Chromosomes to Bases Flashcards
how many chromosomes does a normal human have?
46
what does 46 XX mean?
female
what does 46 XY mean?
male
how can chromosomes be recognised?
banding patterns
length
position of the centromere
describe the overall structure of a chromosome
telomeres at either end
short arm (p) and long arm (q)
centromere between the arms
what is an acrocentric chromosome?
one where the short arm is so small it is negligible
what are the two types of chromosome rearrangements?
balance
unbalanced
what is a balanced chromosome rearrangement?
all chromosomal material is present
what is an unbalanced chromosome rearrangement?
extra or missing chromosomal material
what is aneuploidy?
a whole extra or missing chromosome
what is translocation?
rearrangement or chromosomes
what are insertions and deletions?
missing or duplicated material
what is 47 XY + 21?
Down syndrome
what is a robertsonian translocation?
when two acrocentric chromosomes are stuck end to end
what chromosomes can be affected by robertsonian translocation?
14
21