Mutations revisited

Question 1

Types of substitution mutations

Answer 1

1. silent mutations: no effect on amino acids, redundancy in genetic code
2. Missense mutation: different amino acid
3. Nonsense mutation: stop codon; most lead to nonfunctional protein

Question 2

Frameshift mutation

Answer 2

number inserted or deleted is not a multiple of three, resulting in improper grouping of subsequent nucleotides into codons

Question 3

Spontaneous mutation

Answer 3

errors in DNA replication or repair; minimal chance that mutation is advantageous, smaller chance that it confers to drug resistance

Question 4

Mutagens

Answer 4

physical/chemical agents that can cause mutations

Question 5

Reading frame

Answer 5

on mRNA; triplet grouping of ribonucleotides used by translation machinery during polypeptide synthesis