1. Deoxyribose sugar: This is a five-carbon sugar that forms the backbone of the DNA molecule.

2. Phosphate group: This is a negatively charged group that attaches to the deoxyribose sugar.

3. Nitrogenous base: This is a molecule containing nitrogen that attaches to the deoxyribose sugar. There are four different nitrogenous bases in DNA:

* Adenine (A)

* Guanine (G)

* Cytosine (C)

* Thymine (T)

The Structure of a DNA Nucleotide

The phosphate group is attached to the 5' carbon of the deoxyribose sugar, and the nitrogenous base is attached to the 1' carbon. The 3' carbon of the deoxyribose sugar is where the next nucleotide in the chain will attach, forming a phosphodiester bond.

Base Pairing

The nitrogenous bases in DNA pair up in a specific way:

* Adenine (A) always pairs with Thymine (T)

* Guanine (G) always pairs with Cytosine (C)

This complementary base pairing is essential for the structure and function of DNA.

Key Functions

The sequence of nucleotides in DNA determines the genetic code, which dictates the amino acid sequence of proteins. Proteins are responsible for many important functions in the body, so DNA plays a crucial role in controlling these functions.