meiosis

Question 1

What happens in meiosis?

Answer 1

• form of cell division that creates gametes that are haploid
• produces 4 genetically unique cells
• undergo 2 nuclear divisions

Question 2

aim of meiosis 1

Answer 2

To separate homologous pairs of chromosomes into two cells

Question 3

aim of meiotic division 2

Answer 3

to separate sister chromatids into 4 cells

Question 4

what is a diploid cell

Answer 4

total number of chromosomes that are able to form homologous pairs, represented at 2n

Question 5

what is a haploid cell

Answer 5

cell with chromosomes that cannot form homologous pairs, represented as n

Question 6

prophase 1

Answer 6

Homologous chromosomes line up together in their pairs, forming a bivalent

Question 7

When does crossing over occur and why does it create genetic variation?

Answer 7

occurs in prophase 1
- homologous chromosomes exchange material by crossing over sister chromatids which break and recombine, creating new combo of alleles

Question 8

when does independent segregation occur and why does it create genetic variation?

Answer 8

occurs in metaphase 1
homologous chromosomes line up randomly on each side of the equator, opposite their homologue
- new genetic combinations created

Question 9

Anaphase 1

Answer 9

• spindle fibres contract
• chromosome pairs are pulled apart by their centromeres

Question 10

prophase 11

Answer 10

Two new spindles form at right angles to original spindle
Chromatin condenses
Nuclear envelope breaks down

Question 11

why is meiosis important?

Answer 11

create cells with half number of chromosomes, increases genetic variation