Chromosomes and Karyotypes

Flashcards based on lecture notes about chromosomes and karyotypes.

Genetic Information

Hereditary information carried by genes, found within chromosomes in the nucleus.

Homologous Chromosomes

Chromosomes that are identical in size and shape and can be grouped in pairs.

Autosomes

All the chromosomes except the sex chromosomes.

Sex Chromosomes

X and Y chromosomes that determine the sex of an individual.

Karyotype

A photograph or drawing of an array (set) of chromosomes arranged in order of size and shape.

Chromosomal Formula for a typical female

46, XX

Chromosomal Formula for a typical male

46, XY

Chromosomal Formula for Trisomy 21 (Down Syndrome)

47, XY, +21

Chromosomal Formula for Klinefelter Syndrome

47, XXY

Chromosomal Formula for Turner Syndrome

45, XO

What does the presence of chromosome XX and XY determine?

Determines the sex of the individual.

What is the sex if the Karyotype has 2 X chromosomes?

Female, since it has 2 X chromosomes.

What abnormality is shown in the Karyotype if it has 47 chromosomes because of an extra 13th chromosome?

Trisomy 13

What does Trisomy mean?

There are 3 copies of a chromosome instead of 2.

What does Monosomy mean?

There is only 1 copy of a chromosome instead of 2.

What is a Karyotype?

A photograph or drawing of a set of chromosomes that are arranged by decreasing order of size.

How are chromosomes arranged in a karyotype?

Homologous chromosomes that are arranged in decreasing order of size, according to the position of the centromere.