meiosis

Question 1

describe the steps of meiosis

Answer 1

1. the DNA is replicated
2. the pairs of chromosomes line up along the centre of the cell
3. the pairs are pulled apart
4. two new cells are formed, each with one copy of each chromosomes, from each parent cell
5. in each of the cells, the chromosomes line up along the centre again
6. the arms of the chromosomes are pulled apart
7. four gametes are formed which contain half the number of chromosomes

Question 2

what happens at fertilisation?

Answer 2

-gametes join to restore the normal number of chromosomes
-the new cell divides by mitosis
-the number of cells increases
-as the embryo develops cells differentiate

Question 3

what do meiosis and fertilisation do with the number of chromosomes?

Answer 3

meiosis halves the number, and fertilisation restores the number

Question 4

why are the daughter cells genetically different?

Answer 4

they all have different chromosomes