A DNA segment has a total of 2,000 nucleotides, out of which 520 are adenine containing nucleotides. How many purine bases this DNA segment possesses ?

Advertisement Remove all ads

#### Solution

Adenosine (A) and guanine (G) are purines, while thymine (T) and cytosine (C) are pyrimidines. According to the Chargaff's rule, purine will pair with pyrimidines; therefore, 'A pairs with T' and 'C pairs with G'.

We have 520 adenine bases; therefore, there should be 520 thymine bases.

A + T = 520 + 520 = 1040

Total number of nucleotides are 2000.

∴ G + C = 2000 − 1040 = 960

G = 960/2 = 480

Therefore, total number of purine bases are 1000 (A + G = 520 + 480).

Concept: Structure of DNA and RNA

Is there an error in this question or solution?

#### APPEARS IN

Advertisement Remove all ads