Stages of Meiosis

Question 1

How many times does nuclear division occur in meiosis?

Answer 1

= 2 times
= meiosis 1: homologous chromosomes are seperated from eachother
= meisois 2: sister chromatids are seperated seperated from eachother

Question 2

What happens in interphase?

Answer 2

= DNA is replicated (cell copies it’s chromosomes)
= organelles are copied, chromosomes are in their chromatin state, loose and open structure, not visible
=

Question 3

What happens in the first stage of meiosis 1, prophase 1?

Answer 3

= chromosomes condense + become visible
= homologous chromosomes link together forming chiasmata, bivalent
= crossing over takes place- alleles are exchanged
= nuclear membrane breaks down
= centrioles move to opposite ends of the cell, begins the formation of the protein spindle fibres
=

Question 4

What happens in metaphase 1?

Answer 4

= pairs of homologous chromosomes are lined up at the equator of the spindle apparatus

Question 5

What happens in anaphase 1?

Answer 5

= spindle apparatus shorterns
= homolgous chromosomes moves to opposite poles, the chiasmata between chromosomes break
=

Question 6

What happens in telophase 1?

Answer 6

= chromosomes are at the poles of the cell
= nuclear membrane reforms
= chromosomes return to chromatin state
=

Question 7

What happens in cytokensis?

Answer 7

= divdes into 2 cells
= haploid
=

Question 8

What happens in prophase 2?

Answer 8

= chromosomes condense + become visible again
= nuclear membrane breaks down
= spindle fibres begin to form
=

Question 9

What happens in metaphase 2?

Answer 9

= chromosomes are lined up at the equator of the spindle fibres

Question 10

What happens in anaphase 2?

Answer 10

= centromere of each chromosomes divides and the spindle fibres shortern
= chromatids are pulled to opposiye emds of the cell
=

Question 11

What happens in telophase 2?

Answer 11

= chromatids have reached poles of the cell, chromosomes
= nuclear membrane reforms
= chromosomes return to chromatin
= each cek

Question 12

What happens in cytokeneis 2?

Answer 12

= produces 2 haploid cells

Question 13

Why is meiosis descrived as reduction division?

Answer 13

= the chromosome number halves

Question 14

What else causes variation?

Answer 14

= when homologous pairs are alligned at the equator of the spindle fibres
= cannot predict whether paternal or maternal chromosome will end in which gamete
= independant assoryment