MONDAY DO NOW Assign Yourself – Cell Cycle/Cell Differentiation Biorganizer – Cornell Notes page 38 Title: Cell Cycle DO NOW: Copy this image on to page 38

The Cell Cycle and Cancer

ANNOUNCEMENTS Biology IA #1 will October 7th Tutorials start Thursday at 7am right here in the best classroom in the school…Mrs. Powell’s Biology Class.

What are the 4 phases of the Cell Cycle? G1 (growth 1) = cell grows bigger S = DNA replication; cell copies its DNA G2 (growth 2) = cell grows bigger M = mitosis; cell divides G1 + S + G2 = “interphase”

INTERPHASE G1 Phase (Growth 1) Cell Grows Bigger

INTERPHASE S Phase DNA Replication

Processing Piece #1 Why do you think the first thing the cell does is to grow during Cell Division?

INTERPHASE G2 Phase (Growth 2) Cell Grows Bigger

Mitosis Mitosis and Cellular Division

What are internal regulatory signals? Signals from inside the cell Control many things, including the cell cycle

What causes cancer? When a cell loses the ability to respond to internal regulatory signals, it can keep growing and dividing. This happens because of mutations in the DNA. A cell that cannot stop dividing becomes a cancerous tumor.

Processing Piece #2: Scientists trying to find ways to treat cancer often try to stop a certain part of the cell cycle. Which part do you think they try to stop (G1, S, G2, or M) and why? Challenge question: Can you think of any harmful side effects that this might cause?

How do we treat cancer? Cancer treatments usually target cells that are undergoing mitosis. (They try to either kill the cells or just stop them from dividing.) This also hurts normal cells that are dividing, like hair cells and digestive tract cells.

Exit Ticket All in complete sentences! What causes cancer? What are some of the side effects of cancer treatments? What are the 4 phases of the cell cycle? Which phase is most commonly targeted by cancer treatment? Why does the cell need to grow twice during the cell cycle?

Cell Differentiation

(Don’t write this.) How many different types of cells do you think can be found in your body?

(Don’t write this.) How many different types of cells do you think can be found in your body? About 400!!

(Don’t write this.) But if mitosis produces identical cells… how do you end up with 400 different kinds of cells?

What is a gene? A piece of DNA that contains the instructions for a single type of protein.

What does it mean to “express” a gene? Using the DNA in that gene to make a protein. What does it mean to “repress” a gene? NOT using the DNA in that gene to make a protein.

Processing Piece #1: Write “express a gene” and “repress a gene” and draw a picture to help yourself remember both. (Example: You could draw a stop sign for repress, and a go sign for express.)

What is differentiation? What is a stem cell? A cell that can change to become any type of cell (bone cell, muscle cell, etc.) What is differentiation? When a stem cell becomes a specialized cell (like a blood cell) by expressing certain genes and repressing others.

How does a zygote become an adult? What is a zygote? A single cell (made from a sperm and an egg) that becomes an entire adult. How does a zygote become an adult? Mitosis (the zygote produces a lot of stem cells) Differentiation (stem cells become specialized cells) Growth (specialized cells multiply)

Processing Piece #2: Draw a picture to illustrate each of the 3 steps (mitosis, differentiation, growth). Label the zygote, the stem cells, the specialized cells (bone, muscle, etc.), and the adult.

Exit Ticket True of false: A stem cell differentiates by expressing some genes and repressing other genes. What are the 3 steps that need to happen (in order) for a zygote to become an adult?