Genetic variation

Question 1

Genetic mutation

Answer 1

A genetic mutation is a change to one or more nucleotide bases in the base sequence of DNA which results in the formation of a new allele
They can arise spontaneously during DNA replication

Question 2

Three types of genetic mutation

Answer 2

Substitution, Deletion and insertion

Question 3

Substitution

Answer 3

One base is replaced

Question 4

Deletion

Answer 4

One base is lost resulting in a frameshift

Question 5

Insertion

Answer 5

A base is added resulting in a frameshift

Question 6

Three results of genetic mutation

Answer 6

Silent , nonsense and missense

Question 7

Silent

Answer 7

No change in amino acid sequence due to degenerate code

Question 8

Nonsense

Answer 8

Results in formation of a stop protein level codon

Question 9

Missense

Answer 9

Results in a formation of a different amino acid

Question 10

Why might a genetic mutation cause an enzyme to stop working

Answer 10

1) A missense mutation is a result of a new amino acid
2) This amino acid changes the primary structure which changes the tertiary structure as bonds are in different places
3) This changes the shape of the enzymes active site
4)Enzymes active site and substrate are no longer complementary and cant form an enzyme-substrate complex

Question 11

Polyploid

Answer 11

Whole new sets of chromosomes

Question 12

Non-disjunction

Answer 12

Changes in number of individual chromosomes

Question 13

Mutagenic agent

Answer 13

Increases the rate of mutation
E.G UV radiation, Smoking, Carcinogen, X-ray