Mutations
Biology: Edexcel IGCSE, topic 4.3.10
Mutations
Mutations are random and permanent changes to the base sequence of existing genes. Mutations create new alleles.
What rate do mutations happen at?
- Mutations are rare.
- The rate of mutations can be increased by ionising radiation and some chemical mutagens (mutation-causing chemicals).
- Gamma rays, x-rays and ultraviolet rays are types of ionising radiation.
- Several chemicals in tobacco are mutagens.
Do mutations always affect the phenotype?
- Most mutations do not affect the phenotype.
- Mutations that do affect phenotype can have positive or negative effects.
Test yourself on Mutations
How frequently do mutations happen?
Which of the following are true of mutations?
Which of these does not describe mutations?