Question

A DNA molecule is 160 base pairs long. It has 30% Guanine. How many Adenine bases are present in this DNA molecule?

Options

• 48

• 64

• 96

• 192

Answer 1

64

Explanation:

In a DNA molecule, Guanine (G) pairs with Cytosine (C), and Adenine (A) pairs with Thymine (T). The percentage of G equals the percentage of C.

If 30% of the bases are Guanine, 30% must also be Cytosine. This leaves 40% for Adenine and Thymine combined. Since Adenine pairs with Thymine in equal amounts, half of 40% will be Adenine.

Percentage of Adenine

`= 40/2`

= 20%

Now, to find the number of Adenine bases in a 160 base pair molecule:

Number of Adenine bases

= 20% × 160

= 32 Adenine bases.

Therefore, the number of Adenine bases in this DNA molecule is 64