BIO282 Block 1 DNA Cloning and Recombination

Which enzyme is responsible for unwinding DNA double helix at the replication fork?

Helicase

What is the primary function of primase in DNA replication?

Synthesis RNA primer

DNA polymerase can add nucleotides to which end of growing strand?

3’ end

In prokaryotic cells, which enzyme removes RNA primers and replaces them with DNA?

DNA Polymerase I

Okazaki fragments are formed on which strand during DNA replication?

Lagging strand

Which enzyme joins okazaki fragments together?

DNA ligase

What is the function of DNA gyrase in bacterial DNA replication?

Relieves supercoiling ahead of replication fork

Which enzyme is responsible for proof reading and correcting errors during DNA replication?

DNA Polymerase III

What is the function of RecA in E.coli?

Strand Invasion

What is the function of RecBCD in E.coli?

Generates nicks and unwinds DNA

What is the function of RuvAB in E.coli?

Branch Invasion

What is the function of RuvC in E.coli?

Cleavage of holliday junctions

What is the function of SSB in E.coli?

Stabilising single stranded DNA

What is the function of DNA Ligase in E.coli?

Seals nicks

Primary difference between HR and NHEJ

HR requires a homologous DNA template

Which protein complex recognises the double strand break during NHEJ

Ku70/Ku80

Why is NHEJ considered error prone?

Randomly inserts and deletes bases?

How to Trypanosomes evade immune detection in humans?

Switching their expressed surface glycoprotein genes using HR.

What is template switching in the context of antigenic variation?

Replacing expressed VSG gene with a silent one via HR

How does the immune system generate antibody diversity during B cell maturation?

Rearrangement of V, D and J gene segments using NHEJ

Which genome editing technology uses and RNA guide to target DNA sequences?

CRISPR-Cas9 technology

What are the 2 different ways to repair double stranded breaks (DSBs)?

HR (Homologous Recombination and NHEJ (Non Homologous End Joining).