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? 

(a) 1 Only 

(b) 2 Only 

(c) Both 1 and 2 

(d) Neither 1 nor 2 

Ans: b 

Explanation:

Adenovirus

Adenoviruses are non-enveloped, double-stranded DNA viruses. People with weakened immune systems are at high risk for developing severe illness caused by adenovirus infection. 

Adenoviruses most commonly cause respiratory illness. The illnesses can range from the common cold to pneumonia, croup, and bronchitis. Depending on the type, adenoviruses can cause other illnesses such as gastroenteritis, conjunctivitis, cystitis, and, less commonly, neurological disease.

Retrovirus

Retroviruses are linear single stranded RNA viruses with a lipid containing glycoprotein viral envelope. After infecting a cell, a retrovirus uses an enzyme called reverse transcriptase to convert its RNA into DNA. The retrovirus then integrates its viral DNA into the DNA of the host cell, which allows the retrovirus to replicate. HIV, the virus that causes AIDS, is a retrovirus.

Hence, statement 1 is incorrect & statement 2 is correct.

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