Meiosis

Fertilization

A union of 2 cells from 2 organisms

Ploidy Level

The number of sets of chromosomes determined by the parents

Haploid

Cells with one set of chromosomes

Diploid

Cells with two sets of chromosomes

Gametes

Haploid cells in animals

Zygote

Fertilized egg

Meiosis

Sexual reproduction that results in 4 genetically different haploid cells

Crossing Over

The exchange of chromosome segments between non-sister chromatids of homologous chromsomes

Prophase 1

When crossing over occurs

Recombinant

Chromosomes that are a mixture of maternal and paternal

Nonrecombinant

Chromosomes that are only paternal or maternal

Independent Assortment

Random arrangement of chromsomes in the center of the cell

Karyotype

The number and appearance of chromosomes

Nondisjunction

When a pair of homologous chromosomes fail to separate in meiosis

Trisomy 21

Down Syndrome, additional copy of chromosome 21