Lecture 3 DNA damage and repair mechanisms

Question 1

Which type of DNA damage is considered the most deleterious to the stability of the genome?

Answer 1

double-strand breaks

Question 2

The three excision-repair systems found in eukaryotes include: ______, which repairs T-G mismatches and damaged bases; _______, which repairs chemical adducts and thymine-thymine dimers; and _______, which repairs other base mismatches and small insertions and deletions

Answer 2

1. base excision repair
2. nucleotide excision repair
3. mistmatch repair

Question 3

Thymine-Thymine dimers are chemical adducts that develop in the DNA as a results of damage caused by which of the following?

Answer 3

UV radiation

Question 4

which of the following are enzymes that play a key role in the base excision repair of nucleotide mismatches and damaged bases?

Answer 4

glycosylases

Question 5

Which of the following mechanism can remove a nucleotide that is missing its nitrogenous base with the correct one?

Answer 5

base excision repair

Question 6

In which repair method is photolayse used?

Answer 6

Photoreactivation

Question 7

Which of the following are true regarding homologous recombination (HR)?

Answer 7

HR repairs double strand DNA damage, HR is used in gene editing systems, and during meiosis creates genetic diversity

Question 8

During the process of HR repair mechanism how is the nucleofilment that carries the damaged DNA strand to its complementary sister chromatid called?

Answer 8

Rad51

Question 9

Where does NHEJ usually occur?

Answer 9

in non-dividing cells

Question 10

In what DNA mechanisms does ATM function?

Answer 10

HR (homologous recombination)

Question 11

What is true regarding the cell cycle?

Answer 11

The G@ phase checkpoint ensures DNA replication has been completed correctly