Nucleotide Structure and Components

Nucleotide

• Basic building block of nucleic acids (DNA and RNA).
• Composed of three components: 5 carbon sugar, nitrogenous base, and phosphate group.

5 Carbon Sugar

• Essential part of a nucleotide.
• Types: Ribose (in RNA) and Deoxyribose (in DNA).

Ribose

• A five-carbon sugar specifically found in RNA.
• Key component that helps form RNA structure.

Deoxyribose

• A five-carbon sugar in DNA nucleotides.
• Lacks one oxygen atom compared to ribose.

Nitrogenous Bases

• Organic molecules containing nitrogen, crucial for nucleotide structure.
• Types include Adenine, Guanine, Cytosine, Thymine (DNA), and Uracil (RNA).

Purines

• Nitrogenous bases with a double-ring structure.
• Includes Adenine (A) and Guanine (G).

Adenine (A)

• A purine that pairs with Thymine in DNA and Uracil in RNA.

Guanine (G)

• A purine that pairs with Cytosine in both DNA and RNA.

Pyrimidines

• Nitrogenous bases characterized by a single-ring structure.
• Comprise Cytosine, Thymine, and Uracil.

Cytosine (C)

• A pyrimidine paired with Guanine in both DNA and RNA.

Uracil (U)

• A unique pyrimidine found only in RNA.
• Pairs with Adenine in RNA.

Thymine (T)

• A pyrimidine exclusive to DNA.
• Pairs with Adenine in DNA.

Nucleoside

• Combination of a nitrogenous base and a sugar (ribose or deoxyribose) without a phosphate group.

Base Pairing Rules

• Specific pairing rules dictate nucleobase interactions:
  • In DNA: Adenine pairs with Thymine; Cytosine pairs with Guanine.
  • In RNA: Adenine pairs with Uracil; Cytosine pairs with Guanine.

Pentose Sugar

• Another term for the five-carbon sugar found in DNA and RNA nucleotides.

Phosphate Group

• Attached to the fifth carbon of either ribose or deoxyribose, contributing to nucleotide structure.

Nitrogenous Base

• Attached to the first carbon of ribose or deoxyribose, crucial for forming the genetic structure of DNA and RNA.