3.8.1 Alteration of the Sequence of Bases in DNA Can Alter the Structure of Proteins Flashcards
Are all mutations bad?
No
Do all mutations have an affect on the phenotype?
No
Are all mutations the same size?
No
What is an addition mutation?
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
What is a duplication mutation?
One or more bases are repeated, frame shift to the right
What is an inversion mutation?
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
What is a translocation mutation?
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
What are the causes of mutations?
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