Biochemistry

Question: cAMP and cGMP are derived from
[A].

ATP and GTP by the actions of adenylate cyclase and guanylate cyclase respectively

[B].

GTP and ATP by the actions of adenylate cyclase and guanylate cyclase respectively

[C].

ATP and GTP by the actions of guanylate cyclase and adenylate cyclase respectively

[D].

none of the above

Answer: Option A

Explanation:

No answer description available for this question.

Question: The major second messengers are
[A].

cAMP

[B].

cGMP

[C].

DAG

[D].

All of these

Answer: Option D

Explanation:

No answer description available for this question.

Question: The binding of ligands to many G-proteins linked receptors leads to shortlived
[A].

increase in the concentration of certain intracellular signaling molecules called second messenger

[B].

decrease in the concentration of certain intracellular signaling molecules called second messenger

[C].

increase in the concentration of certain extracellular signaling molecules called first messenger

[D].

decrease in the concentration of certain extracellular signaling molecules called first messenger

Answer: Option A

Explanation:

No answer description available for this question.

Question: The hormone or ligand can be considered as
[A].

first messenger

[B].

second messenger

[C].

both (a) and (b)

[D].

none of these

Answer: Option A

Explanation:

No answer description available for this question.

Question: Which of the following comes under the category of cell surface receptor?
[A].

Enzyme linked receptors

[B].

Ion-channel linked receptors

[C].

G protein linked receptors

[D].

All of these

Answer: Option D

Explanation:

No answer description available for this question.

Question: Small charged molecules, often biogenic amines function as
[A].

hormones

[B].

neurotransmitters

[C].

both (a) and (b)

[D].

none of these

Answer: Option C

Explanation:

No answer description available for this question.

Question: The enzyme that catalyzes the splitting of PIP2 into two molecules of inositol triphosphate (IP3) and diacylglycerol in cell signaling, is
[A].

phosphokinase C

[B].

phospholipase C

[C].

phosphodiesterase C

[D].

lipokinase

Answer: Option B

Explanation:

No answer description available for this question.

Question: Which of the following statement is incorrect?
[A].

The principal lipophilic hormones that binds to receptors located in the plasma membranes are prostaglandins

[B].

Prostaglandins are synthesized from arachidonic acid

[C].

Prostaglandins act as paracrine signaling molecules

[D].

None of the above

Answer: Option D

Explanation:

No answer description available for this question.

Question: In paracrine signaling, the signaling molecules affects only
[A].

target cells close to the cell from which it was secreted

[B].

target cells distant from its site of synthesis in cells of an endocrine organ

[C].

both (a) and (b)

[D].

none of the above

Answer: Option A

Explanation:

No answer description available for this question.

Question: Cell signaling can be classified into
[A].

three distinct types based on the distance over which the signaling molecules act

[B].

two distinct types based on the distance over which the signaling molecules act

[C].

three distinct types based on the signaling molecules

[D].

none of the above

Answer: Option A

Explanation:

No answer description available for this question.