ch 2 Flashcards
(28 cards)
what are somatic cells and diploid cell
contain 46 chromosomes
diploid chromosome has 2 chromate
what are gametes and haploid cell
contain 23 chromosomes
haploid each chromosome have 1 chromate
what is meiosis
formation of haploid cells from diploid cells
what is mitosis
formation of somatic cells
what are autosomes
the first 22 of the 23 pairs of chromosomes in males and females
what are sex chromosomes
remaining pair of chromosome
what is a triploidy
a zygote having three copies of each chromosome
what is a tetraploidy
four copies of each
what is chromosome aberrations
leading cause of mental retardation and miscarriage
what is aneuploidy
a somatic cell that does not contain a multiple of 23 chromosmes
a cell containing 3 copies of one chromosome is
trisomy - down syndrome
what is disjunction
normal separation of chromosome during cell division
what is nondisjunction
usually the cause of aneuploidy
failure of homologies chromosomes to separate normally during meisois or mitosis
what is down sydnrome
trisomy 21 auosomal aneuploidy
how many babies are affected with down syndrome
1- 800/1000 births
what are manifestation of down syndrome
mental retardation
characteristic facial features
cardiovascular problems
what do people with down syndrome at increased risk for
development of congenital heart disease, acute leukemia and alzheimers disease
the risk for having a down syndrome baby
risk increases with maternal age- may be related to age of oocyte
what is trisomy X
a female that has 3 X chromosomes
what are the symptoms of trisomy X
sterility
menstrual irregularity
mental retardation
symptoms worsen with each additional X
what is turner syndrome
females with only one X chromosome
what are manifestations of turner syndrome
short statue stocky built crest chest lack of breast development congenital heart defects
how can you treat turners syndrome
growth hormone
estrogen
what happens with 99% of turners syndrome
spontaneoulsy aborted in first trimester
