Question

1. In allosteric enzyme inhibition, the active site is blocked by another molecule

a. True

b. False

2. In the second-messenger system of hormonal action,

a. The presence of a small amount of one hormone (the second messenger) is essential to permit another hormone (the first messenger) to exert its full effect.

b. A tropic hormone (the first messenger) stimulates secretion of another hormone (the second messenger).

c. The hormone first binds to a specific surface receptor (the first messenger), whereupon the hormone-receptor complex moves into the cell to combine with a specific intracellular receptor (the second messenger).

d. Releasing hormones (the first messenger) from the hypothalamus regulate the release of many anterior pituitary hormones (the second messenger).

e. The combination of a hormone (the first messenger) with membrane surface receptors activates adenylyl cyclase, which catalyzes the transformation of cellular ATP to cyclic AMP, which in turn acts as a “second messenger” to produce alteration of cell function associated with that hormone.

3. Which is NOT a product at the completion of Kreb’s Cycle?

a. NADH

b. FADH2

c. Pyruvate

d. Carbon Dioxide

e. ATP

4. In many second messenger mechanisms calcium binds to ______ and together they form a complex which activates various enzyme systems.

a. Adenylyl cyclase

b. G proteins

c. Calmodulin

d. IP3

e. All of the above

5. ________ is the principle enzyme that is responsible for the synthesis of an RNA transcript that ultimately becomes part of a ribosome?

a. RNA Polymerase II

b. RNA polymerase III

c. DNA Polymerase

d. RNA Polymerase I

e. DNA Primase

Answer 1

In allosteric enzyme inhibition the active site is blocked by another molecule.:- True

In the second messenger system of harmonal action A tropic harmone (the first messanger) stimulate the secretion of another harmone.

Which is not a product at the completion of the of Krebs cycle?:- Pyruvate

In many second messenger mechanisms calcium bind to Calmodulin and together they form a complex which activates various enzyme systems.

RNA polymerase II Is the principle enzyme that is responsible for the synthesis of an RNA transcript that ultimately becomes part of a ribosome?