Which of the following does not hold true for retroviruses.a)They replicate through a DNA intermediateb)Their genome is ds DNAc)They show a property of reverse transcriptiond)Their hosts are mostly animal cellsCorrect answer is option 'B'. Can you explain this answer?

Question

Answer

Retroviruses are a family of RNA viruses that have the ability to reverse transcribe their RNA genome into DNA. However, one of the statements provided in the options is incorrect. Let's break down each option to understand why option B is the correct answer.

a) They replicate through a DNA intermediate:
Retroviruses do indeed replicate through a DNA intermediate. This process involves the conversion of their RNA genome into DNA by the enzyme reverse transcriptase. The DNA is then integrated into the host cell's genome, where it can be transcribed and translated to produce viral proteins.

b) Their genome is ds DNA:
This statement is incorrect. Retroviruses have a single-stranded RNA genome, not double-stranded DNA. The RNA genome serves as a template for the synthesis of DNA during reverse transcription.

c) They show a property of reverse transcription:
This statement is accurate. Retroviruses are unique in that they are able to reverse transcribe their RNA genome into DNA. This process is catalyzed by the enzyme reverse transcriptase, which is carried by the virus. Reverse transcription allows the virus to integrate its genetic material into the host cell's genome.

d) Their hosts are mostly animal cells:
This statement is true. Retroviruses primarily infect animal cells, although some exceptions exist. For example, the human immunodeficiency virus (HIV) is a retrovirus that specifically infects human immune cells.

In conclusion, option B is the correct answer because retroviruses have a single-stranded RNA genome, not a double-stranded DNA genome. Retroviruses are known for their ability to reverse transcribe their RNA genome into DNA, and they primarily infect animal cells.

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