The genetic material in a retrovirus is: MCQ with Answer and Explanation

The genetic material in a retrovirus is:
A. Single-stranded DNA
B. Single-stranded RNA
C. Double-stranded DNA
D. Double-stranded RNA
Answer: Option B
Solution (By JKSSB Mock Tests)
Retroviruses (e.g., HIV) possess two copies of single-stranded RNA and the enzyme reverse transcriptase, which transcribes the RNA into DNA upon infection. This DNA integrates into the host genome. Other viruses may have dsDNA, ssDNA, or dsRNA, but the defining feature of retroviruses is the RNA genome and reverse transcription.

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Practice More Biology Questions

Question #1
The type of circulatory system in which blood is confined to vessels is called:
A. Lymphatic system
B. Portal system
C. Closed circulatory system
D. Open circulatory system

Correct Answer: Option C


Explanation:
In a closed circulatory system (e.g., humans, annelids, cephalopods), blood is always enclosed within vessels (arteries, veins, capillaries) and is distinct from interstitial fluid. Open systems (arthropods, most mollusks) have hemolymph bathing organs in sinuses. The lymphatic system returns fluid to blood. A portal system connects two capillary beds.

This question belongs to: Science Biology
Question #2
Consider the following statements about mutations:
1. Mutations can be caused by UV radiation.
2. All mutations result in a change in the protein sequence.
3. Mutations in germ cells are heritable.
Which of the above is/are correct?
A. 2 and 3 only
B. 1 and 3 only
C. 1 and 2 only
D. 1, 2, and 3

Correct Answer: Option B


Explanation:
UV radiation can induce mutations; germline mutations are passed on. Not all mutations change protein sequence (silent mutations). So 2 is incorrect.

This question belongs to: Science Biology
Question #3
The hormone that stimulates the production of red blood cells is:
A. Insulin
B. Thrombopoietin
C. Erythropoietin
D. Aldosterone

Correct Answer: Option C


Explanation:
Erythropoietin (EPO), produced mainly by the kidneys in response to low oxygen levels, stimulates the bone marrow to produce red blood cells. Insulin regulates glucose, thrombopoietin stimulates platelet production, aldosterone regulates sodium and potassium balance.

This question belongs to: Science Biology