Mutations

Question 1

Mutations at 2 different levels

Answer 1

1. Gene mutation

2. Chromosome aberrations

Question 2

Classes of gene mutations

Answer 2

1. Adaptive mutations

2. Spontaneous mutations

Question 3

What is an adaptive mutation?

Answer 3

Occurs in response to a particular environmental stimulus, and confers a selective advantage to the mutant

Question 4

What is a spontaneous mutation?

Answer 4

Arises independently of any external stimulus and may or may not confer a selective advantage to the mutant

Question 5

Multicellular eukaryotes are

Answer 5

somatic & gametic mutation

Question 6

Phenotypes mutations fall into categories

Answer 6

• Morphological
• Biochemical or nutritional
• Behavioural
• Regulatory

Question 7

Spontaneous mutation

Answer 7

arise from:

1. Errors in DNA replication
2. Spontaneous lesions

Question 8

Point mutation (characterized by base mutations)

Answer 8

Single base is substituted for another (tolerable for gene function)

Question 9

Frameshift mutation (characterized by base mutations)

Answer 9

Insertions and deletions within coding sequences will result in frameshift mutations that alter all subsequent codons downstream from the site of mutation

Question 10

Missense mutation (characterized by amino acids mutations)

Answer 10

A mistake in the DNA which results in the wrong amino acid being incorporated into a protein because of change, that single DNA sequence change, results in a different amino acid codon which the ribosome recognizes

Question 11

Nonsense mutation (characterized by amino acids mutations)

Answer 11

The substitution of a single base pair that leads to the appearance of a stop codon where previously there was a codon specifying an amino acid