Cell Division - Meiosis Flashcards
What happens in sexual reproduction (meiosis)
Two cells called gametes combine to for, a new individual
How many copies of each chromosomes do gametes have
They only have one copy of each chromosomes
Why do gametes only have one copy of each chromosome
So that you can combine one sex cell from the mother and one sex cell from the father and still end up with the right number of chromosomes in body cells
How many chromosomes in human body cell
46 chromosomes
Why do gametes only have 23 chromosomes
So that when an egg and sperm combine you get 46 chromosomes again
What will happen to the new individual cell
It will have a mixture of two sets of chromosomes, this means that it will inherit features from both parents
What does meiosis involve
Two divisions
Where does meiosis only happen
In the reproductive organs
What does meiosis produce
It produces cells which have half the normal number of chromosomes
How many chromosomes do gametes have
They have half the number of chromosomes
What is the first part of the process of meiosis
It duplicates it’s DNA, one arm of each chromosomes is an exact copy of other
What happens in the first division of meiosis
The chromosome pairs line up in the centre of the cell
What happens after the first division in meiosis
The pairs are pulled apart, so each new cell only has one copy of each chromosome.
Why are the pairs pulled apart (after first division)
So that some of the fathers chromosomes and some of the mothers chromosomes go into each new cell
What happens in the second division
The chromosomes line up again in the centre of the cell then the arms of the chromosomes are pulled apart
