Chromosomal Alterations: When Meiosis Goes Wrong

Question 1

What is a karyotype?

Answer 1

Representation of the chromosomes from cells of any animal (picture of chromosomes).

Question 2

What happens to a cow’s chromosome structure if they have “Robertsonian Translocation?”

Answer 2

A fusion between 2 chromosomes at the centromere.

Question 3

Explain what happens during a gene deletion or duplication.

Answer 3

Deletion- section of a chromosome is deleted

Duplication- section of a chromosome is repeated over and over

Question 4

What is trisomy and monosomy? Which is more lethal?

Answer 4

Trisomy- extra chromosome

Monosomy- missing a chromosome (more lethal)

Question 5

How often does Down Syndrome occur?

Answer 5

1/800 live births

Question 6

Describe the characteristics of a Down’s individual?

Answer 6

Slanting eyes, single crease on palm of hands, flat nose, respiratory problems.

Question 7

What do genetic councillors do for their clients?

Answer 7

They are able to help their clients analyze the possibility of certain traits. Helping families gain an understanding of family’s genetics and options available to them. Go over a family’s pedigree. Go over risks of genetic diseases.

Question 8

What diseases do people get genetic testing for?

Answer 8

Duchennes, Muscular Dystrophy, Spina Bifida, Cystic Fibrosis.

Question 9

What are some of the risks of amniocentesis?

Answer 9

Miscarriage, leak of amniotic fluid.

Question 10

What shapes are used in a pedigree? What do they stand for?

Answer 10

Circle- female
Square- males
Triangle- unknown

Question 11

What is a karyotype?

Answer 11

The number and visual appearance (size and banding pattern) of the chromosomes in the cell nuclei of an organism.

Question 12

Where is keryotyping performed and what does it produce?

Answer 12

In a laboratory and produces an image of an individual’s chromosomes.

Question 13

What is a karyotype used to look for?

Answer 13

Abnormalities in the number or structure of chromosomes

Question 14

How are karyotype notions wrote?

Answer 14

Number of chromosomes, the specific sex chromosomes, and where possible, the specific extra autosomal chromosome

Question 15

Karyotype notation: Triple X Syndrome
Reason for abnormality:
2-3 symptoms:

Answer 15

47, xxx
Nondisjunction (extra X chromosome)
Learning disabilities, weak muscle tone, abnormally curved pinky fingers

Question 16

Karyotype notation: Klienfelters Syndrome
Reason for abnormality:
2-3 symptoms:

Answer 16

47, xxy
Nondisjunction (extra X chromosome)
Incomplete puberty, weak bones, low energy levels

Question 17

Karyotype notation: Cri du Chat
Reason for abnormality:
2-3 symptoms:

Answer 17

46, xy
Part of chromosome 5 is missing (deletion of genes on chromosome)
Widely spaced eyes, weak muscle tones, low birth weight, mental retardation

Question 18

Karyotype notation: Down Syndrome
Reason for abnormality:
2-3 symptoms:

Answer 18

47, xy + 21
Result of an extra copy of chromosome 21
Respiratory disease, short stature, prone to developing Alzheimer’s

Question 19

Karyotype notation: Williams Syndrome
Reason for abnormality:
2-3 symptoms:

Answer 19

46, xy
The deletion of chromosome 7
Low birth rate, heart defects, low muscle tone

Question 20

Karyotype notation: Turners Syndrome
Reason for abnormality:
2-3 symptoms:

Answer 20

45, X0
Nondisjunction (girls are missing one or part of one of their two X chromosomes)
Failure to grow at expected rate, infertility, chronic ear infections.

Question 21

Karyotype notation: Fragile X
Reason for abnormality:
2-3 symptoms:

Answer 21

46, xy
Duplication of genes on X chromosome
Stuttering, anxiety, attention problems

Question 22

How often are karyotype analysis performed per year in the US?

Answer 22

Over 400 000

Question 23

During mitosis, what happens to the 23 pairs of human chromosomes?

Answer 23

They condense and are visible with a light microscope.

Question 24

What does a karyotype analysis usually involve?

Answer 24

Blocking cells in mitosis and staining the condensed chromosomes with Giemsa dye.

Question 25

What does Giemsa dye do?

Answer 25

Stains regions of chromosomes that are rich in the base pairs Adenine (A) and Thymine (T), producing a dark band.