Biochemistry Mock Test 5

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Question 1 of 10

1. How do steroid hormones produce their effects in cells?

By binding to intracellular receptors and promoting transcription of specific genes

By activating translation of certain m-RNAs

By activating key enzymes in metabolic pathway

By promoting the degradation of specific m-RNAs

Question 1 of 10

Question 2 of 10

2. Which is an example of negative regulator?

Nuclear receptors

CAP

Lac 1 gene

Phosphorylated STAT proteins

Question 2 of 10

Question 3 of 10

3. Which of the following converts GTP to cGMP to start its enzymatic cascade?

Protein kinase-A

Calmodulin

Receptor adenylyl cyclase

Receptor guanylyl cyclase

Question 3 of 10

Question 4 of 10

4. Depolarization and repolarization changes that occur during the action potential are produced by ____________

Negative feedback loops

Active transport pumps along the neuron membrane

Simple diffusion of ions down their concentration gradient

Carrier mediated transport

Question 4 of 10

Question 5 of 10

5. Which out of the following statements is true about G-protein couple receptors?

There are more extracellular loops than intracellular loops

The binding region for G-protein involves 2 extracellular loops

It contains 5 trans-membrane hydrophobic sections

The N-terminal chain is extracellular and C-terminal chain is intracellular

Question 5 of 10

Question 6 of 10

6. SH₂ domain specifically binds to _____________

Phosphorylated tyrosine residues

Phosphorylated serine residues

Ca⁺²

GDP

Question 6 of 10

Question 7 of 10

7. Which of the following occurs in meiosis but not in mitosis?

Replication of DNA prior to start of cell division

Separation of sister chromatids at anaphase

Attachment of spindle fibers to kinetochore

Pairing of homologous chromosomes at metaphase plate

Question 7 of 10

Question 8 of 10

8. Signal molecule fits the binding site on its complementary receptor called as _____________

Amplification

Cooperativity

Integration

Specificity

Question 8 of 10

Question 9 of 10

9. Which of the following about Rb tumor suppressor protein is correct?

It is activated when phosphorylated by Cdk

When a mitogenic signal is received, it binds the transcription factor E2F and thus stimulates the cell to enter S phase

It binds E2F transcription factor and prevents cell from entering S phase until a mitogenic signal is received

It is a transcription factor

Question 9 of 10

Question 10 of 10

10. Which out of the following is not involved in signal transduction by β-adrenergic receptor pathway?

cAMP

cGMP

GTP

ATP

Question 10 of 10