Question

Which of the following is correct regarding HIV?

I.HIV is a retrovirus with double stranded RNA.
II.HIV is a retrovirus that contains single stranded RNA.
III.HIV is a non-enveloped retrovirus with double stranded stranded RNA molecules.
IV.HIV causes severe immunodeficiency in the due course of its infection.

• A.
  I and III only
  
• B. II and IV only
• C. I, II and III
• D. II, III and IV

Answer 1

The correct option is B II and IV only

HIV, Human Immunodeficiency Virus is the causative agent of Acquired Immunodeficiency Syndrome (AIDS). HIV attacks and weakens the immune system of the patient and thus makes him/her vulnerable to opportunistic infections.
HIV is a spherical enveloped virus. The outermost layer is an envelope made up of a lipid bilayer which consists of a large number of knob-like spikes made up of viral glycoproteins (gp). The envelope is derived from the host cell membrane and encloses a double layer of protein coat. Interior to the protein coat lies the genetic material which is in the form of 2 identical copies of ssRNA and is associated with 2 molecules of an enzyme called reverse transcriptase.
The initial hosts of HIV in the body are the macrophages within which the viral reverse transcriptase enzyme catalyses the conversion of the 2 strands of viral genomic RNA into a double stranded DNA. The viral DNA integrates itself into the host genome and directs the macrophages and helper T cells to synthesise viral particles.
As the number of helper T cells in the body progressively reduces, the severe immunodeficiency ensues and growth of opportunistic pathogens (organisms which can cause disease only when immunity is low) is favoured.
Thus, only statements II and IV are correct.