Question

If a species contains 40% guanine in its DNA, what is the percentage of cytosine that is would contain?

• A. 60
• B. 40
• C. 27
• D. 30

Answer 1

Answer: (B)

40

Each nucleotide base of DNA is paired with another base with the help of hydrogen bond. There are two types of bases, purine (Adenine, guanine) and pyrimidine (thymine, cytosine) and they are paired always against each other. Hence adenine is always paired with thymine while guanine is paired with cytosine. Hence, if a DNA contains 40% guanine, it will contain an equal percentage of cytosine.

So, the correct option is '40'.