Spontaneous Mutations

Question 1

Mutation

Answer 1

A heritable change in the DNA; the process by which such a change occurs

Question 2

Mutant

Answer 2

A cell or organism carrying a mutation

Question 3

How do mutations come to be?

Answer 3

They can be either spontaneous or induced due to an external factor

Question 4

Mutagen

Answer 4

A physical or chemical agent that raises the frequency of mutation above the spontaneous rate

Question 5

Deamination of Cytosines

Answer 5

A spontaneous reaction turns cytosine into uracil

Happens to 100 bases/cell/day

Question 6

Events of Deamination of Cytosines

Answer 6

Deamination of cytosine within DNA turns a GC bp into a GU bp
During DNA replication, one template will use a dCTP and the other will use a dATP
After another DNA replication, the result is a GC to AT bp substitution

Question 7

Events of Base Excision Repair

Answer 7

Step 1: DNA repair enzymes recognize defective bases and remove them
Step 2: Other DNA repair enzymes fix the AP site

Question 8

AP Sites

Answer 8

Places in DNA missing a base

Apurinic or apyrimidinic

Question 9

The Timing of Base Excision Repair

Answer 9

Prompt repair of the lesion will stop a mutation from occurring
Delayed repair of the lesion will cause a mutation

Question 10

Replication Slippage at Repeat DNA

Answer 10

If DNA pol falls off while in a repeat then the strands anneal incorrectly and when DNA pol returns loops form
If daughter strand loops out = insertion of base pairs
If template strand loops out = deletion of base pairs