Meiosis

Question 1

What does meiosis produce?

Answer 1

Two daughter cells that are genetically different to eachother

Question 2

What does meiosis involve?

Answer 2

Two nuclear divisions to produce four haploid daughter cells from one diploid parent cell

Question 3

what are the two types of introducing variation?

Answer 3

Independent segregation of homologous chromosomes and
Crossing over of homologous chromosomes

Question 4

What happens during independent segregation?

Answer 4

1. Pairs of homologous chromosomes line up opposite eachother at the equator of the cell
2. It is random which side of the equator the maternal and paternal chromosomes of each homologous pair lie
3. These pairs are seperated so one of each homologous pair ends up in the daughter cell

Question 5

What does independent segregation allow?

Answer 5

A large number of possible combinations of chromosomes in the daughter cells produced

Question 6

How can the number of possible chromosome combinations be calculated?

Answer 6

2 to the power of n

Where n is the number of homologous pairs

Question 7

What happens during the crossing over of homologous chromosomes?

Answer 7

1. In meiosis 1 when homologous pairs line up opposite eachother at the equator parts of the chromatids can become twisted around eachother
2. This puts tension of the chromatids causing the pairs of chromatid to break
3. These broken parts of the chromatid recombine with another chromatid
4. This results in a new combination of alleles

Question 8

What is another way genetic variation occurs?

Answer 8

Through random fertilisation
As there will be (2n)2 possible combinations of chromosomes