Chromosomes, Genes, Genotypes and Phenotypes

Chromosomes

Structures that organize and contain DNA in the cell.

Autosomes

The 22 pairs of chromosomes that are common in both males and females.

Sex chromosomes

The X/Y pair of chromosomes that dictate the genetic sex of the individual.

Allele

One of the different forms of a gene that can exist at a specific locus.

Genotype

An individual's genetic makeup or combination of alleles.

Phenotype

The expressed physical characteristic determined by the genotype.

Karyotype

A visual display of an individual's chromosomes arranged in pairs.

DNA length

If stretched out, DNA from one cell is approximately 6 feet long.

23 pairs

The total number of chromosome pairs in humans, consisting of 22 autosomes and 1 sex chromosome pair.

Eye color alleles

Different versions of a gene that determine the color of eyes, such as brown and blue.

Genetic sex

Determined by the sex chromosomes (X/Y) inherited from the parents.

30,000 genes

The approximate number of genes present in humans, located within the chromosomes.

Ovum

The female reproductive cell that contributes one set of chromosomes.

Sperm

The male reproductive cell that contributes one set of chromosomes.

Sex-linked traits

Traits that are associated with genes located on the sex chromosomes.

Expressed characteristic

The observable trait resulting from the interaction of genotype and environment.