Biochemistry Mock Test 5

10%

Question 1 of 10

1. The binding of ligands to many GPCRs leads to ___________

Decrease in concentration of certain extracellular signal molecules called first messengers

Decrease in concentration of certain intracellular signal molecules called second messengers

Increase in concentration of certain intracellular signal molecules called second messengers

Increase in concentration of certain extracellular signal molecules called first messengers

Question 1 of 10

Question 2 of 10

2. At the end of each phase of cell cycle cyclins activating Cdks in that phase are inactivated irreversibly by _____________

De-phosphorylation

Destabilizing by proteolysis in a proteosome

Ubiquitinylation

Multiple phosphorylations

Question 2 of 10

Question 3 of 10

3. Bacteria do not have which of the following receptors?

GPCR

Nuclear steroid receptors

Adhesion receptors

Membrane proteins

Question 3 of 10

Question 4 of 10

4. Receptor proteins that indirectly activate enzymes that generate intracellular second messengers are _____________

Receptor enzymes

Steroid receptors

Serpentine receptors

Adhesion receptors

Question 4 of 10

Question 5 of 10

5. Which of the following statements regarding cyclins is not correct?

They can become linked to ubiquitin

They are activated and degraded during cell cycle

They catalyze the phosphorylation of protein

They contain a specific amino acid sequence that target them for proteolysis

Question 5 of 10

Question 6 of 10

6. At which cell cycle checkpoint, cell cycle is halted if cell’s DNA is damaged?

G₂ - M

G₁ - S

S - G₂

G₀ - G₁

Question 6 of 10

Question 7 of 10

7. Objects are perceived by photo receptors because rods or cones

Repolarize

Depolarize

Polarize

Hyperpolarize

Question 7 of 10

Question 8 of 10

8. Which drug is used to terminate early pregnancies?

RU486

Metformin

Victoza

Glucophage

Question 8 of 10

Question 9 of 10

9. Passage of a cell through stages of cell cycle is controlled by a protein kinase that phosphorylates many different proteins at appropriate times.

Tyrosine kinase

Cdk activating kinase

Cyclin-dependent kinase

Cyclins

Question 9 of 10

Question 10 of 10

10. cAMP and cGMP are derived from ____________

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

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

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

None of the mentioned

Question 10 of 10