The nucleic acid from various viruses was extracted and the

The nucleic acid from various viruses was extracted and the base compositions determined. What is the nature of the nucleic acid in each virus? Explain your reasoning. Virus 1) 35% A, 35% T, 15% G, 15%C Virus 2) 35% A, 15% T, 25% G, 25% C Virus 3) 35% A, 30% U, 30% G. 5% C Virus 4) 20% A, 20% U, 30% G, 30% C

Solution

Virus 1 is a double stranded DNA virus because the percentage of A is equal to T and the percentage of G is equal to Cytosine. In double stranded DNA A=T and G=C as A pairs with T and G pairs with C

Virus 2 is single stranded DNA virus as the percentage of A is not equal to T. In ssDNA no helical base pairing occurs.

Virus 3 is single stranded RNA virus as it has Urasil in place of Thymine. Urasil is present in RNA in place of thymine in DNA. It has different percentages of all nucleotides hence it its single stranded

Virus 4 is double stranded RNA virus as it has Urasil in place of Thymine. Urasil is present in RNA in place of thymine in DNA. In this the percentage of A is equal to Urasil and the percentage of G is equal to C