Card Set Information
Higher Biology - Unit Two - Mutations
What is a mutation?
A change in the structure or amount of an organism's genetic material
What do you call an organism whose phenotype has been changed by the mutation in the genotype?
What are the three groups mutations can be put into?
Change in chromosome number
Change in chromosome structure
Change in gene structure
What kind of mutations can result in a change in chromosome number?
Non-disjunction of chromosome 21 - Down's syndrome
Non-disjunction of sex chromosomes - Turner's syndrome
Complete non-disjunction - Polyploidy
Name and describe the type of mutations that can result in a change in chromosome structure?
- a chromosome breaks but when it rejoins part of it is lost (genes are deleted)
- a chromosome breaks and when it rejoins genes from its homologous chromosome are added in
- when genes from one chromosome bread off and join on to another non-homologous chromosome
- when a chromosome breaks and some genes rotate 180° before it rejoins
Which of these mutations are lethal?
Name and describe the types of mutations that can result in a change in gene structure?
- when one nucleotide is removed
- when one nucleotide is added
- when two or more nucleotides are swapped over
- when one nucleotide is replaced by another
Which of these are point mutations?
Subsititution and inversion
Which of these are frameshift mutations?
Insertion and deletion
Mutations occur randomly and ____?
The majority of mutant alleles are...?
When do some mutant alleles show up?
If they are dominant or sex linked
Anything which causes a mutation is called a...?
The rate of mutations can be increased by mutagenic agents such as...?
Chemicals - eg mustard gas
Radiation - eg gamma, x-ray and ultraviolet
Mutations are a source of ...?