B5 Page 3 Flashcards
What do a egg and sperm combine to form? (Fertilised egg)
A zygote.
Where does meiosis happen?
In your reproductive organs.
How many chromosomes do humans have?
A pair of 23 chromosomes (so 46 in total).
How many chromosomes does a zygote have?
46 chromosomes, one set of 23 from each parent.
Meiosis involves how many divisions?
Two divisions.
What does meiosis produce?
Cells which have half the normal number of chromosomes.
What happens before meiosis starts?
The DNA is duplicated.
What happens in the first division of meiosis?
The chromosomes pairs line up in the centre of the cell (vertically).
When the pairs are pulled apart in meiosis what do the new cell have?
Only one copy of each chromosome .
What happens in the second division of meiosis?
The chromosomes line up in the centre vertically. The arms are pulled apart in opposite directions like mitosis.
What is the end product of meiosis?
You get four gametes each with only a single set of chromosomes in it.
What are gametes?
Sperm and an egg separately with 1/2 of the chromosomes.
