Question

If a sample of DNA if adenine is 28% what will be the amount of Cytosine present

• A. 23%
• B. 25%
• C. 46%
• D. 22%

Answer 1

The Correct Option is D

In a DNA molecule, the base pairing rule states that adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). According to Chargaff's rules, the amount of adenine will equal the amount of thymine, and the amount of cytosine will equal the amount of guanine in a DNA molecule. Given that adenine is 28%, thymine will also be 28%.

Thus, the combined percentage of adenine and thymine is:

A + T = 28% + 28% = 56%

This leaves the remaining 44% for cytosine and guanine. Since cytosine and guanine are always equal, we have:

C + G = 44%

C = G = 44% / 2 = 22%

Therefore, the amount of cytosine present is 22%.