Chromosomal Abnormalities

Question 1

karotype meaning?

Answer 1

collection of someone’s chromosomes

Question 2

steps to prepare karotype?

Answer 2

1. collect venous blood
2. isolate white cells
3. culture in presence of phytohaemagglutinin
4. after 48 hours add colchicine
5. place in hypotonic saline
6. place on slide
7. fix and slide

Question 3

type of staining which leaves banding pattern?

Answer 3

Giesma staining

Question 4

structure of chromosome?

Answer 4

p-arm (short)
q-arm (long arm)
several bands across both arms

Question 5

3p22

Answer 5

short arm of 3rd chromosome
22 refer to the exact banding position

Question 6

what to bands represent?

Answer 6

different compaction i.e.
dark (heterochromatin) more compact so fewer genes

light (euchromatin) more open so more genes

Question 7

another method of staining karotype?

Answer 7

fluorescent staining

Question 8

whole genome sequencing?

Answer 8

has become a lot cheaper and quicker since first done
plan is to make this available for those with cancer
already available for children with suspected abnormality

Question 9

aneuploidy meaning?

Answer 9

abnormal number of chromosomes

Question 10

purpose of meiosis?

Answer 10

reduction from diploid to haploid
ensures genetic variation of the gametes
ensures random assortment and recombination

Question 11

non-disjunction?

Answer 11

uneven number of chromosomes in daughter cells
meiosis I - all daughter cells affected
meiosis II - half affected
results in +1/-1 chromosome