Cellular Control

Question 1

What is a mutation

Answer 1

Mutations are random changes to the base sequence of DNA

Question 2

Mutations during mitotic division (somatic mutations)

Answer 2

Not passed on to offspring

Question 3

Mutations associated with meiosis

Answer 3

May be passed onto offspring

Question 4

Point mutation

Answer 4

One base pair is substituted for another

Question 5

Insertion or deletion

Answer 5

One or more nucleotides is inserted or deleted from a length of DNA. May cause a frame shift.

Question 6

Type of point mutation: silent

Answer 6

The genetic code is degenerate- have more than one base triplet. A change in base triplet where that triplet still codes for the same amino acid is called a silent mutation. Primary structure of protein unchanged.

Question 7

Missense (because of a change to one amino acid)

Answer 7

A change in base triplet that leads to change in amino acid codes for.

Change to primary structure of protein.

Question 8

Nonsense

Answer 8

A point mutation may alter a base triplet so that it becomes a termination (stop) triplet.

Result in shortened protein that will not function.

Question 9

Indel mutations: insertions and deletions.

Answer 9

If nucleotide bases are inserted or deleted, becasue they code is non overlapping and read from a fixed point in groups of three, all the subsequent base triplets are altered. Causes a frame shift.

Primary structure severely disrupted.

Question 10

Expanding triple nucleotide repeats

Answer 10

Some genes contain a repeating triplet. E.g. Cag cag cag.

In triple nucleotide repeats the number of CAG triplets is increased at meiosis.

Expanding triple repeat.
Type of insertion.