(no subject)

Karyotype: The number and appearance of chromosomes in the nucleus of a eukaryotic cell.
Polyploidy: Having more sets of chromosomes, like 21 instead of 7.
Tend to be infertile, but different species can be crossed to produce fertile offspring
cells tend to be larger

Aneuploidy: Having too many or not enough of an individual chromosome.

Trisomy: 21, Down Syndrome. Written 47, XX, +21
47, XXX: 2 out of the 3 are inactivated. Usually normal, but can have slight mental impairment and reduced fertility
47, XXY: Klinefelter, phenotypically male, but with some female characteristics
47, XYY: taller than 46, XY males
other trisomies are not viable.

Monosomy:
Turner syndrome
tend to be infertile--need two Xs to reproduce
some physical symptoms. some genes remain active on the deactivated chromosome in euploid individuals
Tend to be mosaics: if monosomy arises early and lots of daughter cells are aneuploid, more symptoms. if it arises later and fewer cells are aneuploid, then fewer symptoms.

Only viable monosomy in humans.

Chromosomes can have segments deleted.
They can have segments duplicated.
They can have segments inverted.
They can have segments translocated (detached and attached to another, non-homologous chromosome).