16 Chromosomes & Karyotypes (copy)

Chromosome

A supercoiled piece of DNA wrapped around histone proteins; found in the nucleus

Homologous Chromosomes

A pair of similar chromosomes (one paternal, one maternal); have same banding patterns and same genes at same locations

Replicated Chromosome

A chromosome that has undergone DNA replication and contains two sister chromatids (looks like an "X" in shape)

Centromere

The constricted region where the two sister chromatids are joined on a replicated chromosome; where spindle fibers attach during mitosis or meiosis

Chromatid

One side of a replicated chromosome; sister chromatids are exact copies of each other

Banding Pattern

Areas of darker coloration when chromosomes are stained during karyotyping; each pair of homologous chromosomes has its own unique banding pattern

Karyotype

A chart of all the chromosomes of an organism (most humans have 23 pairs or 46 chromosomes total)

Diploid

An organism having two copies of each chromosome, one from each parent

Autosomes

Any chromosome other than a sex chromosome; humans have 22 pairs of autosomes

Sex Chromosomes

X and Y chromosomes (23rd pair in a human karyotype); determine gender

Monosomy

Having only one copy of a given chromosome in each somatic cell instead of two; missing one chromosome of a homologous pair

Trisomy

Having three copies of a given chromosome in each somatic cell rather than the normal two