Chapter 9-2 Homework

Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's

Activation energy

Which major class of macromolecule included almost every enzyme found in the cell?

Proteins

Allosteric enzyme regulation is usually associated with

an enzyme with more than one subunit

The activation site of an enzyme is the region that

binds the substrate and is involved in the catalytic reaction of the enzyme

How does a noncompetitive inhibitor decrease the rate of an enzyme reaction?

by binding to another part of an enzyme other than the active site, causing the enzyme to change shape and making the active site less effective

How does a competitive inhibitor decrease the rate of an enzyme reaction?

by binding to directly to the active site of the enzyme

What is true regarding enzymes?

Enzymes increase the rate of a reaction by lowering the activation energy barrier.

According to the induced fit hypothesis of enzyme catalysis, what is true?

The binding of the substrate changes the shape of the enzyme's active site

What is an example of cooperativity?

a molecule binding at one unit of a tetramer, allowing faster binding at each of the other three

If an enzyme in solution is saturated with substrate, the most effective way to obtain a faster yield of products is to

add more of the enzyme

Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as a(n)

cofactor necessary for the enzyme activity

The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as

feedback inhibition

Some of the drugs used to treat HIV patients are competitive inhibitors of the HIV reverse transcriptase enzyme. Unfortunately, the high mutation rate of HIV means that the virus rapidly acquires mutations with amino acid changes that make them resistant to these competitive inhibitors. Where in the reverse transcriptase enzyme would such amino acid changes most likely occur in drug-resistant viruses?

in or near the active site

A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because

the activation energy barrier for this reaction cannot be surrounded

Some bacteria are metabolically active in hot springs because

their enzymes have high optimal temperatures