DNAreplikaatioksi

DNA replication is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules. This process is essential for cell division and growth, as well as for the transmission of genetic information from one generation to the next. DNA replication occurs in the S phase of the cell cycle and is initiated at specific sites called origins of replication.

The replication process begins with the unwinding of the DNA double helix by an enzyme called helicase. This creates a replication fork, where the two strands of the DNA molecule are separated. The separated strands then serve as templates for the synthesis of new complementary strands. This synthesis is catalyzed by the enzyme DNA polymerase, which adds nucleotides to the 3' end of the growing strand in the 5' to 3' direction.

DNA replication is semi-conservative, meaning that each new DNA molecule consists of one original strand and one newly synthesized strand. This results in two daughter molecules that are identical to the original molecule. The process is also bidirectional, meaning that replication occurs simultaneously in both directions from the origin of replication.

Errors in DNA replication can occur due to various factors, such as mutations in the DNA polymerase enzyme or environmental factors. These errors can lead to genetic mutations, which can have significant effects on an organism's phenotype and health. To ensure the fidelity of DNA replication, cells have developed several mechanisms to proofread and correct errors, such as the use of DNA repair enzymes and the removal of damaged DNA by nucleases.