3.8.1 Alteration of the Sequence of Bases in DNA Can Alter the Structure of Proteins

Question 1

Are all mutations bad?

Answer 1

No

Question 2

Do all mutations have an affect on the phenotype?

Answer 2

No

Question 3

Are all mutations the same size?

Answer 3

No

Question 4

What is an addition mutation?

Answer 4

When extra bases are inserted into the sequence
Causes a frame shift to the right
Whole sequence is affected
If three bases are added, there will not be a frame shift

Question 5

What is a duplication mutation?

Answer 5

One or more bases are repeated, frame shift to the right

Question 6

What is an inversion mutation?

Answer 6

Where a group of bases become separated from the DNA sequence and rejoin at the same position but back to front (inverse order)
Affects the amino acid sequence

Question 7

What is a translocation mutation?

Answer 7

Where a group of bases becomes separated from the DNA of one chromosome and become inserted into the DNA sequence of a different chromosome
This leads to an abnormal phenotype

Question 8

What are the causes of mutations?

Answer 8

Some are spontaneous with no outside interference
High energy ionising radiation e.g. xrays and UV
Chemicals e.g. nitrogen dioxide which alters DNA structure