Meiosis 1

Question 1

Meiosis 1: often called _______ ________ because?

Answer 1

reduction division
-chromosome number is reduced by half from diploid 2n to haploid n

Question 2

Prophase 1
-what do chromosomes do?
-what happens to nuclear membrane and centrioles?
-what happens to homologus chromosomes
-what happens to pairs
-what is crossing over? what does it increase?

Answer 2

-thicken and condense (goes from chromatin to chromosomes)
-dissolves, migrate to opposite poles
-homologus chromosomes pair up aligned gene by gene to form TETRAD
-pairs are zipped together on the synapsis (place on spindle fibre where they are side by side)
-crossing over is when non sister chromatids of a homologus pair intertwine and break apart exchanging genetic material.
-this increases genetic diversity

Question 3

Metaphase 1
-what do homologous chromosomes do?
-what do the pairs do?
-what is independent assortment, and what does it increase?
-how many pairs of chromosomes line up at the plate in meiosis? how does this make it different from mitosis

Answer 3

attach to microtubules
-line up at the equatorial plate, each being made of one maternal and one paternal chromosome
-each pair will align at the metaphase independent of other pairs, increasing genetic diversity
-23 pairs of chromosomes that line up at the plate, which differs as mitosis has 46 pairs lined up there

Question 4

Anaphase 1
-what do homologus chromosomes do
-what is the process known as

Answer 4

-they seperate and move to oppopsite poles
-segregation

Question 5

Telophase 1
-what forms and where?
-unlike motosis, what happens to the resulting cells
-each daughter cell is ______
-when does complete cytokinesis occur, forming what?

Answer 5

-nuclear membrane forms around the chromosomes within each of the 2 cells
-the 2 daughter cells are not identical
-haploid
-it occurs before Meiosis 1 and 2, simultaneously, forming 2 haploid daughter cells