Question

Read the sources given and answer any four from the questions given below:

Acquired immune deficiency syndrome (AIDS) is an immunodeficiency disease caused by a retrovirus called human immunodeficiency virus (HIV). This retrovirus has RNA as its hereditary material which can replicate via DNA copies. These viruses have an amazing ability of making RNA copies of themselves which can then be recopied to make double-stranded DNA (RNADNA) and these DNA copies can be integrated randomly into one of the chromosomes of the host DNA.This is possible because they carry the gene for reverse transcription. The copying of RNA to DNA is done by enzyme RNAdependent DNA polymerase or reverse transcriptase. HIV selectively infects and kills T-helper cells. Depletion of T-helper cells weaken the acquired protective immune response of the body. HIV is a retrovirus that utilises reverse transcriptase to produce cDNA (DNA copy of RNA genes). сDNA integrates into the cell's chromosomes before it reproduces and makes copies of itself.

1. Which of the following statement is applicable to a retrovirus?\
   1. has DNA as hereditary material
   2. can form RNA from DNA
   3. can form DNA from RNA
   4. both (a) and (b)
2. The type of cells that AIDS virus destroys in the body are
   1. B lymphocytes
   2. thrombocytes
   3. T-helper cells
   4. both (b) and (c)
3. RNA-dependent DNA polymerase can
   1. destroy immune system
   2. form cDNA
   3. copy host DNA
   4. integrate RNA to host DNA
4. Which of the following is true for HIV?
   1. It can carry reverse transcription
   2. It destroys the immune system of body
   3. both (a) and (b)
   4. it causes cancer in the body
5. The following type of DNA is called the cDNA
   1. DNA copy of viral RNA
   2. host DNA
   3. copy of host DNA
   4. both (b) and (c)

Answer 1

1. can form DNA from RNA
2. T-helper cells
3. form cDNA
4. both (a) and (b)
5. both (b) and (c)