Chapter 12: DNA Replication and Recombination

These flashcards cover key concepts and details related to DNA replication and recombination as described in Chapter 12 of the lecture notes.

What is the main conclusion of the Meselson-Stahl experiment regarding DNA replication?

DNA replication is semiconservative.

What are the three models originally proposed for DNA replication?

Conservative, Dispersive, Semiconservative.

What is theta replication?

A common form of replicating circular DNA in which DNA strands separate at the origin, forming a replication bubble with one or two replication forks.

What is the issue with replicating linear chromosomes that eukaryotes face?

The end replication problem, which can lead to chromosomal shortening.

What role do Okazaki fragments play in DNA replication?

They are short DNA fragments synthesized on the lagging strand that are later fused to form a continuous DNA strand.

What is the function of helicase in DNA replication?

Helicase unwinds the DNA strands at the replication fork.

What is the role of DNA polymerase I?

It removes RNA primers and replaces them with DNA during lagging strand synthesis.

What is branch migration in homologous recombination?

The process where the two nucleotide strands exchange positions, creating heteroduplex DNA.

What is the main difference between theta and rolling-circle replication?

Theta replication involves circular DNA without strand breakage, while rolling-circle replication requires a break in one of the nucleotide strands.

What enzyme is responsible for resolving Holliday junctions during homologous recombination?

RuvC cleaves the Holliday junctions to separate the strands.