Sexual reproduction

Gametes

Reproductive cells that fuse during fertilization.

Meiosis

Cell division producing haploid gametes from diploid cells.

Sperm

Small, motile male gamete in sexual reproduction.

Egg

Large, non-motile female gamete in sexual reproduction.

Diploid

Cells with two homologous chromosome sets.

Haploid

Cells with one complete set of chromosomes.

Homologs

Maternal and paternal chromosome pairs.

Alleles

Variant forms of a gene.

Zygote

Diploid cell formed from gamete fusion.

Meiosis I

First meiotic division; homologs segregate.

Meiosis II

Second meiotic division; sister chromatids separate.

Bivalent

Pair of homologous chromosomes during meiosis.

Crossing Over

Exchange of genetic material between homologous chromosomes.

Chiasma

Point where homologous chromosomes cross over.

Cohesin Proteins

Proteins that hold sister chromatids together.

Random Assortment

Independent segregation of maternal and paternal chromosomes.

Nondisjunction

Failure of homologs or sister chromatids to separate.

Aneuploidy

Condition of having an abnormal number of chromosomes.

Trisomy 21

Genetic disorder caused by an extra chromosome 21.

Oocytes

Cells that develop into eggs.

Synaptonemal Complex

Structure that holds homologous chromosomes together.

Fertilization

Process of sperm and egg fusion.

Ca2+ Release

Triggers egg development after sperm fusion.

Zona Pellucida

Protective layer surrounding the egg.