Questions and answers for exam Preparation

MCQs

Total Questions : 101 | Page 3 of 11 pages

Question 21. When visual stimulus reaches receptors in retina of eye, second process involving absorption of physical energy by receptors is?

Reception
Transduction
Coding
Adaptation

Discuss Question

Answer: Option B. -> Transduction
Answer: (b).Transduction

Question 22. How does Ras oncogene contribute to cancers?

It codes for an anti-apoptotic protein, produced in abnormally large amounts
It codes for a GTPase switch protein, which in its mutated form cannot be switched off
It codes for a transcription factor produced abnormally in large amounts
A growth factor that is continually active is encoded in its truncated form

Discuss Question

Answer: Option B. -> It codes for a GTPase switch protein, which in its mutated form cannot be switched off
Answer: (b).It codes for a GTPase switch protein, which in its mutated form cannot be switched off

Question 23. Oncogenes do not encode for ___________

Trans-membrane protein receptors
Growth factors
DNA-dependent RNA polymerase
Cytoplasmic G-proteins and protein kinases

Discuss Question

Answer: Option C. -> DNA-dependent RNA polymerase
Answer: (c).DNA-dependent RNA polymerase

Question 24. Programmed cell death is termed as ___________

Metastasis
Apoptosis
Proliferation
Mitotic termination

Discuss Question

Answer: Option B. -> Apoptosis
Answer: (b).Apoptosis

Question 25. Which of the following could be coded by a tumor-supressor gene?

A protein that helps prevent progression through cell cycle
A protein that helps prevent apoptosis
A protein that codes for a DNA repair enzyme
A protein that forms part of a growth factor signaling pathway

Discuss Question

Answer: Option A. -> A protein that helps prevent progression through cell cycle
Answer: (a).A protein that helps prevent progression through cell cycle

Question 26. Proto-oncogenes can be transformed to oncogenes by all of the following mechanisms except _____________

Elimination of their start signals for translation
During a viral infection cycle
Chromosomal rearrangements
Chemically induced mutagenesis

Discuss Question

Answer: Option A. -> Elimination of their start signals for translation
Answer: (a).Elimination of their start signals for translation

Question 27. Which of the following statements is true about transmembrane electrical potential?

The chemical gradient drives Cl⁻ and K⁺ inwards
The electrical gradient drives Na⁺ and Ca⁺² inwards
The chemical gradient drives Na⁺ and Ca⁺² inwards and K⁺ outward
The chemical gradient drives Cl⁻ and K⁺ outwards

Discuss Question

Answer: Option C. -> The chemical gradient drives Na⁺ and Ca⁺² inwards and K⁺ outward
Answer: (c).The chemical gradient drives Na⁺ and Ca⁺² inwards and K⁺ outward

Question 28. The receptor channels for which of the following are gated by extracellular ligands?

Glycine
IP₃
cAMP
cGMP

Discuss Question

Answer: Option A. -> Glycine
Answer: (a).Glycine

Question 29. Nicotinic acetylcholine receptor is an example of _____________

Ligated gated receptor channel
Serpentine receptors
Adhesion receptors
Receptor enzymes

Discuss Question

Answer: Option A. -> Ligated gated receptor channel
Answer: (a).Ligated gated receptor channel

Question 30. Which of the following statements is false about a ligand-gated ion channel receptor?

They are present in the cell membrane
They consist of five glycoproteins
Differences in membrane potential affect whether the channel receptors are open or close
Neurotransmitters can act as the chemical messengers for these channels

Discuss Question

Answer: Option C. -> Differences in membrane potential affect whether the channel receptors are open or close
Answer: (c).Differences in membrane potential affect whether the channel receptors are open or close