Which statement is true?

Options

A. adenine has 4 nitrogen atoms
B. cytosine has 3 nitrogen atoms
C. guanosine has 3 nitrogen atoms
D. uracil has 5 nitrogen atoms

Answer

A

Explanation

Nitrogen containing organic ring compounds are present in the nucleotides of nucleic acid. They are of two types two ringed nitrogenous compound eg., adenine and guanine. Purines are 9-membered double rings and each has four N-atoms at `1',3',7'` and `9'` positions. Pyrimidines are single ringed nitrogenous compounds e.g., cytosine and thymine. A pyrimidine has two N-atoms at 1' and 3' positions.