Chapter 7: The Behavior of Proteins: Enzymes, Mechanisms, and Control

Which of the following amino acid side chains would best serve as a general acid, assuming the protein functions at a pH of 7? a) alanine b) aspartic acid c) lysine d) aspargine

c) lysine

Kinase reactions describe enzymes which: a) add phosphate groups to another molecule b) oxidize alcohols to aldehydes c) use NAD+/NADH in their reactions d) transfer groups from one part of a molecule to another. e) add or remove double bonds in molecules.

a) add phosphate groups to another molecule

Zymogens are: a) inactive precursors of enzymes which can be activated by the irreversible cleavage of covalent bonds b) inactive forms of enzymes which require phosphorylation by the kinase to become active c) allosteric enzymes that are always in the R state d) allosteric enzymes that are always in the T state

a) inactive precursors of enzymes which can be activated by the irreversible cleavage of covalent bonds

A transition-state analog is likely to bind to an enzyme: a) more tightly than the substrate b) less tightly than a substrate c) about as tightly as the substrate d) at a site other than the catalytic site

a) more tightly than the substrate

(Refer to the quiz, has a pathway) Which of the following would be an example of feedback inhibition? a) the product of the final reaction, F, interacting with E1. b) F interacting with an allosteric site in E4 c) B interacting with an allosteric site in E1 d) all of the intermediates or products in the reaction interacting with the activator site in E1.

a) the product of the final reaction, F, interacting with E1.

An important step in elucidating the behavior of an enzyme is: a) obtaining a crystalline same of the enzyme b) insuring that metal ions are always excluded from the enzyme sample c) determining the active site residues d) none of the above

c) determining the active site residues

The concerted and sequential models for the behavior of allosteric enzymes differ in: a) the conformational change in the enzyme in one model and not in the other. b) the number of predicted binding sites on the enzyme c)the manner which changes in the quaternary structure take place. d) the response of the enzyme to changes in temperature.

c)the manner which changes in the quaternary structure take place

Which of the following types of amino acids active is least likely to be involved in enzyme catalysis? a) Those with hydrophilic, neutral side-chains b) Those with negatively charged side-chains c) Those with positively charge side-chains d) Those with hydrocarbon side-chains

d) Those with hydrocarbon side-chains

Important mechanisms of enzymatic catalysis include: a) nucleophilic reactions b) general acid-base catalysis c) Lewis acid-base catalysis d) all of the above

d) all of the above

Which of the following is a mechanism of regulating enzyme activity? a) Feedback inhibition by product b) Addition or removal of phosphate groups from the enzyme. c) Presence of activators d) Activation of zymogens e) All of these regulate enzyme activity

e) All of these regulate enzyme activity