BIO 201 Homework 4

Rank these reactions from least to most energetically favorable.

1. Glucose to Glucose-6-P, +3.3kcal/mol 2. Glucose-6-P to Fructose-6-P, +0.4kcal/mol 3. ATP to ADP and Pi, -7.3kcal/mol 4. PEP to pyruvate, -14.8kcal/mol

Molecules capable of enzymatic activity include...

RNA and proteins

What happens to sucrase when it binds to sucrose?

Sucrase goes through a conformational change.

A mutation occurred in the gene that encodes the enzyme sucrase, resulting in a single amino acid substitution in the active site of the enzyme; a polar amino acid changed to a nonpolar amino acid. What is probably the result of this mutation.

Sucrase will not be able to bind sucrose in the active site

If thiamine pyrophosphate was not available to the enzyme in the animation which of the following would occur?

The enzyme would not be able to cleave pyruvate.

Based on the animation, which of the following observations is true?

The product from one reaction served as the substrate for the next reaction.

L-Arabinose is a naturally occurring, non-caloric sweetener that is a non-competitive inhibitor of sucrase. If L-Arabinose is consumed, what will happen to the Vmax of the reaction and Km of the substrate?

Vmax will decrease, but Km will not change

Consider the biochemical pathway used to synthesize the amino acid proline. A large increase in the level of proline will most likely lead to

a decrease in proline production.

The enzyme in the animation is most likely catalyzing _____.

an anabolic reaction

Your body needs amino acids to build new proteins encoded by your genes. Many of these amino acids come from your diet through the ____ of proteins you eat.v

catabolism

An enzyme binds the product more tightly than the substrate.

false

An enzyme catalyzes a chemical reaction in the cell, but can only be used once.

false

If the end product of the biochemical pathway in the animation increases it would eventually result in an increase in substrate 2.

false

In the example shown, which best describes the role of thiamine pyrophosphate in the reaction to cleave pyruvate?

it behaves like a catalyst and is not consumed in the reaction

Enzymes catalyze reactions by

lowering activation energy.

How often can a sucrase molecule be used to hydrolyze sucrose?

many times

Enzymes are

proteins

Which of the following binds most tightly to the active site of an enzyme?

substrates

In feedback inhibition, the inhibitor of the biochemical pathway is often

the final product of the biochemical pathway.

What function do many B vitamins serve in the production of energy?

they function as co-enzymes

An enzyme may catalyze a reaction by stressing or destabilizing the bonds of the substrates. This point in the enzymatic reaction is known as the

transition state

If the end product of the biochemical pathway in the animation increases it would eventually result in an increase in substrate 1.

true

In a biochemical pathway, the product released by the first enzyme becomes the substrate for the second enzyme.

true

Sucrase uses ____ to cleave sucrose into two monosaccharides.

water