Cytogenetics

Question 1

Chromosome ideogram

Answer 1

Method of displaying chromosomes
Chromosomes are banded using stain
Changes in band sizes can show insertions or deletions

Question 2

Fluorescence In Situ Hybridization (FISH)

Answer 2

Chromosome painting
DNA hybridized to probe: each probe specific to one particular chromosome
Makes it easier to distinguish chromosomes than with earlier methods

Question 3

Karyogram

Answer 3

Picture of chromosomes lined up according to number

Question 4

How many strands of DNA per chromosome?

Answer 4

Each chromosome has 2 sister chromatids
Each chromatid has 1 molecule of DNA
2 strands per molecule
4 strands total

Question 5

Metacentric chromosome

Answer 5

Short arm (p) and long arm (q) are of equal size

Question 6

Submetacentric chromosome

Answer 6

Long arm (q) is longer than short arm (p)

Question 7

Acrocentric chromosome

Answer 7

Long arm (q) is much longer than short arm (p)
Short arm (p) is very short

Question 8

Centromere

Answer 8

Middle “pinching” part of chromosome

Junction of long (q) and short (p) arms

Question 9

Telomere

Answer 9

Ends of chromosomes
Organize chromosomes in the nucleus
Protection of chromosome by formation of end cap
Allow chromosome to be replicated completely

Question 10

Aneuploidy

Answer 10

Loss or gain of whole chromosomes

Question 11

Down syndrome

Answer 11

Trisomy 21 (3 of chromosome 21)
Caused by overdosage of chromosome 21 genes

Question 12

Cri du Chat syndrome

Answer 12

Deletion of chromosome 5p

Causes intellectual disability, weak cat-like cry, language delay, low muscle tone