Chromosomes Flashcards
Where is DNA found?
On chromosomes in the nucleus of eukaryotic cells
How does DNA fit in?
It has to be wound up into chromosomes
How many genes do each human chromosomes contain?
Between a couple of hundred and a few thousand
How many homologous pairs of chromosomes do humans have?
23 (46 in total), e.g two number 1s, two number 2s etc.
Where do the chromosomes come from in each pair?
One from each pair comes from your mother and one from your father
What do both chromosomes in a pair have in common?
They are the same size and carry the same genes (which is why they’re called homologous pairs)
What do the chromosomes in a pair have that’s different?
Different alleles (different versions of the genes)
What is an X - shaped chromosome?
One chromosome attached to an identical copy of itself
When are chromosomes X - shaped?
Only just after the DNA has been replicated ( e.g in cell division)
What is each side of the X referred to as and what is the bit in the middle when they’re attached to it called?
A chromatid, when attached to it the bit in the middle is called the centromere
