Question

A nitrogen base is linked to sugar by a glycosidic bond at carbon number

• A. $1^{{}^{\prime }}$
• B. $2^{{}^{\prime }}$
• C. $4^{{}^{\prime }}$
• D. $5^{{}^{\prime }}$

Answer 1

The correct option is A $1^{{}^{\prime }}$

DNA has nitrogenous base, phosphate and sugar. The nitrogenous bases present in the DNA are purines and pyrimidines. Purines are double ring while pyrimidines are single ring structure. Adenine and guanine are purines while thymine and cytosine are pyrimidines. A purine is attached to pyrimidine by hydrogen bond. Adenine is attached to thymine by two hydrogen bonds while three hydrogen bond is present between guanine and cytosine. The sugar is linked to nitrogenous base at the first carbon by glycosidic bond.

So, the correct answer is option A.