5-Chromosomal_Abnormalities_Flashcards

Question 1

How many chromosomes do humans typically have?

Answer 1

46 chromosomes (23 pairs).

Question 2

What are the two types of chromosomes in humans?

Answer 2

Autosomes (22 pairs) and sex chromosomes (1 pair: XX or XY).

Question 3

What are chromosomal abnormalities?

Answer 3

Errors in the number or structure of chromosomes leading to health problems.

Question 4

What are some effects of chromosomal abnormalities?

Answer 4

Miscarriages, stillbirths, malformations, intellectual disabilities, and identifiable syndromes.

Question 5

What are the two main categories of chromosomal abnormalities?

Answer 5

Numerical and structural disorders.

Question 6

What is aneuploidy?

Answer 6

A deviation from the normal diploid number of chromosomes.

Question 7

Give an example of aneuploidy.

Answer 7

Trisomy (2n+1) or monosomy (2n-1).

Question 8

What is polyploidy?

Answer 8

A change involving multiples of the haploid set of chromosomes (e.g., triploidy, tetraploidy).

Question 9

What is a deletion?

Answer 9

Loss of a chromosome segment.

Question 10

What is a translocation?

Answer 10

Exchange of segments between chromosomes.

Question 11

What is an inversion?

Answer 11

Reversal of a chromosome segment.

Question 12

What is a ring chromosome?

Answer 12

A chromosome forms a circular structure due to end fusion.

Question 13

What are the two types of cell division where errors can occur?

Answer 13

Mitosis and meiosis.

Question 14

What is nondisjunction?

Answer 14

Failure of chromosomes to separate properly during cell division.

Question 15

What is mosaicism?

Answer 15

Presence of two or more cell populations with different genotypes from one zygote.

Question 16

What causes Down syndrome (Trisomy 21)?

Answer 16

An extra copy of chromosome 21.

Question 17

What are some characteristics of Down syndrome?

Answer 17

Intellectual disability, distinct facial features, and heart defects.

Question 18

What causes Patau syndrome (Trisomy 13)?

Answer 18

An extra copy of chromosome 13.

Question 19

What is the prognosis for Patau syndrome?

Answer 19

Most affected individuals die within the first year of life.

Question 20

What causes Edwards syndrome (Trisomy 18)?

Answer 20

An extra copy of chromosome 18.

Question 21

What is the prognosis for Edwards syndrome?

Answer 21

Most affected individuals die within the first year of life.

Question 22

What causes Turner syndrome (XO)?

Answer 22

Missing one X chromosome in females (45, XO).

Question 23

What are some features of Turner syndrome?

Answer 23

Short stature, webbed neck, and infertility.

Question 24

What causes Klinefelter syndrome (XXY)?

Answer 24

An extra X chromosome in males (47, XXY).

Question 25

What are characteristics of Klinefelter syndrome?

Answer 25

Infertility, reduced body hair, and learning difficulties.

Question 26

What is Triple X syndrome (XXX)?

Answer 26

Females with an extra X chromosome (47, XXX).

Question 27

What is Double Y syndrome (XYY)?

Answer 27

Males with an extra Y chromosome (47, XYY).

Question 28

What is Cri-du-chat syndrome?

Answer 28

Deletion on the short arm of chromosome 5.

Question 29

What causes DiGeorge syndrome?

Answer 29

Microdeletion on chromosome 22q11.2.

Question 30

What is Angelman syndrome?

Answer 30

Deletion on chromosome 15 inherited from the mother.

Question 31

What is Prader-Willi syndrome?

Answer 31

Deletion on chromosome 15 inherited from the father.

Question 32

What is a Robertsonian translocation?

Answer 32

Fusion of long arms of two acrocentric chromosomes.

Question 33

What is cytogenetics?

Answer 33

Study of chromosomes, their structure, and inheritance.

Question 34

What is karyotyping?

Answer 34

Visual representation of chromosomes arranged in pairs.

Question 35

What does G-banding in karyotyping do?

Answer 35

Produces characteristic banding patterns for chromosome identification.

Question 36

What is FISH (Fluorescence In Situ Hybridization)?

Answer 36

A technique to detect specific DNA sequences using fluorescent probes.

Question 37

What is spectral karyotyping (SKY)?

Answer 37

Assigns a different color to each chromosome for visualization.

Question 38

What is array-CGH?

Answer 38

High-resolution technique to detect DNA gains or losses.

Question 39

How is a normal female karyotype written?

Answer 39

46, XX.

Question 40

How is Down syndrome written in karyotype notation?

Answer 40

47, XY, +21.

Question 41

What does 'del' indicate in karyotype nomenclature?

Answer 41

Deletion.

Question 42

What does 't' indicate in karyotype nomenclature?

Answer 42

Translocation.

Question 43

What disorders can cytogenetic testing diagnose?

Answer 43

Down syndrome, Turner syndrome, and Cri-du-chat syndrome.

Question 44

What is the role of cytogenetics in genetic counseling?

Answer 44

Provides families with information on chromosomal abnormality risks.

Question 45

How is prenatal screening performed?

Answer 45

Through amniocentesis or chorionic villus sampling.

Question 46

What are euchromatin and heterochromatin?

Answer 46

Euchromatin is transcriptionally active; heterochromatin is condensed and inactive.

Question 47

What are Barr bodies?

Answer 47

Inactivated X chromosomes in females.

Question 48

What does XCI stand for?

Answer 48

X-chromosome inactivation.

Question 49

What is the typical size of the human genome?

Answer 49

3.2 billion base pairs.

Question 50

What is the ISCN?

Answer 50

International System for Human Cytogenetic Nomenclature.