Induced Mutations

Question 1

Introduction to Induced Mutations

Answer 1

Step 1: mutagen makes a lesion

Step 2: DNA replication and/or DNA repair turns it into a mutation

Question 2

EMS

Answer 2

EMS sticks to G’s
A damaged G may resemble an A which would result in a GC to AT bp substitution
EMS is used to deliberately cause mutations

Question 3

Benzo[a]pyrene

Answer 3

Found in cigarettes
Sticks to a G and causes a lesion in the DNA helix
DNA Pol won’t recognize the damaged G and will default to dATP
Cigarettes cause lung cancer

Question 4

Radiation

Answer 4

X-rays and gamma rays break DNA

Question 5

NHEJ System

Answer 5

Non-homologous end joining (NHEJ) is a pathway that repairs double-strand breaks in DNA

Question 6

Another Function of Telomeres

Answer 6

Shield natural chromosome ends from NHEJ proteins

Question 7

What happens when two dsDNA breaks in the same nucleus?

Answer 7

Incorrect repair and rearrangement