Meiosis Flashcards
What is meiosis
Cell division to produce gametes
a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores (rather than mitosis that results in only 2 daughter cells)
What happens in prophase I
Chromosomes condense
Homologous pairs of chromosomes match up
Crossing over occurs
What is crossing over?
Crossing over is the exchange of genetic material between non-sister chromatids of homologous chromosomes during meiosis, which results in new allelic combinations in the daughter cells.
Which phase does crossing over happen in?
Prophase I
Why is crossing over important?
It increases genetic variation
What happens in Metaphase I
The pairs of homologous chromosomes line up along the middle of the cell
How is Metaphase I different in meiosis than mitosis
In meiosis there are pairs of chromosomes, in mitosis there is only 1 line of chromosomes
What happens in Anaphase I of meiosis?
Spindle fibres pull homologous chromosomes away from each other, to opposite ends of the cell
What happens in Telophase 1
Chromosomes gather at the poles of the cell Cytoplasm divides (cytokinesis)
What happens in Prophase II?
New spindle fibres begin to form around both the chromosome divisions
What happens in Metaphase II?
A single line of chromosomes lines up along middle of each cell
What happens in Anaphase II?
Spindle fibres pull sister chromatids to opposite ends of the cell
Centromeres split
What happens in telophase II?
Nuclear envelope forms around each set of chromosomes
Cytoplasm splits (cytokinesis)
4 new daughter cells are completed
What are the stages of meiosis
Interphase Prophase I Metaphase I Anaphase I Telophase I Prophase II Metaphase II Anaphase II Telophase II
What type of cells does meiosis create?
Gametes - sperm and egg cells
