Unit 4 --Bellwork #3

• 1. Explain at least two ways in which mitosis and meiosis are different.

• 2. Why do sperm and egg have only 23 chromosomes?

• 3. The haploid number of a species is 22. What is its diploid number?

• 4. What are gametes?• 5. In meiosis, the final result in females is

one _______ and three ____________.

Cell division controls, cancer and chromosome number

Notes

Cell division controls

• Cells grown in lab will grow across petri dish until they touch another cell or the edges

• Cyclin is a protein that regulates cell growth

• Other proteins control the steps of cell cycle thus control growth

How cancer relates to mitosis• Cancer is the uncontrolled

division of cells• Cancerous cells do not respond to

normal growth controls, grow until all food is gone

• Thought to be caused by changes in genes controlling mitosis

• Form masses of tissues called tumors

• Can be caused by smoking, pollution, radiation, some viruses and some are inherited

Compare diploid and haploid number

• Diploid: cell that contains two of each kind of chromosome (2N)

• Body cells are diploid• Body cells are called Somatic

Cells • Haploid: cell with only one kind

of chromosome (N) • Gametes (sex cells) are haploid

Unit 4 – Quiz #31. What is the uncontrolled growth of cells called? a. cancer b. cyclin c. mutation2. If cells stop growing when the touch other cells

they are ______ cells. a. cancerous b. mutated c. normal3. Body cells contain 2N number of chromosomes.

They are ? a. diploid b. haploid4. Sex cells contain N number of chromosomes.

They are ? a. diploid b. haploid5. A plant has 40 chromosomes in the body cells.

How many would be in the sex cells? a. 20 b. 40 c. 80

Part 2 Quiz – Next Class• Mitosis: identify pictures of each phase,

explain what is happening, name cell cycle steps in correct order (IPMATC)

• Meiosis: explain what happens, what you end up with, diploid/haploid

• Cancer: what happens in the cell

• SA#1: Differences between Meiosis & Mitosis (chart to fill in)

• SA#2: Causes of cancer