Arrange the steps involved in retroviral infection of an animal cell in a sequential order:
(A) More virus particles are made.
(B) Virus eventually enters T-lymphocytes.
(C) Viral DNA incorporated in host DNA.
(D) RNA of HIV enters macrophages.
(E) By reverse transcription viral RNA forms viral DNA.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (D), (E), (C), (A), (B)
HIV RNA first enters macrophages (D); reverse transcription forms viral DNA (E); the DNA joins the host DNA (C); the cell makes more virus particles (A); the virus then enters helper T-lymphocytes (B).
NCERT Extract:
AIDS – “… After getting into the body of the person, the virus enters into macrophages where RNA genome of the virus replicates to form viral DNA with the help of the enzyme reverse transcriptase. This viral DNA gets incorporated into host cell’s DNA and directs the infected cells to produce virus particles (Figure 7.6). The macrophages continue to produce virus and in this way acts like a HIV factory. Simultaneously, HIV enters into helper T-lymphocytes (TH), replicates and produce progeny viruses.”