Lecture 15

Question 1

Recognise different kinds of mutations and predict their effects on amino acids sequence and protein function

Answer 1

Silent mutations
- Change in the sequence of nucleotide base, leaves DNA without huge change in amino acid
Missense mutation
- A single nucleotide change results in a codon that codes for a different amino acid
Nonsense mutation
- Shortening the polypeptide chain, creating an unfinished protein product.
Frameshift mutations
- occurs when a protein are drastically altered because of an insertion or a deletion of an amino acid

Question 2

Predict and explain the phenotypic effects of mutations in coding and non-coding regions

Answer 2

Phenotypic effect in non-coding regions can cause change as the non-coding region doesn’t affect the amino acid as no protein interactions occur here
Phenotypic effects in coding region can cause a change in the amino acid then in turn the protein because there is a physical change in this region whether there is a deletion of a nucleotide base sequence or complete change

Question 3

Describe the cause of mutations and give examples

Answer 3

1) spontaneous mutations (molecular decay) errors in replication
2) induced mutations (induced by various environmental factors known as mutagens

Question 4

Distinguish between germline and somatic mutations and their potential consequences

Answer 4

Germline - genetic disorders passed onto the offspring
Somatic - mutations that won’t be passed onto offspring, for example, genes that normally regulate cell growth and division, this will cause uncontrolled cell division that is characteristic cancer cells