Meiosis and Karyotypes

meiosis

Type of cell division the body uses to create gametes. Consists of 2 cell divisions.

gamete

Sex cell (sperm, egg/ovum). Gametes are haploid 1n

mitosis

Type of cell division that produces identical diploid cells. Consists of 1 cell division.

Somatic Cells

Body cells 2n

haploid 1n

Cell that contains one set of chromosomes. 1n, 23 chromosomes.

diploid 2n

Cell that contains two sets of chromosomes 2n, 46 chromosomes

Fertilization

The process where a sperm and an egg combine to form a zygote/gertilized egg

zygote

fertilized egg

homologous chromosomes

chromosome that share the same genes, the same banding pattern, the same centromere location and are the same size. One member of each pair is maternal and one member is paternal.

chromatid

One of the two identical halves of a chromosome, joined together at the centromere

tetrad

Structure that consists of two homologous chromosomes that have paired up (4 chromatids) during prophase 1 of meiosis

crossing over

exchange genetic material (trading of parts) between two non sister chromatids in a tetrad during Prophase 1 or meiosis. Causes genetic variation in the gametes that are produced.

Independent assortment of chromosomes

Random lining up of homologous chromosomes during Meiosis 1. Results in the random inheritance of genes from parents. Causes genetic variation in the gametes that are produced.

spermatogenesis

The process of making sperm (form of meiosis). 1 cell splits into 4 sperm cells. Occurs in males in the testes. Begins in puberty.

Oogenesis

The process of making ova/eggs. Results in making 1 egg. Occurs in the ovaries. Begins in embryonic development but then stops until puberty.

karyotype

A diagram that shows all of the chromosomes in one cell.

monosomy

a chromosomal mutation (abnormality) where a person has one chromosome in one pair..

trisomy

a chromosomal mutation (abnormality) where a person has three chromosome in one pair..

nondisjunction

The failure of homologous chromosomes or sister chromatids to separate properly during Anaphase 1 or 2. Results in chromosomal mutations like monomies and trisomies

sperm

male gamete haploid 1n

ovum

female gamete haploid 1n

synapsis

Process where homologous chromosomes come together and pair up. Occurs during prophase 1 of meiosis.