Genetic+HW+PK

Chromosome Homework by Patricia Kelley



Name chromosome deletion syndromes.
 * Changes in Chromosome Number
 * Vocab:
 * **meiosis:** a process of cell division to produce cells that have half the normal number of chromosomes, those cells are called eggs and sperm. In real life human normal cells have 46 chromosomes and eggs and sperm have 23.
 * **nondisjunction**: if this occurs during meiosis I (the first cell division), it is when both members of a pair of chromosomes go into the same daughter cell (left side of figure below). If this occurs during meiosis part II (the second cell division), the identical sister chromatids fail to separate and both sister chromatids go into the same gamete.(right side of figure below)[[image:nondis.jpg]]
 * **trisomy** this occurs if a sex cell has 24 chromosomes instead of 23 and is fertilized with a normal sex cell with 23 chromosomes, the result is there is an extra chromosome, 47 instead of 46. There will be three copies of one chromosome instead of the normal 2.
 * **monosomy:** this occurs when a sex cell with 22 chromosomes instead of the normal 23 is fertilized with a normal sex cell, the result is a cell missing a chromosome, with only 45 chromosomes instead of 46. For one chromosome type one chromosome is present in a single copy instead of the normal 2.
 * **Barr body:** an inactive X chromosome in all female cells.
 * **Down Syndrome:** 47, trisomy 21 when a person has three copies of chromosome 21. Example of TRISOMY.
 * T**urner Syndrome**: 45, XO when a person only has one X sex chromosome (ends up to be a woman that does not go through puberty--the ovaries and uterus are small and underdeveloped--can lead fairly normal lives with female hormone supplements). Example of MONOSOMY.
 * **Klinefelter Syndrome**: 47, XXY when a male has two X chromosomes and one Y chromosome, usually has very subtle symptoms -- some slight female physical characteristics, learning disabilities, male hormone therapy can help
 * **Poly-X Females:** 47, XXX when a female has more than two X chromosomes and 2 Barr bodies (2 inactivated X chromosomes) in the nucleus, the woman has subtle symptoms (slow speech) and a tendency to be tall and thin.
 * **Jacobs Syndrome**: 47, XYY males (symptoms: persistent acne, speech and reading problems, more like to be criminally aggressive). Male, and taller than average.
 * What are the two types of chromosomes and how many of each do we have in every cell?
 * Two types of chromosomes are autosomes (non sex chromosomes) and the sex chromosomes (are X and Y). Males have one X and one Y. Females have two Xs. Males and females have 22 pairs of autosomes. 23 pairs in all all. 22 pairs of autosomes and 1 pair of sex chromosomes.
 * Describe process that can change the normal number of chromosomes in a cell?
 * Nondisjunction can change the number of chromosomes in sperm and eggs. Either an extra chromosome (trisomy) or a missing chromosome called monosomy.
 * Name chromosome disorders due to an abnormal number of autosomal chromosomes.
 * Down syndrome may occur.
 * Name chromosome disorders due to an abnormal number of sex chromosomes.
 * Turner syndrome and Klinefelter syndrome, Poly X and Jacobs syndrome occur due to an abnormal number of sex chromosomes.
 * Changes in Chromosome Structure
 * Vocab:
 * **chromosome deletion**: when the end of a chromosome breaks off and is deleted
 * **chromosome duplication**: occurs when a chromosomal segment is found multiple times within the same chromosomes
 * **Chromosome inversion**: a segment of a chromosome when it is turned 180 degrees
 * **chromosome translocation**: the movement of a chromosomal segment from one chromosome to another
 * **Williams syndrome**: DELETION occurs when chromosome 7 loses a tiny piece. Children with this syndrome look like pixies they have turned up noses, wide mouths, a small chin and large ears.
 * **Crit du Chat (cat's cry) syndrome**: DELETION occurs when chromosome 5 loses a tiny piece. They make a cat like cry as infants. Small head, mental retardation, facial abnormalities.
 * **Alagille sydnrome**: TRANSLOCATION a translocation from chromosome 2 to chromosome 20, a distinctive face, other mild symptoms
 * **Chronic myelogenous leukemia:** TRANSLOCATION A cancer due to a translocation of part of chromosome 22 to chromosome 9
 * **Burkett lymphoma**: TRANSLOCATION A cancer due the translocation of a part of chromosome 8 part to chromosome 14
 * Williams Syndrome, Cri du Chat Syndrome
 * Name chromosome translocation syndromes.
 * Alagille Syndrome, Burkett Lymphoma Syndrome and Chronic Myelogenous leukemia.