DNA Repair Flashcards Preview

MCBG > DNA Repair > Flashcards

Flashcards in DNA Repair Deck (22):
1

How is DNA damaged?

Exogenous- ionising radiation, alkylating agents, UV light, anti-cancer agents
Endogenous- DNA replication errors, V(D)J recombination, free radicals

2

What is the response to DNA damage in the body?

Senescence
Cell cycle transition
Apoptosis
Transcription
DNA repair

3

What is the signalling cascade of DNA damage?

Signal
Sensor
Transducer
Effector

4

Where and what are cell cycle checkpoints?

After G1 before S
After G2 before mitosis
Temporary arrest (time for DNA damage to be repaired)

5

What is senescence?

Permanent cell cycle arrest

6

What is apoptosis?

Cell death

7

What is the repair if there is a single strand break?

Base excision repair

8

What is the repair of there is a CPD?

Nucleotide excision repair

9

What repair occurs if there is a double strand break?

Recombinational repair

10

What repair occurs if there is insertion or deletion due to mismatch between AG?

Mismatch repair

11

What is a base excision repair?

DNA glucosylase removes incorrect nucleotide
AP endonuclease and deoxyribosephosphodiesterase allow space so correct nucleotide can be added using DNA polymerase and ligase

12

What is a mismatch repair?

Endonuclease and exonuclease is used to remove short strand of incorrect DNA
DNA polymerase and ligase then synthesise DNA again correctly

13

What is nucleotide excision repair?

Damaged area is cut
Repair is synthesised

14

How is a double strand break repaired?

Proteins recruited to protect ends
Proteins recruited to remove DNA damaged components
Ligase sticks the two broken ends back together

15

What is cancer?

Uncontrollable cell growth

16

What allows cancer to develop?

Suppression or alteration of DNA damage response

17

What syndromes are caused by mismatch repair?

Lynch syndrome
Colorectal cancer

18

Why is p53 important?

Mutated in many cancers

19

What can develop within a tumour?

Subclones

20

What is a heterogenous tumour?

A tumour with sub-clones making it more difficult to treat as may be therapy resistance and lead to clonal expansion

21

What is the basis of cancer killing?

DNA damage e.g. Camptothecin

22

What are the side effects of cancer treatments?

Radiation- Skin problems, fatigue, heart problems
Chemotherapy- Hair loss, fertility problems, nausea