Meiosis (lecture)

Question 1

What are the 5 chromosomes that can translocate and still yield a viable fetus?

Answer 1

13, 14, 15, 21, 22

Question 2

What does dark band staining of a chromosome indicate (2 things)?

Answer 2

Gene poor; CG rich

Question 3

What does light band staining of a chromosome indicate (2 things)?

Answer 3

Gene rich; AT rich

“Genes are AT the light bands”

Question 4

Draw out meiosis steps, including the point at which crossing over takes place…

Answer 4

https://en.wikipedia.org/wiki/Meiosis

Question 5

What protein complex is responsible for pairing in meiosis?

Answer 5

Synaptonemal

Question 6

How does gene location on a chromosome influence the chance of it crossing over?

Answer 6

Chances of crossover are greatest in the medial regions.

Question 7

What is translocation?

Answer 7

Crossing over between non homologous chromosomes?

Question 8

What is the difference between balanced and unbalanced translocations and their implications?

Answer 8

• Balanced: no genetic material is lost - no problem

- Unbalanced: genetic material is lost - big problem

Question 9

At what point in meiosis is egg development arrested during embryogenisis? What hormone stimulates its progression to meiosis 2?

Answer 9

Meiosis 1 prior to metaphase, LH surge in menstrual cycle initiates ovulation and progression of meiosis to meiosis 2

Question 10

What stimulates oocyte meiosis progression to complete meiosis 2?

Answer 10

Fertilization

Question 11

What is the source of organelles of the fetus?

Answer 11

Maternal gametes, sperm do not provide the organelles

Question 12

Why do older females have a higher incidence of abnormal kids?

Answer 12

Age related impairment of chromosomal segregation during meiosis
Age related spindle formation issues

Question 13

What is the most common form of aneuploidy?

Answer 13

T 21 - Down

Question 14

Baby born to 40 y.o. mother and has clubbed feet index finger crossed over middle? What is the prognosis?

Answer 14

Trisomy 18

15% die w/in 1 week, 90% die w/in one year (CV and Pulmonary)

Question 15

Baby born to 45 y.o. mother and has polydactyly, rocker feet and middle cleft lip?

Answer 15

Trisomy 13

Question 16

Kid with wide set eyes (Trojan warrior), developmental delay, and middle cleft lip - genetic cause and syndrome name?

Answer 16

4p deletion - Wolf-Hirshhorn syndrome

Question 17

Kid with round face and cat-like cry - genetic cause and syndrome name?

Answer 17

5p deletion - Cri du chat (French for cat meow)

Question 18

Very friendly kid with pale blue eyes and sub aortic stenosis - genetic cause and syndrome name?

Answer 18

7q deletion - Williams

Question 19

Kid with mental development delay and jerky movement - genetic cause and syndrome name?

Answer 19

15q11 del - angelman

Question 20

New born with loss of sucking reflex, almond eyes, strabismus, and poor muscle tone - genetics and syndrome?

Answer 20

15q11 del - Prader Willi

Question 21

Kid with long history of infection, hypocalcemia, metrology of Fallot, cleft pallet - genetics and syndrome?

Answer 21

CATCH - 22: CVD, Abnormal facies, Thymic aplasia, Cleft palate, and hypothyroid/hypoparathyroid
del 22 - DiGeorge

Question 22

Kid with behavioral problems, flat bridge of the nose, square face, and prominent jaw - genes and syndrome?

Answer 22

Del 17q11 - Smith Magenis

Question 23

What lab technique is commonly used to detect deletions of genes?

Answer 23

Microassay

Question 24

15 y.o. male presents with delayed puberty, small testes, is tall and uncoordinated - genetic and name of syndrome?

Answer 24

47, XXY - Kleinfelter

Question 25

Girl with broad, webbed neck, short and cardio abnormalities - genetics and name of syndrome?

Answer 25

45, X - Turner