At the most basic level, DNA is composed of a sequence of smaller molecules called nucleotides.
These nucleotides are the fundamental building blocks of the DNA molecule. Each nucleotide consists of three components:
- A sugar molecule: This is deoxyribose, a five-carbon sugar.
- A phosphate group: This provides the "backbone" structure for the DNA strand.
- A nitrogenous base: These are the informational units and come in four types: adenine (A), guanine (G), cytosine (C), and thymine (T).
The sequence of these nitrogenous bases along the DNA strand is what encodes the genetic information. The bases pair up in a specific way: adenine (A) always pairs with thymine (T), and guanine (G) always pairs with cytosine (C). This complementary base pairing is crucial for DNA replication and protein synthesis. The two strands of DNA wind around each other to form the familiar double helix structure.
Therefore, while the double helix is the iconic visual representation of DNA, and genes are functional units, the nucleotide is the most basic molecular component.
