IMAT 2017 Q24 [Human Immunodeficiency Virus]

Past Papers Solutions Archives
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1

Which of the following components of a human immunodeficiency virus (HIV) contain peptide bonds?

  1. capsid
  2. envelope
  3. reverse transcriptase

A. 2 and 3 only
B. 1 and 2 only
C. 1, 2 and 3
D. 3 only
E. 1 and 3 only

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2

The correct answer is C.

First things first, what is a peptide bond ?

  • It is a covalent chemical bond that is found between 2 successive amino-acids ; it is formed between the carboxyl and amino group of 2 distinct molecules.
  • They allow the formation of long amino acids, and therefore, of proteins.

Now, let’s review each component one by one :

  1. The capsid is the structure that contains the genetic material of the virus, either DNA or RNA. It is made of several protein units, and therefore contains peptide bonds. In consequence, this item is correct.

  2. The enveloppe is an external structure that exists in some viruses : it contains the capsid. It has a role in the process of viral infection, and to protect the virus against the immune system. It is made of a lipidic membrane and glycoproteins. This item is therefore correct.

  3. Reverse transcriptase, like any other molecule that ends with “-ase”, is an enzyme and is therefore a protein. Its role is to produce a complementary DNA strand from a RNA template. This item is also correct.

Considering the fact that all of these items are correct, the right answer is C.

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