What is mitosis?

• The way cells divide to produce more body cells.

Match the following:

____ 1. interphase____ 2. prophase____ 3. metaphase____ 4. anaphase____ 5. telophase

A

E

DC

BE

B

D

C

A

1. Describe the main results of meiosis

Four haploid cells genetically different from each other and from parent cell.

2. What are the principle differences between mitosis and meiosis?

• Mitosis makes body (somatic) cells; meiosis makes gametes (sperm, egg).• Mitosis makes 2 cells, meiosis 4.• Daughter cells from mitosis genetically identical to parent cells; cells from

meiosis different.• Mitosis makes diploid (2N) cells, meiosis haploid (N)

3. What do the terms diploid and haploid mean?

• Diploid = 2 sets of chromosomes.

• Haploid = 1 set of chromosomes.

Human body cells have 23 pairs of homologous chromosomes, or a total of 46.

4. What is crossing over?

• Homologous chromosomes exchange sections of DNA.

tetrad

Chromatid

5. In human cells, 2N = 46. How many chromosomes would you expect to find in a sperm cell? Egg cell? White blood cell? Explain.

• 23• 23 • 46

Connecting Concepts. In asexual reproduction, mitosis occurs, but not meiosis. Which type of reproduction – sexual or asexual – results in offspring with greater genetic variability? Explain your answer.

• Sexual, because offspring get genes from 2 parents.

• In asexual reproduction offspring are genetically identical to parents.

Meiosis video

http://www.youtube.com/watch?v=D1_-mQS_FZ0