BIOL1406 Week 5 Exercise

Substrates are held in the active site of an enzyme by:

the matching shape of the allosteric site.

hydrogen and ionic bonds.

the action of coenzymes and cofactors.

the lowering of the activation energy.

hydrogen and ionic bonds.

The location on an enzyme that binds substrate is its:

cofactor.

active site.

allosteric site.

tertiary structure.

active site.

Hydrogen peroxide (H2O2) is a toxic byproduct of aerobic respiration in cells. The reaction shown helps prevent hydrogen peroxide buildup in cells.

2H2O2 -> 2H2O + O2

In this reaction, catalase (above the yield arrow) functions as an:

emuisifier in the digestion of hydrogen peroxide.

enzyme in the breakdown of hydrogen peroxide.

indicator to detect hydrogen peroxide.

enzyme in the synthesis of hydrogen peroxide.

enzyme in the breakdown of hydrogen peroxide.

How does an enzyme catalyze a reaction?

by changing the equilibrium of a spontaneous reaction

by decreasing the amount of energy released by a reaction

by decreasing the energy of activation for a chemical reaction

by supplying the energy to speed up a reaction

by increasing the amount of free energy of the reaction

by decreasing the energy of activation for a chemical reaction

Cells must produce many different enzymes because:

rate of production of enzymes is important in regulating energy production by cells.

enzymes are degraded quickly.

most cellular reactions require a specific, unique enzyme.

enzymes aare generally ineffective at speeding up reactions.

most cellular reactions require a specific, unique enzyme.

What happens to an enzyme when it denatures?

destruction of disulfide bonds between cystein residues

destruction of peptide bonds

loss of three dimensional shape of the molecule

nothing

loss of three dimensional shape of the molecule

Names of enzymes typically end with:

-ol.

-ose.

-ase.

-ine.

-ase.

Which of the following statements regarding enzymes is true?

Enzymes are permanently altered by the reactions they catalyze.

Enzymes change the direction of a chemical reaction.

Enzymes increase the rate of reaction.

Enzymes have no effect on the rate of a reaction.

Enzymes prevent changes in substrate concentrations from having an effect on reaction rates.

Enzymes increase the rate of reaction.

Which of the following enzymes would be important in fat digestion?

lipase

amylase

protease

lactase

lipase

Which of the following explains the concept of saturation?

The enzyme has been degraded.

All of the active sites of the enzymes are occupied.

There is no more substrate.

The reaction has come to a stop because of the buildup of product.

All of the active sites of the enzymes are occupied.

The inactive form of an enzyme is a(n):

apoenzyme

zymogen

holoenzyme

apogen

zymogen

In the degradation of maltose to two glucose molecules:

the enzyme, maltase, is the subtrate.

maltose is the product.

water is the substrate.

maltose is the subtrate.

maltase is the product.

maltose is the subtrate.

The organic nonprotein portion of an enzyme that is required for proper function is a(n):

enzyme.

apoenzyme.

coenzyme.

allosteric enzyme.

coenzyme.

Which of the following activities would result in an increase the rate of a chemical reaction?

cooling the reactants

decreasing the concentration of reactants

increasing the activation energy

adding a catalyst

increasing entropy

adding a catalyst

When guaiacol reacts with peroxide and peroxidase, it is ______________ to tetraguaiacol, resulting in the formation of a color compound that can be detected spectrophotometrically.

oxidized

reduced

oxidized

Control of enzyme activity is an important aspect of regulating cell metabolism. Which of the following is LEAST likely to be a mechanism of controlling enzyme activity?

denaturation

reversible inhibition

cooperativity

feedback inhibition

allosteric regulation

denaturation

If the substrate concentration is limiting, how does increasing enzyme concentration affect reaction rate?

Increasing enzyme concentration decreases reaction rate.

Increasing enzyme concentration results in an increase in reaction rate.

Increasing enzyme concentration has no effect on reaction rate.

Increasing enzyme concentration has no effect on reaction rate.

The experimental setup for your lab involved the extraction of an enzyme from turnip, and observing its reaction rate under a variety of conditions. What is the enzyme?

peroxidase

guaiacol

hydrogen peroxide

hydrolase

peroxidase

Vitamins are essential to the survival of organisms because vitamins usually function as:

catalysts.

substrates.

coenzymes.

nucleic acids.

coenzymes.