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Cell Cycle and Cancer

Investigation 2 – Lab









This Investigation is designed to:

  • teach you that when cells die within a tissue they are replenished through the cell cycle,
  • introduce you to the four phases of the cell cycle (G1, S, G2, and M) and their functions,
  • allow you to build a model representing the cell cycle,
  • assist you in reviewing the stages of mitosis within the M phase of the cell cycle,
  • provide an opportunity for you to review the four stages of mitosis using microscope slides,
  • investigate the consequences of loss of regulation of the cell cycle, and
  • introduce the concept of a mechanism for cell cycle regulation, and allow you to represent regulation in your cell cycle model.


Note: There is no Student Preparation for Investigation 2 Lab.


  • Reflect on the PreLab video as you move through the procedural steps.
  • During the Experiment, every procedural step is important. If one step is skipped, data can become invalid. To help you keep on track, read each step thoroughly, complete the step, then check it off (Read it – Do it – Check it).
  • Complete all of the procedural steps in your SDR.

Note: The procedural steps are listed below for your reference.

Trial 1:

  1. Place the marble in the tubing. The marble represents a cell.
  2. Tape the two ends of the tubing together with packing tape to form a closed ring with the marble inside.
  3. Using a marker, draw 4 lines around the tubing to indicate 4 separate portions of the ring. Look at the diagram for help:
  4. Label each section to represent one phase of the cell cycle in the correct order on the ring: M, G1, S, or G2. Use the diagram in the Background box to help you order the phases correctly.
  5. Draw an arrow on the ring to represent the direction the cycle runs.
  6. Rotate the ring so that the marble moves through each phase of the cell cycle. The location of the marble in the ring represents the phase of the cell cycle that the cell is in.
  1. Use the model to determine what phase of the cell cycle a cell would be in if the cell was replicating (copying) its DNA. 
  1. Use the model to determine what phase of the cell cycle a cell would be in if mitosis is occurring. 

Trial 2:

  1. Set up the microscope according to the Procedure, Microscope Use, and Operation.
  2. Place the onion root tip slide on the microscope stage. Focus first on the lowest power, and then focus using each of the higher power objectives. Finally, view the slide using the oil immersion 100X objective. Refer to the Procedure, Microscope Use, and Operation if necessary.
  3. Look at the different cells within the onion root tip by moving the microscope stage as needed.
  1. Many of the cells in your slide are going through mitosis. Are all of the cells at the same point in mitosis? 
  1. Record: Using the 100 X objective, find four cells that are in different stages of mitosis. Draw each cell in the space provided.


[Phases of Mitosis Drawing]

  1. Can you find cells at all phases of mitosis? Label your drawings with the name of the mitosis phase (prophase, metaphase, anaphase, or telophase) that the cell appears to be in.
  1. What phase of the cell cycle are the cells undergoing mitosis in? 
  1. What phase of the cell cycle might the cells that are NOT going through mitosis be in? 
  1. Is the cell cycle model you made a truly accurate representation of how cells move through the phases of the cell cycle? Why or why not? 

Trial 3:

  1. Alter the cell cycle model to show how the cell stops and starts each phase.

A. Take 4 push pins of the same color. The pins represent the proteins that control the cell cycle.

B. Stick the push pins into the tubing on your model at one of the lines that mark the separation between the phases of the cell cycle.

C. Place the 4 pins evenly around the tube on this line so that there is one on the top, one on the bottom, and one on each side.

D. Test that the marble can not move past the pins.

2. Place each of the other sets of 4 pins on the other lines on your model that mark the transition between the phases.3. Remove, 1, 2, or 3 pins at a time to move the cell (marble) from one phase of the cell cycle to another.




Be sure to clean up your bench after the Investigation.