are enzymes?
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Large molecules that increase the rates of chemical reactions without themselves undergoing any change.
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The vast majority of all known enzymes are what type of protein?
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globular proteins
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What are ribozymes?
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Enzymes that are made of ribonucleic acids.
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List the six major groups enzymes are classified into:
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- oxidoreductases
- transferases - hydrolases - lyases - isomerases - ligases |
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What type of reaction do oxidoreductases catalyze?
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They catalyze oxidations and reductions.
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What type of reaction do transferases catalyze?
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They catalyze the transfer of a group of atoms, such as from one molecule to another.
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What type of reaction do hydrolases catalyze?
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They catalyze hydrolysis reactions.
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What type of reaction do lyases catalyze?
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They catalyze the addition of two groups to a double bond or the removal of two groups from adjacent atoms to create a double bond.
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What type of reaction do isomerases catalyze?
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They catalyze isomerization reactions.
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What type of reaction do ligases/synthetases catalyze?
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They catalyze the joining of two molecules.
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What is a cofactor?
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The nonprotein part of an enzyme necessary for its catalytic function.
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What is an apoenzyme?
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The protein (polypeptide) portion of the enzyme.
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What types of ions are cofactors?
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They can be Mg2+, Zn2+, or they can be organic such as Vitamin B.
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What are coenzymes?
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They are organic cofactors.
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An apoenzyme cannot catalyze a reaction without its _____.
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An _____cannot catalyze a reaction without its cofactor.
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What is the substrate?
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The compound on which the enzyme works and whose reaction it speeds up.
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What is the active site?
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It is where the substrate binds to the surface of the enzyme while it undergoes the reaction.
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What is an inhibitor?
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A compound that binds to an enzyme and lowers its activity.
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What is the difference between a competitive and a noncompetitive inhibitor?
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Competitive inhibitors bind to the active site of the enzyme, preventing the binding of the substrate.
Noncompetitive inhibitors bind elsewhere on the enzyme and work by altering the tertiary structure of the enzyme so its catalytic effectiveness is eliminated. |
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What is the enzyme-substrate complex?
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The intermediate in an enzyme-catalyzed reaction.
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Which five amino acids are most commonly found at active sites?
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- histidine
- cysteine - aspartic acid - arginine - glutamic acid |
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What is a nucleophilic attack?
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A chemical reaction where and electron-rich atom, such as oxygen or sulfur, bonds to an electron-deficient atom, such as carbonyl carbon.
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What is feedback control?
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An enzyme regulation process in which formation of a product inhibits an earlier reaction in the sequence.
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What is a proenzyme?
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Also called a zymogen, it is a protein that becomes an active enzyme after undergoing a chemical change.
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What is allosterism?
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The regulation of an enzyme by binding a regulator molecule to a site on the enzyme other than the active site. It can inhibit or stimulate the enzyme action.
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What is protein modification?
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It is the process of affecting the enzyme activity by covalently modifying the enzyme.
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In 1817, what President was the first to have his inauguration outdoors?
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James Monroe, in front of the Old Brick Capitol (1st and A NE, present site of Supreme Court, while Capitol was being rebuilt after War of 1812)
[Note: This was held outdoors by necessity, not choice. The first President to choose to have a large, outdoor public inauguration on the East Portico of the Capitol was Andrew Jackson.] |
