4.3 - Mutations and meiosis Flashcards
What is a genetic mutation?
A change in the base sequence of chromosomes
Results in formation of new allele
What is a mutagenic agent?
A factor that increases the rate of gene mutation
Give two examples of types of mutation
Base deletion
Base substitution
How can mutations arise during meiosis?
Chromosome non-disjunction (failure of homologous chromosomes to separate) which arises spontaneously
Describe the cells that meiosis produces
4 haploid daughter cells that are genetically different (gametes)
How many nuclear divisions are there in meiosis and what is the starting cell?
Two nuclear divisions
Single parent diploid cell
Define haploid
Define diploid
How are genetically daughter cells produced during meiosis?
Independent segregation of homologous chromosomes
What is crossing over?
In meiosis 1 - homologous chromosomes pair, their chromatids wrap around each other and swap sections of allele
How is genetic variation further increased in meiosis?
Crossing over between homologous chromosomes
Random fertilisation of haploid gametes which produces new allele combinations
What is an allele?
Alternative version of the same gene
