Chapter 10 part 2 Flashcards
When a chromosome breaks, both DNA strands are severed at a location called a _______
chromosome break point
Detachment of all or part of one chromosome arm can lead to a _______; the broken fragment contains a telomere and some genetic material
terminal deletion
If any broken chromosome fragment is _______, it will likely be lost during cell division as it can’t attach to the spindle apparatus
acentric
_______ is an example of chromosome deletion and is caused by the loss of 5p15.2-5p15.3
cri-du-chat syndrome
_______ is the loss of an internal portion of a chromosome and results from 2 chromosome breaks
interstitial deletion
_______ is a series of conditions caused by interstitial deletion of multiple genes on chromosome 11
WAGR syndrome
an organism with one normal and one duplication homolog is a _______
partial duplication heterozygote
Unequal crossover does not occur often and most commonly occurs when repetitive regions such as _______ and _______ of homologs misalign
PMSA
PMSB
Large deletions and duplications are identified by a _______, which is the part of one homolog missing on the pairing partner
unpaired loop
Micro-deletions and micro-duplications can be identified by _______
FISH
Sometimes chromosome breakage leads to attachment of the wrong broken ends leading to _______ on the same chromosome or _______ to a nonhomologous chromosome
chromosome inversion
chromosome translocation
_______ when the centromere is outside of the inverted region
paracentric inversion
_______ when the centromere is within the inverted region
pericentric inversion
_______ have one normal and one inverted homolog
inversion heterozygotes
Crossing over within a paracentric inversion results in _______ and ______
dicentric chromosome
acentric chromosome
Crossing over within a pericentric inversion results in both duplicated and deleted regions in _______ of the recombinant products
both
Both paracentric and pericentric inversions result in _______ and _______
2 viable chromosomes
2 nonvialble chromosomes
What are the 3 different types of translocations?
1) unbalanced (one way transfer)
2) reciprocal balanced (two way transfer)
3) Robertsonian (fusion)
In reciprocal balanced translocations, _______ structure is formed at metaphase I of meiosis.
cross-like
Translocation heterozygotes are _______ because only half of alternate segregation leads to normal gametes
semi-sterile
If 2 pairs of chromosomes fuse by Robertsonian translocation, the number of chromosomes drops _______
2n-2
One type of robertsonian translocation between chromosome 21 and 14 is reponsible for _______
familial down syndrome
The DNA and associated proteins of a chromosome are called _______
chromatin
1/2 DNA and 1/2 protein
_______ are small basic proteins that tightly bind DNA
histone proteins
What are the 5 types of histone proteins?
1) H1
2) H2A
3) H2B
4) H3
5) H4
_______ are fundamental units of histone protein organization with two molecules of each histone (not including H1)
nucleosome core particles
- DNA around nucleosome is first level DNA condensation
How are nucleosomes assembled?
1) H2A and H2B form dimers
2) H3 and H4 form dimers
3) H3 and H4 dimers form tetramer
4) H2A and H2B associate with H3H4 tetramer to form octamer
The variable length between nucleosomes is called _______
linker DNA
the 30-nm fiber forms when the 10 nm fiber coils into a _______ with 6-8 nucleosomes per turn
solenoid
- second level of DNA condensation
What Histone stabilizes solenoids?
H1
Chromosome shape depends on the chromosome _______, composed of filamentous, non-histone proteins
scaffold
Chromatin loops are anchored to the chromosome scaffold by nonhistone proteins at sites called _______
MARs (matrix attachment regions)
_______ syndrome is found in partial deletion of heterozygotes for segment of chromosome 7 that contain duplicate copies of PMS
Williams-beuren
