2. Meiosis

Question 1

what does meiosis produce?

Answer 1

four genetically different gametes, which are haploid cells

Question 2

define chromosomes

Answer 2

a section of the genome, which is not attached at the centromere and is single

Question 3

define chromatids

Answer 3

cloned (identical) sections of chromosomes which are joined at the centromere, they split to form two chromosomes

Question 4

define homologous pairs of chromosomes

Answer 4

a paternal and maternal pair of chromosomes, they code for the same protein but have different versions

Question 5

what are daughter chromosomes

Answer 5

a pair of chromatids which have split, ending in different cells as a result of mitosis or meiosis

Question 6

name two ways that genetic variation can occur in meiosis

Answer 6

independent segregation of chromosomes, crossing over

Question 7

outline the stages of meiosis

Answer 7

Prophase one:
- chromosomes condense
- nuclear envelope breaks down
- centrioles at either poles of the cell
- homologous chromosomes bind along their length
- chiasmata forms between sister chromatids
- crossing over occurs at the chiasmata
- spindle fibres emerge from chromosomes

Metaphase:
- homologous chromosomes randomly line up at the equator
- independent segregation occurs

Anaphase:
- spindle fibres pull homologous chromosomes apart
- sister chromatids are still attached at the centromere

Telophase:
- sister chromatids arrive at poles and begin to decondense
- nuclear envelopes form around each nucleus , forming two haploid cells

process repeats, with chromosomes being pulled, producing four haploid cells