TOPIC 8.1 gene mutations

Question 1

addition

Answer 1

1 or more bases added
frameshift right - entire base triplet seq changed

if 3 added = no frameshift

Question 2

deletion

Answer 2

1 or more bases deleted
frameshift - diff triplets & coded a.a = diff protein bc gene read in wrong 3 base grps

Question 3

substitution: silent

Answer 3

diff codon for same a.a bc genetic code degenerate - certain codons code for same a.a

Question 4

substitution: missence

Answer 4

codon for diff a.a - polypep structure differs in 1 a.a

Question 5

substitution: nonsense

Answer 5

premature stop codon

Question 6

duplication

Answer 6

1 or more bases repeated - right frameshift

Question 7

inversion

Answer 7

grp of bases separate from seq and rejoin in reverse order at same position

Question 8

translocation

Answer 8

base grp seperated from seq on 1 chrom becomes inserted into seq on diff chrom
abnormal phenotype

Question 9

mutagenic agent

Answer 9

inc risk mutation by acting as base, changing bases, changing DNA structure

1. radiation disrupts DNA structure
2. chemicals (eg. NO2) changes DNA structure or interferes w transcription

Question 10

Explain how a single base substitution causes a change in the structure of
this polypeptide (3)

Answer 10

change in a.a seq/1y structure
change in H bonds
changes tertiary structure
substrate not complementary to enzyme = no ES complex