11/6 NOTES- DNA REPLICATION

Mitosis

The process by which a cell divides its nucleus and contents, leading to the formation of two daughter cells.

Chromatin

The complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells.

Nucleosome

A structural unit of chromatin consisting of a segment of DNA wound around a core of histone proteins.

DNA Polymerase

An enzyme responsible for synthesizing DNA molecules from nucleotides, the building blocks of DNA.

Semi-conservative replication

The process of DNA replication in which each of the two resulting DNA molecules has one old strand and one new strand.

Origin of replication

The specific location on a chromosome where DNA replication begins, characterized by rich sequences of adenine (A) and thymine (T) bases.

Helicase

An enzyme that unwinds the DNA double helix at the replication fork, separating the two strands of DNA.

Okazaki fragments

Short sequences of DNA nucleotides synthesized discontinuously on the lagging strand during DNA replication.

Primase

An RNA polymerase enzyme that synthesizes a short RNA primer to initiate DNA replication.

DNA Ligase

An enzyme that joins Okazaki fragments together by forming phosphodiester bonds between the fragments.

Single-Stranded Binding Proteins (SSBPs)

Proteins that bind to and stabilize single-stranded DNA during replication, preventing it from re-annealing.

5' to 3' direction

The direction in which DNA polymerases synthesize new DNA strands by adding nucleotides; critical for DNA replication.

Heterochromatin

Regions of chromatin that are tightly packed and not actively transcribed.

Leading strand

The continuous strand of DNA synthesized in the same direction as the replication fork opens.

Lagging strand

The discontinuously synthesized strand of DNA made in short fragments in the opposite direction of the replication fork.

Base pairing rules

Rules that dictate the pairing of nitrogenous bases in DNA, where adenine pairs with thymine and guanine pairs with cytosine.

Transcription

The process of copying a segment of DNA into RNA by the enzyme RNA polymerase.

Nucleotide

The basic building block of DNA and RNA, consisting of a sugar, a phosphate group, and a nitrogenous base.