Telomerase synthesizes DNA in the _____ direction.

Telomerase is an enzyme that adds repetitive nucleotide sequences to the ends of chromosomes, known as telomeres. This process helps prevent the loss of important DNA sequences during cell division, thereby maintaining chromosome integrity and stability. Telomerase is particularly active in stem cells and cancer cells, where it supports continuous cell division.

DNA synthesis occurs in the 5' to 3' direction, meaning that new nucleotides are added to the 3' end of the growing DNA strand. This directionality is due to the enzymatic mechanism of DNA polymerases, which require a free 3' hydroxyl group to add new nucleotides. Telomerase, like other DNA polymerases, follows this 5' to 3' synthesis rule.

Telomeres are repetitive nucleotide sequences at the ends of linear chromosomes, protecting them from degradation and fusion with neighboring chromosomes. In humans, the sequence is typically TTAGGG, repeated thousands of times. Telomeres shorten with each cell division, and telomerase helps counteract this shortening in certain cell types, contributing to cellular longevity.