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Cytogen > Chromosomal Abnormalities > Flashcards

Chromosomal Abnormalities Flashcards

1
Q

Abnormal chromosomes account for at least____ percent of spontaneous abortions, yet only____ percent of newborns have abnormal chromosomes.

Therefore, most embryos and fetuses with abnormal chromosomes stop developing before birth.

A

50

0.65

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2
Q

When one chromosome is missing

A

Monosomy

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3
Q

Example:
A fruit fly could be lacking a single chromosome, such as chromosome 1, and contain a total of seven chromosomes (2n-1).

This animal is_____ and is described as having____

A

monosomic

monosomy 1.

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4
Q

When one extra chromosome is present

A

Trisomy

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5
Q

Example:
An abnormal fruit fly could have 9 chromosomes instead of 8 because it has three copies of chromosome 2 instead of the usual number of two copies.

Instead of being perfectly diploid (2n), a_______ animal is 2n +1

A

Trisomy

trisomic

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6
Q

The abnormalities in the number of chromosomes.

Changes to the number of chromosomes present.

A

NUMERICAL ABERRATONS

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7
Q

A normal chromosome number which means “good set”

Where an organism has the correct number of complete chromosome sets

A

EUPLOIDY

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8
Q

A cell with “extra sets” of chromosomes.

Occurs when an organism has more than two complete sets of chromosomes.

A

POLYPLOIDY

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9
Q

Very common among flowering plants, including roses, banana, strawberry, cotton, barley, and wheat, and in some insects.

The human liver has tetraploid (4N) and octaploid (8N) cells.

A

Polyploidy

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10
Q

Uneven distribution of chromosomes in meiosis.

A chromosome pair fails to separate at anaphase of either the first or second meiotic division. This produces a sperm or oocyte that has two copies of a particular chromosome, or none, rather than the normal one copy.

A

NONDISJUNCTION

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11
Q

When such a gamete fuses with its partner at fertilization, the zygote has either 45 or 47 chromosomes, instead of the normal 46.

Meiotic error that causes aneuploidy

A

NONDISJUNCTION

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12
Q

Cells missing a single chromosome or having an extra one, which means “not good set”.

Presence of an abnormal number of chromosomes in a cell.

A

ANEUPLOIDY

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13
Q

Occurs when there is an extra chromosome (trisomy) or a missing chromosome (monosomy) within a chromosome pair.

Trisomies are less severe than monosomies

A

ANEUPLOIDY

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14
Q

The meiotic error that causes aneuploidy is called.

A

nondisjunction

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15
Q

______ is common in aneuploidy because development of the brain is so complex and of such long duration that nearly any chromosome-scale disruption affects genes whose protein products affect the brain.

A

Mental retardation

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16
Q

Abnormalities in the number of autosomal chromosomes, which are the non-sex chromosomes.

More severe than Sex Chromosome Aneuploids

A

Autosomal Aneuploids

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17
Q

Down syndrome (trisomy 21) is the most common autosomal aneuploid, followed by trisomies 18 (Edwards syndrome) and trisomy 13 (Patau syndrome)

Most________ are spontaneously aborted. Those that survive have specific syndromes, with symptoms depending upon which chromosomes are missing or extra.

A

Autosomal Aneuploids

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18
Q

People with sex chromosome aneuploidy have extra or missing sex chromosomes.

Sex chromosome aneuploidy usually produces milder symptoms.

A

Sex Chromosome Aneuploids

19
Q

Sex Chromosome Aneuploids

A

Turner syndrome (X)
Triplo X syndrome (XXX)
Klinefelter syndrome (XXY)
XXYY syndrome
XYY syndrome

20
Q

______ have extra sets of chromosomes and do not survive for long.

______have extra or missing chromosomes.______ during meiosis causes aneuploidy.

_______are less severe than monosomies, and _______ aneuploidy is less severe than autosomal aneuploidy.

A

Polyploids

Aneuploids

Nondisjunction

Trisomies

sex chromosome

21
Q

Mitotic nondisjunction produces chromosomal______.

_______ is the most common autosomal aneuploid, followed by trisomies 18 and 13.

Sex chromosome aneuploid conditions include (5) syndromes.

A

mosaics

Down syndrome (trisomy 21)

XO, triplo-X, XXY, XXYY, and XYY

22
Q

Missing, extra, or inverted genetic material within a chromosome or combined or exchanged parts of non-homologs (translocations)

A

STRUCTURAL VARIATIONS

23
Q

normal amount of genetic material persists (inversions and balanced transloca- tions)

A

BALANCED

24
Q

if excess or deficient DNA results (dupli- cations and deletions, which may be caused by inversions or translocations).

A

UNBALANCED

25
Q

one segment of a chromosome becomes attached to a different chromosome or to a different part of the same chromosome.

A

TRANSLOCATION

26
Q

Types of invertion: SURRI

A

Simple Translocaction
Unbalance Translocation
Reciprocal Translocation
Rebertsonian Translocation
Insertional Translocation

27
Q

Single piece of chromosome is attached to another chromosome

A

SIMPLE TRANSLOCATION

28
Q

Two different chromosomes exchange pieces, altering total amount of genetic material is not altered occur without any phenotypic consequences

A

RECIPROCAL TRANSLOCATION (BALANCED TRANSLOCATIONS)

29
Q

Significant portions of genetic material are duplicated and/or deleted.

Generally associated with phenotypic abnormalities or may even be lethal.

A

UNBALANCED TRANSLOCATIONS

30
Q

William Robertson, who first described this type of rearrangement in grasshoppers.

Arises from breaks near the centromeres of two nonhomologous acrocentric chromosomes.

Most common type of translocation that occurs in humans

A

ROBERTSONIAN TRANSLOCATION

31
Q

A rare type of translocation

One chromosome inserts into a nonhomologous chromosome

A

INSERTIONAL TRANSLOCATION

32
Q

Segment of chromosomal material is missing.
Deficient in a significant amount of genetic material.

A

DELETION

33
Q

TYPES OF DELETION
________: chromosome has broken in two places and the broken ends have fused, leaving out the deleted segment.

________: a deletion that occurs towards the end of a chromosome.

A

Interstitial deletion

Terminal Deletion

34
Q

CRI-DU-CHAT
Caused by a deletion in a segment of the_____ arm of human chromosome 5____

mental deficiencies, unique facial anomalies, and, in infancy, an unusual catlike cry,

A

short; (five)

35
Q

A part of the chromosome is present more than once.
Ex. Down syndrome

A

DUPLICATION

36
Q

A position of one chromosome has been deleted from its normal place and inserted into another chromosome.

ex
Chronic Myelogenous Leukemia (CML)

A

INSERTION

37
Q

a rearrangement of chromosome that involves two breaks within a single chromosome

A

INVERTION

38
Q

Types of invertion:
________
An inversion involving only one arm of the chromosome
_________
If the breaks are on opposite sides of the centromere

A

Pericentric inversion

Paracentric inversion

39
Q

A chromosome abnormality when one arm of the chromosome is DUPLICATED and the other is LOST or DELETED

Chromosome divides in a HORIZONTAL/TRANSVERSE pattern

The resultant chromosome are IDENTICAL (ISO-MIRROR IMAGE, SAME

A

ISOCHROMOSOME

40
Q

Most common sex chromosome abnormality in FEMALES

An isochromosome of the long arm, 46,X,i(X)(q10) resulting in the loss of the SHORT ARM

characteristics include SHORT STATURE and INFERTILITY

A

TURNER’S SYNDROME. 46,X,I(XQ)

41
Q

may form when telomeres are LOST, leaving sticky ends that adhere forming a circular or a ring shaped

These problems could include things like learning disabilities, seizures, developmental delays, and other health problems, DEPENDING on which part of the chromosome is affected

A

RING CHROMOSOME

42
Q

EXAMPLES OF RING CHROMOSOME DISORDERS
__________
developmental delay, slow growth and short stature, feeding difficulties, learning difficulties, a small head size, abnormal formation or positioning of the feet and/or toes, and/or abnormalities of the palate

___________
Early onset refractory epilepsy, a seizure disorder, Intellectual disability Autism spectrum disorder, Characteristic facial features. Other health issues, including feeding difficulties

A

Ring chromosomes 13

Ring chromosome 14

43
Q

Types Of abnormality associated with the chromosome number

  • Extra chromosome sets
  • An extra or missing chromosome (“not good set.”)
  • One chromosome absent
  • One chromosome extra
A

Polyploidy

Aneuploidy

Monosomy

Trisomy

Cytogen (34 decks)

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