Meiosis - 7B

cells that contain half the number of chromosomes of a somatic cell.

cells that produce gametes

• ovary

• testes

organs (not organ systems) that produce gametes using germline cells (ovary and testes)

• produces 4 daughter cells

• each with have half the number of chromosomes of the original parent cell

• 2 nuclear divisions

appearance of chromosomes, homologous chromosomes synapse, and are crossing over between non-sister chromatids of homologous chromosomes may occur

homologous pairs of chromosomes line up independently at the spindle equator

homologous chromosomes are seperate and move towards opposite poles

chromosomes disappear. Nuclear membranes reform and the cell divides into two; each daughter cell has half the number of chromosomes as a parent

chromosomes reappear in each cell. each chromosome exist as two sister chromatids joined at the centromere.

each chromosome lines up at the spindle equator

centromeres are split and sister chromatids move to opposite poles.

chromosomes disappear. nuclear membranes reform and the cell divides into two.

• to produce gametes that are genetically distinct from each other

• things that increase genetic diversity are: crossing over, independent assortment

• where the chromatids overlap

• prophase 1

• when sections of the chromatids detach and rejoin. this results in genetic variation, exchanging of DNA which make the offspring genetically different to the parent.

• prophase 1

• the chromosomes that have crossed over.

• prophase 1

the random orientation of homologous chromosomes along the metaphase plate during metaphase 1