Lecture 9 - Genetic Toxicology

Question 1

Clastogen

Answer 1

Induces chromosomal aberrations; alters chromosome.

Question 2

Alkylating agents

Answer 2

Electrophiles which bind dna

• chemical warfare
• antisncer (kill cells, dna damage)
• apurinic sites

Question 3

Repair systems

Answer 3

Mismatch repair: base mispairs
Nucleotide excision repair: base addicts, crosslinks, base modifications
Base excision repair: base modificarions and single stranded breaks
Recombination repair system: single and double stranded breaks

Question 4

Base excision repair

Answer 4

3 enzymes:

1. Glycosylas removes tech damaged base (modified base or single stranded break=ak)
2. Dna polymerase adds one back
3. Dna ligase reattached

Question 5

Nucleotide excision repair

Answer 5

Addicts, crosslinks, modifications

Involves XPD enzymes; xerodrma pigmentosa

Question 6

Homologous recombination repair system

Answer 6

Switch over pieces of the strand to make functional strand again
Homogloeus repair proteins: p53, BRCA1/2

Question 7

Non-homologous end joining

Answer 7

DNA ligase tribes to stick the double stranded breaks back tgoether
However, unlike in homologous recombination (involves strand invasion), there is no perfectly matching template strand so some genes many be missing
Involves: r]brekagec and reunion
Recombination misrepair
Exchange theory