B1.14
- Created by: spud99
- Created on: 13-04-15 13:59
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- B1.14
- mutations
- change structure of gene
- spontaneous
- no external cause, mistake whilst DNA copied before cells divide
- caused by environment
- chemicals in tobacco
- chemicals in dying materials
- UV radiation from sunlight
- ionising radiation
- x-rays
- alleles
- different version of a gene that codes for the same characteristics BUT produce a slightly different version of them
- causes of genetic variation
- mutations
- formation of gametes
- fertilisation
- gametes
- sex cells
- female - eggs
- male - eggs
- each one genetically different
- 23 chromosomes
- made by meiosis of body cell
- 23 pairs of chromosomes in the body cell separate
- genetic variation during meiosis
- chromosomes swap pieces , different allele combination but same genes
- way two copies separate is random
- sex cells
- fertilisation
- random
- produces genetic variation
- 1 male gamete + 1 female gamete
- new individual with full number of chromosomes
- 1 male gamete + 1 female gamete
- mutations
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