Enzymes: structure and properties

Стр 1 из 4Следующая ⇒

Lesson 4

Enzymes: structure and properties

Variant 1

1. The role of coenzymes is:

A. participation in enzymatic reaction;

B. interaction with activators and inhibitors;

C. formation of allosteric site;

D. responsible for specificity of enzymatic reaction.

2. The role of allosteric site is:

A. interaction with substrate molecules;

B. assembling on the membrane surface;

C. participation in enzymatic reaction;

D. interaction with activators and inhibitors.

3. What is the function of the hydrolases?

A. To catalyze racemization of optical or geometric isomers.

B. To catalyze cleavage of bonds by addition of water.

C. To catalyze transfer of C, N or P-containing groups.

D. To catalyze cleavage of C-C, C-S and certain C-N bonds.

4. The rate of an enzyme-catalyzed reaction is reduced by:

A. increasing the substrate concentration;

B. decreasing the pH to its optimum;

C. decreasing of substrate concentration;

D. increasing the pH to its optimum.

5. The active site of the complex enzyme is formed by:

A. components of cell membranes;

B. amino acid side chains of apoenzyme;

C. coenzyme;

D. molecules of substrate.

Lesson 4

Enzymes: structure and properties

Variant 2

1. The active site of the complex enzyme is formed by:

E. components of cell membranes;

F. amino acid side chains of apoenzyme;

G. coenzyme;

H. molecules of substrate.

2. Oxidoreductases:

A. catalyze reactions of optical or geometric isomers;

B. catalyze cleavage of disulfide bonds;

C. catalyze cleavage of bonds by addition of water;

D. none of the above.

3. The role of allosteric site is:

A. interaction with substrate molecules;

B. assembling on the membrane surface;

C. participation in enzymatic reaction;

D. interaction with activators and inhibitors.

4. All of the following statements about enzymes are true EXCEPT:

A. enzymes catalyze only direct reaction;

B. enzymes speed up chemical reaction;

C. enzymes are not used in chemical reaction;

D. enzymes catalyze a direct and a reverse reaction.

5. Enzymes are catalysts of protein's nature. They are:

A. highly specific in nature;

B. temperature liable;

C. active in pH optimum;

D. all of the above.

12 3 4 Следующая ⇒