Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CMD Block 2 > Chromosome Number > Flashcards

Chromosome Number Flashcards

1
Q

Why does Trisomy 21 occur more frequently in young mothers?

A

Young mothers have more babies than older mothers– even though the risk is smaller DS has a higher prevalence in this age group

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

What form of chromosomes are targeted in a slide preparation for FISH?

A

Metaphase or interphase

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

Test that applies a specific probe in order to determine the number of copies of chromosome present

A

FISH

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

How does a fluorescent probe join DNA?

A

DNA is denatured and hybridized with complementary probe

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

FISH analysis can determine…

A

if the probed chromosomes are numerically correct

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

FISH analysis cannot determine…

A

if anything is wrong with unprobed regions of the genome nor if mosaicism is present

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

Mitotic nondisjunction creates presence of more than one cell line

A

Mosaicism

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

Mosaicism

A

Mitotic nondisjunction creates presence of more than one cell line

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

What is the most plausible cause of trisomy mosaicism?

A

Normal cell line at conception, then a nondisjunction event gave rise to an additional chromosome

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

Always results from post-zygotic error

A

mosaicism

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

Possible locations of mosaicism

A

Generalized, confined to placenta, confined to fetus

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

What limits diagnosis of mosaicism?

A

Limitations in sampling, which includes tissue specific differences

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

Level of mosaicism correlates with

A

phenotypic severity

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

Which tissues often contain trisomic cells?

A

Kidney, placenta, gut

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

Nondisjunction

A

error in cell division in which improper segregation results in abn chromosome number

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

Error in this leads to mosaicism

A

mitosis

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

Which portion of cell division has an age-related risk of maternal nondisjunction?

A

Meiosis I

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

How many normal daughter cells result for meiosis I nondisjunction?

A

0

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

How many normal daughter cells result for meiosis II nondisjunction?

A

2

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

Euploid

A

normal chromosome number

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

Aneuploidy

A

abnormal chromosome number

22
Q

Polyploidy

A

Additional set of chromosomes

23
Q

Most common cause of triploidy

24
Q

Cause of tetraploidy

A

Failure of cell division

25
T/F: ALL monosomies are lethal
T
26
Trisomies than can result in a live birth
13. 18, 21, Sex chromosomes
27
How does mosaicism affect the severity of a trisomy?
The normal chromosomes make the phenotype less severe
28
Including preimplantation errors, how many fertilized eggs spontaneously abort?
50%
29
Common sex chromosome abnormality, frequently results in spontaneous ab
45, X
30
Why do monosonies reflect such a small portion of observed spontaneous abortions?
They abort so early detection is uncommon.
31
Why does the risk of a trisomy 21 offspring decrease as the pregnancy develops?
Spontaneous abortions
32
Phenotypic result of 47,XXX 47,XXY or 47XYY
Pretty minor problems with a normal lifespan
33
Common phenotypic characteristics of Down Syndrome
heart defects, simian crease, MR, duodenal atresia (obstruction)
34
Most common cause of trisomy 21?
Meiosis I nondisjunction
35
Trisomy 21 mosaicism is (more/less) severe than a purely trisomic genome
Less
36
Common phenotypic characteristics of trisomy 18
Clutched hands, rocker bottom feet, MR, heart defect
37
Common phenotypic characteristics of trisomy 13
Midline defects (cleft palate, eyes close-set or fused), forebrain fails to form lobes, MR, abdominal defects, polydactyly
38
Common causes of trisomy 13
Maternal meiosis nondisjunction > Robertsonian
39
Why are extra copies of X tolerated?
All but one is inactivated
40
Common phenotypic characteristics of Turner Syndrome
Ovarian dysgenesis, amenorrhea, infertility, abn lymphatics, no MR, neck webbing
41
Result of X chromosome nullisomy
Non-viable
42
Only tolerated monosomic condition
45,X (still has a high rate of miscarriage)
43
Most likely cause of Turner's Syndrome.
Paternal meiotic nondisjunction (no relation to advanced maternal age)
44
What may contribute to the high survival rate of Turner's Syndrome genotype?
Mosaicism
45
Possible genotypes of mosaic Turner's Syndrome
45,x/47,XXX or 45,X/46,XX or 45,X/46,XY
46
Genotype of Klinefelter's Syndrome
47,XXY
47
Common causes of Klinefelter's Syndrome
50% Paternal nondisjunction, 50% age-related maternal nondisjunction
48
Common phenotypes in Klinefelter's Syndrome
hypogonadism, long extremities, reduced IQ, gynecomastia
49
Most common cause of Triple X Syndrome
Maternal nondisjunction, related to age
50
Phenotypic results of Triple X Syndrome
essentially normal
51
Cause of 47,XXY Syndrome
Paternal meiosis II nondisjunction without age effect

CMD Block 2 (38 decks)

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