Question

UPSC Prelims 2021 Question:

Consider the following statements:

  1. Adenoviruses have single stranded DNA genomes whereas retroviruses have double-stranded DNA genomes. 
  2. Common cold is sometimes caused by an adenovirus whereas AIDS is caused by a retrovirus.

Which of the statements given above is/are correct?

  1. 1. 1 only
  2. 2. 2 only
  3. 3. Both 1 and 2
  4. 4. Neither 1 nor 2

Answer (Detailed Solution Below)

Option 2: 2 only

Detailed Solution

Explanation: 

  • Viruses come in many shapes and sizes, and only replicate when inside living cells. Most viruses contain 2 or 3 major parts: genetic information made up of RNA or DNA, a molecule chain to carry these genetic materials, and a protein coat to act as protection.

  • The key difference between Adenovirus and Retrovirus is as follow:

Adenovirus

Retrovirus

This virus contains a double-stranded DNA.

It is considered as a single stranded RNA virus. Retroviruses store their genetic information using RNA instead of DNA. So, statement 1 is not correct.

An adenovirus is a non-enveloped virus, (meaning it has no protective protein coating). So, the genetic information is not stored inside the virus.

A retrovirus is an example of an enveloped virus, making it more resilient and causing a higher tendency of infection or diseases.

Adenoviruses are common viruses that typically cause mild cold- or flu-like illness. Adenoviruses can cause illness in people of all ages any time of year.

In humans, a retrovirus known as human T-cell lymphotropic virus type 1 (HTLV-1) causes a form of cancer called adult T-cell leukemia (ATL). The retrovirus known as human immunodeficiency virus (HIV) causes AIDS in humans. So, statement 2 is correct.

Therefore, option (2) is the correct answer.

Subject: Science & Technology | Health

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