DNA is made up of four nucleotide bases: adenine (A), cytosine (C), guanine (G), and thymine (T). These bases pair up in a specific way: A always pairs with T, and C always pairs with G. This base pairing is crucial as it allows the two strands of DNA to form a stable structure.

The sequence of these bases along a DNA molecule is what determines the genetic information encoded in the DNA. Genes, which are specific regions of DNA, are responsible for coding proteins that perform various functions in the body.

DNA replication is the process by which a cell duplicates its DNA prior to cell division. It is a complex process involving multiple enzymes and proteins that ensure the accurate duplication of the genetic information. During replication, the double helix unwinds and the two strands separate, serving as templates for the synthesis of two new complementary strands. Each daughter DNA molecule contains one original strand and one newly synthesized strand, a process known as semi-conservative replication.

DNA is also subject to mutations, which are changes or errors in the DNA sequence. Mutations can occur due to various factors, such as exposure to certain chemicals, radiation, or errors during DNA replication. Some mutations can have no effect, while others can lead to genetic disorders or diseases.

Overall, DNA is a fundamental molecule that carries the genetic information necessary for life and plays a crucial role in various biological processes.