what is meant by purine and pyrimidine?

 

Dear Student, Monu

Purine and Pyrimidine both are nitrogenous bases. Purines consists of adenine and guanine whereas pyrimidine consists of cytosine, uracil and thymine. These nitrogenous bases together  with pentose sugar and phosphate group forms the structure of a polynucleotide.

Hope this answer will help you.

Cheers !