replikáciu

Replikácia is a fundamental biological process that involves the duplication of deoxyribonucleic acid (DNA). This process is essential for cell division and heredity, ensuring that genetic information is accurately passed from one generation of cells to the next. Replikácia occurs in three main stages: initiation, elongation, and termination.

Initiation begins when an enzyme called helicase unwinds the DNA double helix, separating the two strands. Each separated strand then serves as a template for the synthesis of a new complementary strand. Proteins called single-strand binding proteins bind to the separated strands to prevent them from re-annealing.

Elongation is the phase where new DNA strands are synthesized. The enzyme DNA polymerase adds nucleotides to the growing strand, following the base-pairing rules (adenine with thymine, and guanine with cytosine). DNA polymerase can only add nucleotides in a 5' to 3' direction, leading to the synthesis of one strand (the leading strand) continuously and the other strand (the lagging strand) discontinuously in short fragments called Okazaki fragments. Enzymes like primase create RNA primers to initiate DNA synthesis on the lagging strand. Ligase then joins these Okazaki fragments together.

Termination occurs when the entire DNA molecule has been replicated. Specific termination sequences in the DNA signal the end of replication. The result of this process is two identical DNA double helices, each consisting of one original strand and one newly synthesized strand. This semiconservative replication ensures genetic fidelity.