DNA Replication and Repair Mechanisms

These flashcards cover key concepts related to DNA replication and repair mechanisms discussed in the lecture.

What is the purpose of the DNA polymerase proofreading activity?

To correct incorrect nucleotides incorporated during DNA replication.

What are the two main types of mutations discussed?

Incorporation of incorrect bases during DNA replication and chemical changes induced by external factors.

What is a mismatch in the context of DNA replication?

An incorrect nucleotide incorporated into the DNA strand during synthesis.

What type of damage does UV radiation cause to DNA?

Formation of thymine dimers, leading to distortions in the DNA structure.

What are apyrimidinic sites?

Sites in DNA where the nitrogen base has been lost completely.

Which enzyme is responsible for direct repair of thymine dimers in prokaryotes?

DNA photolyase.

What is base excision repair?

A mechanism that removes and replaces a single nucleotide with a damaged base.

What are the two types of nucleotide excision repair?

Global genome nucleotide excision repair and transcription-coupled nucleotide excision repair.

What happens during mismatch repair?

Proteins recognize and remove the mismatched base, and DNA polymerase replaces it with the correct one.

What is the main role of DNA ligase in DNA repair?

To join the DNA fragments created during repair processes.

What does the term 'translation DNA synthesis' refer to?

A mechanism where the cell continues DNA replication despite the presence of damage.