3b: Meiosis

Question 1

Meiosis definition

Answer 1

is the division of the nucleus that results in the formation of haploid gametes
from a diploid gametocyte

Question 2

Homologous chromosomes are…

Answer 2

• same size
• same centromere position
• same sequence of genes at the same loci

Question 3

where do chiasmata form

Answer 3

at points of contact between the non-sister chromatids of a
homologous pair and sections of DNA are exchanged

Question 4

how does meiosis provide variation

Answer 4

• when homologous chromosomes pair up, the crossing over of DNA is random and produces genetically different
  recombinant chromosomes. (chiasmata form at points of contact)
• Crossing over can result in new combinations of the alleles of these genes.
• independent assortment

Question 5

what is independent assortment

Answer 5

• when spindle fibres line up at the equator the orientation of the pairs of homologous chromosomes at the equator is random
• Each pair of homologous chromosomes is positioned independently of the other pairs, irrespective of their maternal and paternal origin.

Question 6

What happens in meiosis II

Answer 6

Each of the two cells produced in meiosis I undergoes a further division during which the sister chromatids of each chromosome are separated