Mutations

Question 1

What is a mutation?

Answer 1

A change in the DNA base sequence

Question 2

What is a point mutation?

Answer 2

A change in one of the bases

Question 3

What are the 4 types of mutations?

Answer 3

Substitution
Insertion
Deletion
Inversion

Question 4

What things cause mutations?

Answer 4

Chemicals
Radiation (X-rays)
UV light
Viruses

Question 5

Do silent mutations cause a change in amino acid?

Answer 5

No

Question 6

Does a nonsense mutation create a change?

Answer 6

Yes- a significant change

Question 7

What does a missense mutation cause?

Answer 7

A change in amino acid

Question 8

What does a frame shift mutation change?

Answer 8

Changes the number of nucleotides in the DNA sequence so its not divisible by 3

Question 9

How does a frame shift mutation create a significantly different protein?

Answer 9

Translation relies on reading triplets (codons)

Question 10

How can mutations sometimes not be a problem?

Answer 10

Amino acid may not be changed (degenerate)
Evolution- gives organisms a survival advantage- natural selection
Could occur in introns/non-coding DNA- gets spliced out anyway
May form the same shape- same bonds between the amino acid form
Mutations not in an enzyme’s active site (non-important part)

Question 11

Addition mutation?

Answer 11

One extra base being added to the sequence
All subsequent codons are altered- frame shift
Altered codons could code for different amino acids and result in a different sequence of amino acids- non-functioning protein

Question 12

Deletion mutation?

Answer 12

Causes a frame shit to the left
Can result in diff polypeptide chain and a non-functioning protein

Question 13

Substitution?

Answer 13

One base has been changed for a different base
Number of bases stays the same- no frame shift
Results in one codon changing- genetic code is degenerate so it may still code for the same amino acid and therefore have no impact

Question 14

Inversion?

Answer 14

A section of bases detach from the DNA sequence but when they rejoin they are inverted
The section of code is back to front
Results in different amino acids being coded for in this region