Question

If there are 10,000 nitrogenous base pairs in a DNA then how many nucleotides are there?

• A. 500
• B. 10,000
• C. 20,000
• D. 40,000

Answer 1

Answer: (C)

20,000

Base pair means two complementary nucleotides one of which is purine (Adenine or Guanine) and the other is pyrimidine (Thymine or Cytosine). Adenine always pairs with Thymine or vice versa and Guanine always pairs with Cytosine or vice versa.

Hence 1 base pair has 2 nucleotides, so 10,000 nitrogenous bases will have 10,000 x 2 = 20,000 nucleotides.

So, the correct answer is '20,000'.