Genetics And Inheritance

Question 1

How are chromosomes characterised

Answer 1

1. Size
2. G band pattern
3. Centromere position (metacentric/ submetacentric/acrocentric)

Question 2

How are some females XY and some males XX

Answer 2

Small region at short arm of Y confers maleness.
XX males have some Y on an X
XY females are missing that Y region

Question 3

Which part of Y confers maleness

Answer 3

SRY encodes protein ghat acts as TDF

Question 4

What’s aneuploidy, % of abortion’s caused

Answer 4

Irregular number of chromosomes

50%

Question 5

Trisomy 21 name, cytogenetics nomenclature, effects

Answer 5

Down syndrome 
47, XX/XY +21
Mental retardation + growth 
Simian crease
Cardiac abnormalities 
Increased incidence of leukemia

Question 6

Trisomy 13 name, nomenclature, abnormalities

Answer 6

Patau s syndrome
47, XX/XY, +13
Heart defects
Incomplete brain development

Question 7

Trisomy 18 name, nomenclature, abnormalities

Answer 7

Edward s syndrome
47, XX/XY, +18
Cardiac defects Intestines protrude out

Question 8

Klinefelter syndrome

Answer 8

XXY
Inferility
Small balls

Question 9

X Turner syndrome

Answer 9

Monosomy
Short stature
Amenorrhea
No growth spurt

Question 10

When’s amniocentesis carried out

Answer 10

Weeks 15-20 of pregnancy

Question 11

Cystic fibrosis

Answer 11

Autosomal recessive
Mutation on chromosome 7-> missing 508th codon -> faulty CFTR-> cl- not pumped out of cell-> no water leaving-> thick mucous layer -> blocked ducts/ infections

Question 12

Huntington’s disease

Answer 12

Autosomal dominant
Neurodegenerative disease
>36 repeats of CAG instead of 28 -> protein aggregation-> cytotoxicity-> cell death

Question 13

Hemophilia A

Answer 13

X linked recessive

Mutation for clotting factor 8