Station 5

Cell Cycle

Reporting Category 1

Cell Structure and Function

Bell Ringer - Essential QuestionWhat happens to a eukaryotic cell that does

not complete all stages in the cell cycle?

The cell may enter the GO phase and remain there until the cell reenters the cell cycle. If it passes the GO phase and remains in the cycle, the cell may destroy itself if the DNA has not replicated correctly or the chromosomes fail to separate properly in metaphase. If the cell does not destroy itself, it may become cancerous.

Pre-Review Question

• When a cell divides to make and exact copy of itself it is called…

• A. Meiosis

• B. Bitosis

• C. Mitosis

• D. Taxonomy

Pre-Review Question

• What are the stages of the cell cycle?

• Interphase

• Prophase

• Metaphase

• Anaphase

• Telophase

• Cytokinesis

Pre-Review Questions• What is the longest phase of the cell

cycle?

• Interphase

• Prophase

• Metaphase

• Anaphase

• Telophase

• Cytokinesis

You will now go back to the lab to complete todays activities.

Using the Cycle Characteristics Cards below, determine which section of the Cell Cycle (next slide) each card belongs.

Once you have placed them in the correct order, sketch and name the cycle phases in your journal. Then add the descriptions.

Check your answers.

2. Discuss with your partner:What must happen to a eukaryotic cell before it can go from the G1 phase to the S phase?.

The cell must grow and conduct normal cell activities in preparation for thereplication of the DNA. Certain cell components, such as the centrosomes, duplicate.

3. Discuss with your partner: What happens to a cell in the GO phase?

It may remain in the GO phase and carry out normal functions. It can be stimulated to reenter the cycle if needed or it may be terminated.

4. Discuss with your partner: What happens at the G1/S and the G2/M checkpoints?

• The G1/S checkpoint confirms the presence of all necessary conditions, such as nutrients and enzymes required for DNA replication. If the conditions are not favorable for DNA replication, the cell is arrested in the cycle.

• The G2/M checkpoint confirms that the DNA has been replicated correctly and is ready to go through mitosis and cytokinesis.

5. With your partner, arrange the Phases of Eukaryotic Mitosis and Cytokinesis cards in the order they follow during cell division. Next, remove the Plant and Animal Cell Mitosis and Cytokinesiscards from their envelope and match them to the correct stages.

Use these to help you draw your sketches for question 1.

6. With your partner, look at the Mitosis in an Onion Root Tip sheet. This sheet shows cells in various stages of mitosis. Count the number of cells in each phase of mitosis. Compare your answers with the next slide.

6. Compare your answers

7. Discuss with your partner:Which phase showed the largest number of active cells? Explain why this phase, of all the phases, would most likely have the most abundant number of active cells.

Interphase has the largest number of active cells. Cells in an organism are dividing only when the organism needs to replace damaged cells or when the organism is actively growing. The necessary resources must be available before mitosis can begin again.

9. Discuss with your partner:Cancer can occur in any of the more than 200 types of cells in the human body. During which phase(s) of the cell cycle is a cancer cell most likely to develop?

Cancer cells can occur in any of the phases of the cell cycle – G1, S, or G2.

10. Discuss with your partner:Explain what can happen to a cell that can cause it to become a cancer cell.

There are genes that tell the cell how fast to divide and when to stop. If these genes are mutated, the mutation can cause the cell cycle to go too fast—like running down hill too fast to be able to stop. The cancer cells divide too quickly and pile up in one area— this is called a tumor.

11. Discuss with your partner:What is the relationship between mitosis and growth in an organism?

Mitosis is the process that enables an organism to grow. Growth is the physical increase in size and weight of an organism over a period of time. As cells divide and grow to maturity in G1, they cause the organism to physically grow.

Post-Review Questions

• Name the phase for each cell.

• Prophase

• Interphase

• Anaphase

• Telophase

• Metaphase

A

B

C

D

E

Post-Review Questions• All the following are part of Mitosis

except…

• Interphase

• Prophase

• Metaphase

• Anaphase

• Telophase

Post Review Question

• Cancer cells can occur when cells fail to go into….

• A. G1

• B. G2

• C. G3

• D. G0

• The cell cycle is a continuous process of cell growth and reproduction.

• The cell cycle goes through interphase, the longest phase, before undergoing mitosis and cytokinesis.

• A cancer cell can develop during any part of interphase. A cancer cell is a cell that goes through the cell cycle continuously, never stopping in G0. These cells consume the body’s resources.

• Growth results from mitosis.

• There are checkpoints during the cell cycle to help cells divide correctly.

I need to remember………