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

The genetic material in a retrovirus is:
A. Single-stranded RNA
B. Single-stranded DNA
C. Double-stranded DNA
D. Double-stranded RNA
Answer: Option A
Solution (By JKExamLibrary)
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 scientist who proposed the 'one gene-one enzyme' hypothesis was:
A. Meselson and Stahl
B. Hershey and Chase
C. Beadle and Tatum
D. Watson and Crick

Correct Answer: Option C


Explanation:
George Beadle and Edward Tatum, working with Neurospora crassa, proposed that each gene controls the synthesis of a specific enzyme (later refined to one gene-one polypeptide). Watson and Crick discovered DNA structure, Hershey-Chase confirmed DNA as genetic material, Meselson-Stahl demonstrated semi-conservative replication.

This question belongs to: Science Biology
Question #2
Which of the following is a nitrogen-fixing bacterium in legume roots?
A. Rhizobium
B. Azotobacter
C. Lactobacillus
D. Nitrosomonas

Correct Answer: Option A


Explanation:
Rhizobium species form symbiotic root nodules in legumes and fix atmospheric nitrogen into ammonia. Azotobacter is free-living, Nitrosomonas nitrifies, Lactobacillus ferments.

This question belongs to: Science Biology
Question #3
Charles Darwin proposed the theory of natural selection based on observations during his voyage on:
A. HMS Endeavour
B. HMS Victory
C. HMS Beagle
D. HMS Challenger

Correct Answer: Option C


Explanation:
Darwin traveled as a naturalist on the HMS Beagle (1831-1836) and made extensive observations, especially in the Galápagos Islands. His observations of finches' beak adaptations led to the concept of natural selection as the mechanism for evolution. 'On the Origin of Species' (1859) laid out his theory. HMS Challenger was an oceanographic expedition. HMS Endeavour was Captain Cook's ship.

This question belongs to: Science Biology