DNA Replication Lecture Notes

These flashcards cover key concepts related to DNA replication, including structures, enzymes, and processes.

DNA nucleotide

A building block of DNA, consisting of a phosphate group, a sugar, and a nitrogenous base.

Purine

A type of nitrogenous base in DNA, includes Adenine (A) and Guanine (G).

Pyrimidine

A type of nitrogenous base in DNA, includes Thymine (T) and Cytosine (C).

Antiparallel strands

Refers to the orientation of the two DNA strands running in opposite directions, one from 5' to 3' and the other from 3' to 5'.

DNA replication

The process of making an exact copy of DNA.

Sister chromatids

Identical copies of a chromosome connected by a centromere.

Origins of replication

Specific sites where DNA strands are separated to begin replication.

Topoisomerase

An enzyme that relieves the twisting strain of the double helix during DNA replication.

Helicase

An enzyme that separates double-stranded DNA into single strands.

Primase

An enzyme that synthesizes a short RNA primer used by DNA polymerase to initiate nucleotide strand synthesis.

DNA polymerase III

An enzyme responsible for adding dNTPs to the growing DNA strand during replication.

Lagging strand

The strand of DNA that is synthesized discontinuously in short segments (Okazaki fragments).

Leading strand

The strand of DNA that is synthesized continuously in the 5' to 3' direction.

Okazaki fragments

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

DNA ligase

An enzyme that joins Okazaki fragments together and seals breaks in the sugar-phosphate backbone.

Telomeres

Repeating sequences at the ends of eukaryotic chromosomes that protect genes from being eroded during replication.

Telomerase

An enzyme that extends telomeres and maintains chromosome length.

Nuclease

An enzyme that cuts DNA strands at specific points to remove damaged sections of DNA.

Nucleotide excision repair

A DNA repair mechanism that removes damaged nucleotides and replaces them with the correct ones.

Semiconservative replication

A method of DNA replication where each new DNA molecule contains one original strand and one newly synthesized strand.

DNA backbone

The structural framework of DNA, formed by sugar and phosphate groups.