W1D4H1&2 - Genome Organization, Chromosomal Abnormalities Flashcards
1
Q
telomeres
A
at ends of chromosomes
2
Q
centromeres
A
- near the center of the chromosome
- where spindle fibers attach
3
Q
p arm
A
- “p = petite”
- shorter arm of the chromosome
4
Q
q arm
A
- “mind your p’s and q’s”
- longer arm of the chromosome
5
Q
metacentric chromosome
A
arms are ~equal length
6
Q
submetacentric chromosome
A
arms are unequal in length
7
Q
acrocentric chromosome
A
- very short p arms. instead of protein-coding genes, have multiple copies of genes encoding ribosomal RNA
- chromosomes 13, 14, 15, 21, 22, and Y chromosome are acrocentric
- can participate in Robertsonian Translocation that can cause Down Syndrome or other congenital disorders
8
Q
chromosomal abnormality in Down Syndrome
A
- 3 copies of chromosome 21
- from meiotic non-disjunction or Robertsonian translocations
9
Q
Fluorescence In Situ Hybridization (FISH)
A
- uses specific probes to evaluate certain genes or entire chromosomes
- probe DNA w/ fluorescent dye base pairs w/ DNA that has been melted
10
Q
3 trisomies compatible with life
A
- trisomy 21 (Down Syndrome)
- trisomy 18 (Edwards Syndrome)
- trisomy 13 (Patau Syndrome)
11
Q
DiGeorge Syndrome (22q11 deletion syndrome aka CATCH-22 syndrome)
A
deletion in chromosome 22 C- cleft palate A-abnormal face T-thymic aplasia with T cell deficiency C - cardiac defects H - hypocalcemia
12
Q
Robertsonian translocation
A
- type of balanced translocation (mutual exchange of genetic material between 2 chromosomes - no net gain or loss of genetic material)
- q arms of acrocentric chromosomes fuse together
- essentially deletes 1 chromosome b/c p arms are tiny
13
Q
chromosomal inversions
A
- characterized by 2 breaks in a chromosome with end-to-end reversal of the 2 broken pieces
- 2 types: pericentric (involve the centromere), paracentric (do not involve the centromere)
