Meiosis
Is a special type of cell division necessary for reproduction.The meiosis process begins with one diploid containing two copies of each chromosome, and produces four haploid cells containing one copy of each chromosome.Each of the resulting chromosomes are a unique mixture of maternal and paternal DNA.
Interphase
The cell copies its chromosomes
Each chromosome has two sister chromatids held together with a centromere
Each chromosome has two sister chromatids held together with a centromere
Prophase 1
Chromosomes coil up and spindles form.
Homologous chromosomes come together matched gene by gene forming a tetrad
Crossing Over may occur when chromatids exchange genetic material -this occurs two or three times per pair of homologous chromosomes
Crossing Over results in new combinations of alleles on a chromosomes
Homologous chromosomes come together matched gene by gene forming a tetrad
Crossing Over may occur when chromatids exchange genetic material -this occurs two or three times per pair of homologous chromosomes
Crossing Over results in new combinations of alleles on a chromosomes
Metaphase 1
The centromere of each chromosome becomes attached to spindle fiber
The spindle fibers pull the tetrads to the equator of the spindle
Homologous chromosomes are lined up side by side as tetrads
The spindle fibers pull the tetrads to the equator of the spindle
Homologous chromosomes are lined up side by side as tetrads
Anaphase 1
homologous chromosomes separate and move to opposite ends of the cell
Centromeres do not split
This ensures that each new cell will receive only one chromosome from each homologous pair
Centromeres do not split
This ensures that each new cell will receive only one chromosome from each homologous pair
Telophase 1
The spindle breaks down and the chromosomes uncoil
The cytoplasm divides to yield two new cells
Each cell has half the genetic information of the original cell because it has only one homo- logous chromoso
The cytoplasm divides to yield two new cells
Each cell has half the genetic information of the original cell because it has only one homo- logous chromoso
Prophase 2
A spindle forms in each of the two new cells and the fibers attach to a chromosome
The chromosomes are pulled to the center of the cell and lined up randomly at the equator