Question

What is the constant ratio for dna ?

a. a+g/t+c

b. a+t/g+c

c.a+c/u+g

d.a+u/c+g?

Answer 1

yes the correct option is b

Answer 2

Constant ratio for DNA is a) a+g/t+c.

Chargaff’s rule states that for any DNA, the ratio of purine and pyrimidine bases are present at a constant ratio of 1 : 1. Adenine(A) and guanine(G) are purines and thymine (T) and cytosine (C) are pyrimidines.

Purines always pair with pyrimidines in the DNA. Hence, the number of purines is always equal to the number of pyrimidines present at any given time. Therefore, the ratio of total number of purines to pyrimidines is a constant ratio for DNA.