1. Mutations
3.29 Recall that mutation is a rare, random change in genetic material that can be inherited.
3.31 Understand that many mutations are harmful but some are neutral and a few are beneficial.
3.33 Understand that the incidence of mutations can be increases by exposure to ionizing radiation (e.g. gamma rays, X-rays and ultraviolet rays) and some chemical mutagens (e.g. chemicals in tobacco).

2. A mutation is a change in the DNA of a cell.
3.29 Recall that mutation is a rare, random change in genetic material that can be inherited.
A mutation is a change in the DNA of a cell.
It can happen in individual genes or in whole chromosomes.
Sometimes, when DNA is replicating, mistakes are made and the wrong nucleotide is used.
This results in a gene mutation and it can alter the sequence of the bases in a gene.
This then can lead to the gene coding for the wrong protein.

3. There are several ways in which gene mutations can occur:
Duplication of a nucleotide
Nucleotide inserted twice
Deletion of a nucleotide
A nucleotide is missed out
Substitution of a nucleotide
A different nucleotide is used
Inversion of a triplet
The sequence of the bases in a triplet is reversed.

4.   3.31 Understand that many mutations are harmful but some are neutral and a few are beneficial.
Sometimes a gene mutation can be advantageous to an individual.
This can be due to a random mutation.
For example: a bacteria can become resistant to antibiotics.

5. Gene mutations are random events that occur is all organisms.
3.33 Understand that the incidence of mutations can be increases by exposure to ionizing radiation (e.g. gamma rays, X-rays and ultraviolet rays) and some chemical mutagens (e.g. chemicals in tobacco).
Gene mutations are random events that occur is all organisms.
The rate at which they occur can be increased by a number of agents called mutagens.
Mutagens include:
Ionising radiation (UV light, X-rays and gamma rays)
Some chemicals
Mustard gas
Nitrous oxide
Cigarette smoke and tar
Some chemicals from burnt food