DNA Replication and Recombination

These flashcards cover key concepts from the lecture on DNA replication and recombination, including definitions, significant experiments, and the functions of various enzymes involved.

What type of replication does DNA undergo according to the semiconservative model?

Each replicated DNA molecule consists of one old strand and one new strand.

What is the role of DNA polymerases during DNA synthesis in bacteria?

DNA polymerases are enzymes that facilitate the synthesis of DNA by adding nucleotides to a growing strand.

What experiment did Meselson and Stahl conduct to demonstrate semiconservative replication?

They labeled E. coli DNA with 15N and observed the incorporation of 14N, showing that each new DNA molecule contained one old and one new strand.

What is the function of the origin of replication (ORI)?

It is the site where DNA replication begins, and is characterized by the unwinding of the DNA helix to form replication forks.

How many polymerases are involved in bacterial DNA synthesis?

There are five DNA polymerases involved: DNA polymerase I, II, III, IV, and V.

What are the three modes of DNA replication?

Semiconservative, conservative, and dispersive.

What does the term 'replicon' refer to in DNA replication?

The length of DNA that is replicated in one initiation event.

What was the significance of the Taylor–Woods–Hughes experiment?

It demonstrated that DNA replication is semiconservative in eukaryotes using Vicia faba.

What 5' to 3' direction synthesis in DNA polymerase I enables?

Chain elongation by adding nucleotides to the growing 3' end of the DNA strand.

Which DNA polymerase is responsible for excising primers during DNA synthesis?

DNA polymerase I.

What is the main activity of DNA polymerases I, II, and III regarding existing DNA strands?

They can elongate existing DNA strands (primers) but cannot initiate DNA synthesis.

What role do DNA polymerases IV and V play?

They are involved in DNA repair processes.

What is the gene product of the polA gene?

DNA polymerase I.

The polB gene encodes for which enzyme involved in bacterial DNA replication?

DNA polymerase II.

Which genes contribute to forming the subunits of DNA polymerase III?

dnaE, N, Q, X, Z.

What is the product of the dnaG gene?

Primase.

Which E. coli genes are associated with the initiation of DNA replication?

dnaA, I, P.

What is the role of the dnaB and dnaC gene products?

Helicase at oriC.

The gyrA and gyrB genes encode for subunits of which enzyme?

Gyrase.

What is the gene product of lig?

DNA ligase.

Which gene encodes for DNA helicase in E. coli?

rep.

What do the ssb genes produce?

Single-stranded binding proteins.

The rpoB gene encodes for which component?

RNA polymerase subunit.