Damage, repair and recombo of DNA

Question 1

What are the 4 forms of DNA damage?

Answer 1

1. Deamination
2. Depurination
3. Pyridimine dimers
4. DNA breaks

Question 2

What are the 3 types of DNA repair mechanism?

Answer 2

1. Base excision repair
2. Nucleotide base excision repair
3. Homologous recombination

Question 3

What are the 5 enzymes involved in base excision repair?

Answer 3

1. DNA glycosylase
2. Apurinic/ apyrimidic endonuclease
3. Phosphodiesterase
4. DNA polymerase
5. DNA ligase

Question 4

What do pyrimidine dimers cause?

Answer 4

Arrest in DNA replication/ mis-reading of the DNA

Question 5

What does defective nucleotide excision repair machinery cause?

Answer 5

Xeroderma Pigmentosum- very sensitive to sunlight- induced skin cancer

Question 6

Which genes are involved in encoding proteins that are involved in the NER pathway?

Answer 6

XPA
XPC
XPF
XPD
XPG

Question 7

What do BRCA2 mutated cells do?

Answer 7

Become reliant on base-excision repair for DNA repair- can no longer rely on HR

Question 8

What is the double holliday junction?

Answer 8

Formed when homologous chromosomes cross over in meiosis

Question 9

What makes the initial cleavage in meiosis?

Answer 9

Spo11 endonuclease

Question 10

What resects the 5’ ends in meiosis?

Answer 10

Mre11 exonuclease