Chromosomes+DB



•	Changes in Chromosome Number •	Vocab:

nondisjunction-both members of a homologous pair go into the same daughter cell

trisomy-one type of chromosome is present in three copies after an egg with 24 chromosomes is fertilized

monosomy- one type of chromosome present after an egg with 22 chromosomes is fertilized with a normal sperm

Barr body- when one of the X chromosomes becomes a darkly staining mass of chromatin

Down Syndrome- trisomy in the chromosome 21

Turner Syndrome- a person has only one sex chromosome, X

Klinefelter Syndrome- two chromosomes X and one Y

Poly-X Females- more than two X chromosomes and extra Barr bodies in the nucleus

Jacobs Syndrome- two Y chromosomes and one X

•	What are the two types of chromosomes and how many of each do we have in every cell? Two types of chromosomes are the X and Y chromosome, and depending on whether a person is male or female, they will have one of each type, or two X's.

•	Describe process that can change the normal number of chromosomes in a cell? Nondisjunction changes the chromosome number in a cell when both parts of a homologuous pair go into the same daughter cell.

•	Name chromosome disorders due to an abnormal number of autosomal chromosomes. Down Syndrome

•	Name chromosome disorders due to an abnormal number of sex chromosomes. Turner Syndrome and Klinefelter syndrome

•	Changes in Chromosome Structure •     Vocab:

deletion-an end of a chromosome breaks off or two breaks lead to loss of a segment

duplication-presence of a chromosomal segment multiple times in the same chromosome

inversion- a segment of a chromosome is turned 180 degrees

translocation- movement of a chromosome segment from one chromosome to another nonhomologous chromosome

Williams syndrome- chromosome 7 loses a small end piece

Crit du Chat syndrome-chromosome 5 loses an end piece

Alagille sydnrome- deletion on chromosome 20

Chronic myelogenous leukemia-translocation from part of chromosome 22 to chromosome 9

Burkett lymphoma- translocation from part of chromosome 8 to chromosome 14

•	Name chromosome deletion syndromes. Alagille syndrome and Crit du Chat syndrome

•	Name chromosome translocation syndromes. Chronic myelogenous leukemia and burkett leukemia