1.4 The Cell Cycle

Cells within the human body have ______life spans. The ______ controls the production (through ______, ______, and ______) of new cells of a variety of different types.

______– periods of ______in the _____ of a cell; consists of ______ growth stages and a stage of ______

______– a ______ in the life of a cell when ______determine whether ______ should or should not occur

Cells “die” when they are damaged due to:

- exposure to ______chemicals or conditions

- ______forces

- the wear and tear of ______use

Cell “suicide” occurs when the cell experiences a “pre-programmed death” due to:

- “suicide” genes code for proteins that ______ the cells in specific situations.

- cell ______ are packaged for use by other cells

______ – an abnormal clump of cells formed when cells divide ______and ______

______– cells with abnormal ______ material that are dividing uncontrollably and can ______ to other parts of the body

Date: Name: Class:
chapter 1 / Section 1.4 Review
(Alternative Format) / BLM 1-14

1.  Why do nerve cells and skin cells have different life spans?

2.  What are two reasons cells leave the cell cycle?

3.  Explain the connection between mitosis and cancer.

chapter 1 / Section 1.4 Review
(Alternative Format) / BLM 1-14
  1. a. How many checkpoints does a cell go through to check its growth before moving on to the next

stage of its cycle?

b. List the checkpoints and the point at which they occur. You may wish to create a simple table to record your answer.

  1. A Yes/No Decision Tree is a flowchart that shows options and pathways. The decision tree below is about cell cycle checkpoints. Complete the missing information in boxes A, B, and C by writing on the lines provided here.

BOX A:

BOX B:

BOX C:

  1. Which of the following places in your body would you find cells that live for a short time?
    Circle your answer. You may circle more than one answer.

a. muscle cells d. brain cells

b. skin cells e. heart muscle cells

c. stomach lining cells

  1. Oh no! You have scraped the skin on your knee. What are the skins cells around the wound doing now? Include information about checkpoints in your answer.
  1. Complete the sentence.

Nerve cells leave the cell cycle and enter a non-dividing stage because ______

______.

  1. a. If you looked at a normal cell and a cancer cell under the microscope, you might not be able to tell

the difference. But behaviourally, the cells are very different. What type of behaviour(s) would you

expect to be different?

b. Is it possible to design a drug that only attacks cancer cells and not normal cells? How might the

drug work?

  1. Some people imagine cancer cells as criminals who have broken the cell’s laws of cell division.
    Fill in the blanks with the crimes the cells commit.

a. Law 1: Most normal cells can undergo ______rounds of cell division. Cancer criminal

cells undergo ______rounds of division.

b. Law 2: Normal cells stop dividing once they reach their specified number of divisions. Some

cancer criminal cells make an enzyme called ______, which signals that they do not have to stop dividing.

c. Law 3: Normal cells produce and recognize suicide-causing ______. Some cancer criminal cells are mutated and do not produce or recognize these.

  1. Considering what you have learned about cancer and about cell cycle checkpoints, would you expect cancer (or a tumour) of the brain to behave any differently than cancer (or a tumour) of the liver? Explain your answer.

______

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