Inheritance Flashcards
Why is meiosis important in sexual reproduction?
Halves the number of chromosomes
Produces gametes
Meiosis
Special type of cell division by which gametes are formed
What is the advantage of meiosis to the next generation of individuals?
Produces variation as daughter cells aren’t identical
Results of meiosis
Leads to the production of 4 genetically different cells with only half the number of chromosomes
Genotype
Your genetic makeup (ie all of the alleles present in the cell nucleus)
Homozygous
2 identical alleles eg brown and brown or blue and blue
Heterozygous
2 different alleles eg brown and blue
Phenotype
The characteristic that is shown
Codominance
Both alleles contribute to the phenotype, so that both characteristics are present at the same time
Where do new alleles come from
Mutations
What are mutations
A change in the order of bases in DNA (ie a change in the genetic code)
What sorts of mutations are there
Gene mutations or chromosome mutations
Point mutation
A change in a single base
Chromosome mutation
Changes in chromosome structure of number
Dominant allele
Only 1 copy of allele is necessary for the characteristic to be shown
Recessive allele
2 copies of the allele are necessary for the characteristic to be shown
Meiosis- why must the dividing cell copy each chromosome
So that there is enough genetic material to be shared between the four daughter cells
