Genetic Disorders-Bickmen Flashcards
Somatic cells
contain 46 chromosomes
23 pairs
diploid
Gametes
contain 23 chromosomes
haploid
one member of each chromosome pair
Meiosis
formation of hapliod celld from diplios cells
Autosomes
the first 22 of the 23 pairs of chromosomes
the two members of each pair are idetical (homologus)
sex chromosomes
remaining pair of chromosomes
karyotype
ordered display of chromosome
(Picture )
chromosomes mutations def
any inheritied alteration of genetic material
types of mutations
base pair subsitiution
frame shift mutation
base pair mutation
one base pair is substituted for another
- silent
- missense
- nonsense
frame shift mutation
insertion or deletion of one or more base pairs
causes a change in the readin frame
Non-mutation chromosomal alterations
- Polymorphisms
- Epigenetic changes
- Alterations in non-coding RNAs
- Translocation (leukemia, philly chomosome)
polymorphisms
Non-mutation alteration
- abnormal number of copeis of one or more sections of DNA
- single nucleotide polymorphisms (SNP)
what is the difference between an SNP and point mutation
point mutation occurs in less than 1% of the population
SNP occurs in more that 1% of the population- common varation in single mucletotide
epigenetics
non muation alteration
non DNA changes
alterations in gene or protein expression
environmental
alterations in Non-coding RNAs
non-mutatoin alteration
regulating genes that do not code for proteins
translocation
- non mutation alteration
- interchanging of material between non homologous chromosomes
- when two chomosomes beak and the segments are rejoined in an abnormal arrangement
Euploid Cells
- Has the normal number of chromosomes
- Different for hapliod vs. diploid
Polyploid cell
cell has a multiple of 23
examples of polyploid
- Triploidy: three copies of each chromosome (69= 3x23)
- Tetraploidy: four copies of each chromosome (92=4x23)
both are embryonic lethal (10% of miscarriges)
Aneuploidy
a somatic cell that does not contain a multiople of 23 chromosomes
types of aneuploidy
- trisomy: 3 copies of one chromosome is thrisomic
- monosomy: 1 copy of any chromosome in monosomic
monosomy is usually lethal
better to have …
too many than too few chromosomes
disjunction
normal separation of chromosomes during cell division
Nondisjunction
- usally in aneuploidy
- failure of the homologous chromosomes or sister chromatids to separate in meiosis or mitosis
chromosome aberrations
- Nondisjunction
- aneuploidy
- polyploid
If a human fetus has 45 chromosomes in it’s cell it would be called a___ and would be a result of _____
Aneuploidy
Monosomy
Types of autosomal aneuploidy
- Trisomy 13, 18, 21
2.
Trisomy 13
Autosomal Aneuploidy
Patau Syndrome
- Polydactyly
- Mental retardation
- microcephaly
- usually leathal early in life due to heart deformities
- Dental Features: celft lip and palate