DNA Replication, Repair & Recombination L3 part 2

These flashcards cover key terms and concepts related to DNA replication, repair, and recombination, providing definitions and descriptions for each term.

Semi-conservative replication

A type of DNA replication where each new DNA molecule consists of one old strand and one newly synthesized strand.

DNA polymerase

An enzyme that synthesizes new DNA strands by adding nucleotides to an existing chain.

Proofreading mechanism

The process by which DNA polymerase checks and corrects errors in newly synthesized DNA.

Okazaki fragments

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

DNA ligase

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

Homologous recombination

A process that allows for exchange of genetic material between homologous DNA molecules.

Holliday Junction

A key intermediate structure formed during homologous recombination, characterized by crossing over of DNA strands.

Base excision repair (BER)

A DNA repair process that removes and replaces damaged or incorrect bases in the DNA.

Telomeres

The protective caps located at the ends of eukaryotic chromosomes that safeguard genetic data.

Nucleotide excision repair (NER)

A DNA repair mechanism that removes a stretch of DNA containing damaged bases.

Transversion mutation

A type of point mutation that involves the substitution of a purine for a pyrimidine or vice versa.

Deamination

The removal of an amino group from a base, leading to potential mutations.

NHEJ (Non-Homologous End Joining)

A repair mechanism for double-strand breaks in DNA that does not require a homologous template.

Methylation

The addition of methyl groups to DNA, which can influence gene expression and initiate DNA replication.

SSB proteins

Single-strand binding proteins that stabilize unwound DNA during replication.

Topoisomerase

An enzyme that modifies the supercoiling of DNA, relieving torsional strain ahead of the replication fork.

Chiasma

The point at which sister chromatids exchange genetic material during homologous recombination.

Mutation rate

The frequency at which changes in the DNA sequence occur in a given organism.

MutS and MutL

Proteins involved in the recognition and repair of mismatched DNA bases.

Adenine and Guanine

Purine bases that are part of DNA structure, with A binding to T and G binding to C.

Guanine and Cytosine

Pyrimidine bases that are part of DNA structure, with G binding to C.

Radiation-induced mutations

Genetic changes caused by exposure to forms of radiation that damage DNA.