Nitrogenous bases

Definition

Nitrogenous bases are organic molecules that contain nitrogen and act as the fundamental building blocks of nucleic acids like DNA and RNA. They pair with each other to form the rungs of the DNA double helix, enabling genetic information storage and transfer.

5 Must Know Facts For Your Next Test

1. There are five primary nitrogenous bases: adenine (A), thymine (T), cytosine (C), guanine (G), and uracil (U).
2. In DNA, adenine pairs with thymine, and cytosine pairs with guanine through hydrogen bonds.
3. Uracil replaces thymine in RNA, pairing with adenine instead.
4. Nitrogenous bases are classified into two categories: purines (adenine and guanine) and pyrimidines (cytosine, thymine, and uracil).
5. The sequence of nitrogenous bases in DNA determines an organism's genetic code.

Review Questions

• What are the base pairing rules for DNA?
• Which nitrogenous base is found in RNA but not in DNA?
• How are purines different from pyrimidines?

Related terms

DNA: Deoxyribonucleic acid, a molecule that carries genetic instructions in living organisms.

RNA: Ribonucleic acid, a nucleic acid involved in protein synthesis and gene regulation.

Nucleotide: The basic structural unit of nucleic acids like DNA and RNA, consisting of a nitrogenous base, a sugar molecule, and a phosphate group.