Question

In which forms do nitrogenous bases occur?

Answer 1

Nitrogenous bases:

1. A nitrogenous base is a nitrogen-containing organic molecule having similar physical properties as a base.
2. They occur in two different forms.

Purines:

1. They are double-ringed structures.
2. They are larger than pyrimidines.
3. Two purines are adenine and guanine.
4. These are present in both DNA and RNA.

Pyrimidines:

1. They are single-ringed structures.
2. They are smaller than purines.
3. Three pyrimidines are cytosine, uracil, and thymine.
4. Uracil is only found in RNA.
5. Cytosine is common in both RNA and DNA.
6. Thymine is only present in DNA.