Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Genetics 1 > Topic 7: Chromosome Alterations > Flashcards

Topic 7: Chromosome Alterations Flashcards

(76 cards)

Start Studying
1
Q

___________: contain a single chromosome within an arbitrary region that is not bound by any membranes

A

chromosomal territories

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how do we visualize our chromosomes?

A

with a karyotype! (an individual’s complete set of chromosomes- can now be made into a picture!)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

chromosomes 1-22 are ________

A

autosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

chromsome 23 is a ___________

A

sex chromosome (X or Y)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

chromosomes are divided at the centromere into _______________

A

chromosome arms (usually unequal lengths)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

short arm = (________)

A

p arm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

long arm = (________)

A

q arm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

_________ chromosomes have a centromere near the middle

A

metacentric

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

______ chromosomes have a centromere nearer to one end

A

submetacentric

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

_________ chromosomes have centromeres at one end

A

acrocentric

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

_________ chromosomes have a terminal centromere

A

telocentric

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

________ condensation results in the banding patterns on chromosomes

A

chromatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

_______: regions of lesser compaction, actively transcribed chromatin

_________: regions of higher compaction, less gene transcription

A

euchromatin

heterochromatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

_________: when chromosomes and sister chromatids fail to separate properly

A

nondisjunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

chromosome numbers that are a multiple of the haploid number (2n, 3n, 4n…) are ______

A

euploid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

if we add or remove a chromosome, it alters the euploid number and generates an _______

A

aneuploid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

____________in germ-line cells causes aneuploidy

A

nondisjunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

nondisjunction in germ-line cells results in the failure of homologous chromosome separation in ________

A

meiosis I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

________ (2n+1): three of one chromosome instead of a homologous pair

A

trisomy (trisomic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

_______ (2n-1): a single copy of the chromosomes instead of a homologous pair

A

monosomic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

nondisjunction in germ-line cells results in the failure of sister chromatid separation in _______

A

meiosis II (typically follows after a normal meiosis I)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

aneuploidy alters gene dosage, which two men worked on this concept? and with what plant?

A

Albert Francis Blakeslee and John Belling worked on the Jimson Weed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

true/false: aneuploidy changes the gene dosage of ALL the genes on the affected chromosome

A

true!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

in diploid organisms, gene dosage is ____%
monosomic: ______%
trisomic: _________%

A

100
50
150

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
true/false: plants aren't as tolerant to changes in gene dosage compared to animals
false! they are!
26
where are the three most common chromosomes for trisomy in humans? How many total opportunities for trisomy are there?
trisomy 13, 18, 21 potential for 24 different kinds of trisomy (often see them in sex chromosomes!!)
27
when does trisomy 21 (Down Syndrome) occur? in what meiotic stage? what is trisomy 21 linked to?
reaches synapsis in prophase I, then stops (90% of trisomy 21 cases were a result of meiosis I nondisjunction) linked to the age of the mother children have two copies of maternal C21, and one copy of paternal C21
28
what are two examples of gene dosage differences in humans with missing/extra sex chromosomes? (female)
turner syndrome (X0) triple X syndrome (XXX)
29
X-inactivation mosaicism occurs from ______ nondisjunction: occurs during embryogenesis early in development
mitotic (example: Turner syndrome)
30
____________ disomy: both copies of the homologous chromosome pair are derived from the same parent
uniparental (requires nondisjunction of the same chromosome in both the eggs and the sperm!! (super rare!!))
31
________: the presence of three or more sets of chromosomes
polyploidy (very common in plants!!)
32
________: have chromosomes derived from a single species
autopolyploids
33
______: have chromosomes derived from multiple species
allopolyploids
34
polyploidy results from....
meiotic nondisjunction (2n egg + 1n sperm) mitotic nondisjunction (doubles chromosome number)
35
what are the consequences of commercial polyploidy in food?
fruit and flower size increases, reduced fertility (seedless fruits), increase in heterozygotes relative to diploids
36
development of wheat: the union of diploid genomes of _____ ancestral species
three
37
true/false: changes to chromosome structure can result in the loss/addition of genes
true! causes gene dosage imbalances, animals are greatly affected by these abnormalities
38
why are chromosome mutations important?
a common source of genetic variation, a major cause of genetic disorders and conditions, a cause of infertility
39
what are the main four kinds of mutations?
deletions, duplications, inversions, translocations
40
what are three things that can lead to chromosome breaks during DNA synthesis/crossing over in meiosis?
external mutagens/chemicals/radiation transposable bits of DNA (mobile) recombination errors
41
true/false: when a break happens, segments of the chromosome can be lost
true
42
partial chromosome deletion: both strands of DNA are severed at the _____________
chromosome breakpoint (they retain their chromatin structure, can re-adhere to each other)
43
______ deletion: chromosome end breaks off, containing telomere and additional genetic material
terminal deletion
44
terminal deletion leaves a chromosome fragment ______
acentric (without a centromere)
45
cri-du-chat syndrome results in a partial __________
partial deletion heterozygote (one chromosome is wildtype, and the homolog has a terminal deletion)
46
_____________: The pattern of inheritance in which a single recessive allele is inherited but is still expressed
pseudodominance
47
________ syndrome displays pseudodominance because the allele on the normal homolog will be phenotypically expressed, instead of the partial deletion
cri-du-chat
48
_________ deletion: two chromosomal breaks, resulting in the loss of an internal segment
interstitial deletion (results in a shorter than normal chromosome)
49
what is the human example of interstitial deletion?
WAGR syndrome
50
if a segment is deleted from both homologous chromosomes, it is a _______
deletion homozygote
51
_________- are repeated segments on a chromosome, can arise form unequal crossing over
duplications
52
unequal crossovers result in what two main categories?
partial duplication partial deletion
53
an individual with one wildtype chromosome and one with duplicated material is a partial _________
duplication heterozygote
54
true/false: unequal crossover isn't rare and occurs when homologs misalign during prophase I
false! it is rare!
55
what is an example of human duplications?
Williams-Beuren syndrome
56
in Williams-Beuren syndrome, what are the effects of the shortened partial deletion chromosome? the lengthened partial duplication chromosome?
shortened: causes the phenotypic effects in the disorder lengthened: has no negative phenotypic effects
57
how do we detect deletions and duplications? two ways
using a microscope, can usually see them if they're 100 000- 200 000 basepairs or more look for unpaired loops
58
how/when do unpaired loops form?
form during the mismatch of homologous pairs during prophase I
59
when do chromosome inversions happen?
when two "sticky ends" join back to the broken chromosome, but in the wrong orientation
60
__________ inversion: beside the centromere
paracentric inversion (doesn't include the centromere)
61
_________ inversion: around the centromere
pericentric inversion (includes the centromere)
62
_________ heterozygotes have one wildtype chromosome and one inverted chromosome
inversion heterozygotes
63
true/false: inversions usually only affect one member of the homologous pair
true!
64
________: has two centromeres
dicentric
65
_______: has no centromeres
acentric
66
during ___________, a dicentric bridge forms as the dicentric chromosome is pulling towards both poles of the cell (breaking it due to tension)
anaphase I
67
in a pericentric inversion, crossing over occurs...
inside the region of the inversion loop
68
inversions create _______ suppression
crossover suppression
69
when a chromosome breaks and the fragment reattaches to a different chromosome, or to a new spot on the same chromosome, ________ has occurred
translocation
70
________ heterozygotes have one wildtype chromosome and one altered chromosome
translocation
71
_________ translocation: reattachment to a new chromosome (a one-way event)
unbalanced
72
_________ translocation: two chromosome swap fragments with each other (a two-way event)
reciprocal
73
________ translocation (chromosome fusion): two nonhomologous chromosomes fuse together, with the loss of one of the centromeres
Robertsonian translocation
74
_____________: will move chromosomes I and IV to one poles, and II and III to the other pole
alternate segregation
75
________: will move chromosomes I and III to one pole, and chromosomes II and IV to the other
adjacent segregation
76
________ are associated with many types of cancer, and genomic instabilities
translocations

Genetics 1 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions