Meiosis, Genetics, and Chromosomes

Vocabulary flashcards covering cellular division, meiosis, chromosome structure, genetic inheritance, and errors in meiosis based on the lecture transcript.

Gametes

Sex cells, such as sperm and egg cells, that are the haploid products of meiosis.

Germ cells

Diploid cells located in the gonads that undergo meiosis to produce haploid gametes.

Gonads

The sex-neutral term for reproductive organs, specifically either an ovary or a testis.

Zygote

The single-celled, diploid fertilized egg created by the combination of a sperm and an egg before any mitotic division occurs.

Autosomes

The $22$ pairs of non-sex chromosomes present in human cells.

Sex chromosomes

The $23\text{rd}$ pair of chromosomes in mammals (such as XX or XY) that function differently than autosomes.

Alleles

Different versions of a specific gene.

Homologous chromosomes

A matched set of chromosomes containing the same genes in the same sequence, with one chromosome inherited from each parent.

Crossing over

The process occurring in late prophase I where homologous chromosomes align gene-for-gene and physically exchange sections of DNA.

Nondisjunction

An error in meiosis where chromosomes fail to separate properly, resulting in gametes with an abnormal number of chromosomes.

Down syndrome

A genetic condition resulting from a nondisjunction event that creates a trisomy of chromosome $21$.

Monozygotic twins

Identical twins who share the exact same genetic material due to a single fertilized zygote splitting after fertilization.

Dizygotic twins

Fraternal twins with unique DNA resulting from two separate eggs being fertilized by two separate sperm.

Apoptosis

Programmed cell death directed by the body.