Eukaryotic Cell Cycle and Cancer Worksheet PDF

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cheese is not cheese when the cheese is too cheesy to be cheese so the cheese bust have less cheese to be considered cheese...

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The Eukaryotic Cell Cycle and Cancer In Depth

Click & Learn Student Worksheet

INTRODUCTION This handout complements the Click & Learn The Eukaryotic Cell Cycle and Cancer and is intended as an indepth examination of the cell cycle and the protein players involved. For a more general overview, please see the overview version. PROCEDURE Follow the instructions as you proceed through the Click & Learn and answer the questions in the spaces below. Click on the “Background” tab on the right side. 1. Compare and contrast the reasons cell division is important for unicellular (single-celled) and multicellular organisms.

Single cells reproduce this way and multi cells does it to replace old cells and heal so it can function 2. Provide an example of why cell division remains important to an adult organism even after it is fully developed.

It is needed to help organisms heal wounds and stuff, needs to still be able to heal when injured and stuff 3. What is the role of growth factors?

give signals to cells to split, otherwise cells would never divide.

4. Cells divide, differentiate, or die. What is differentiation?

Differentation is when a cell stops dividing in order to specialize in a particular function

5. What is apoptosis? Explain its purpose.

Apoptosis is used to eliminate unecessary, damaged, or unhealthy cells through what is in essence a programmed death for the cell 6. Organisms maintain the right number of cells by regulating the cell cycle. What are “cell cycle regulators?”

They function as molecular signals to initiate cell death, prompt or cease cell division, or direct cells to undergo differentiation 7. Watch the video clip of cells in the small intestine. Name the general location along the villus where the following processes occur: Cell Division: bottom of the crypt Cell Differentiation: on the way ot the lumen Apoptosis:top of villus Cell Cycle www.Bi www.BioInte oInte oInteractive ractive ractive.org .org

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The Euka ry otic Cel ryo elll Cycle a nd Ca ncer – In Dep eptth 8. Name one harmless result of too little cell division.

hair loss 9. Name one harmless result of too much cell division.

warts Click on the section of the circle labeled “Cell Cycle Phases” in the center purple circle on the right and use the “Overview” information in the window on the left to answer the questions below. 10. List, in order, the four events we collectively call the “cell cycle.” Next to each event, write the correlating cell cycle phase name. a.

G1: the cell comes out of mitosis and grows in size as it prepares to replicate DNA, makes sure its healthy enough to do so.

b. S: In this phase, the DNA is replicated and is constantly checked for any errors or mutuation in replication c. G2: The cell matures as it grows and prepares itself for the cell division phase d. Cell division: cell splits into two and cell cycle finishes 11. In general, what is the purpose of a checkpoint in the cell cycle?

A check point in the cell cycle acts as a point that regulates progression from one stage of the cycle to the next without any errors in the cell or in its DNA 12. What is one potential outcome when errors occur in this highly regulated cell cycle process?

development of cancer Click on “Cell Cycle Regulators and Cancer” in the center purple circle on the right. Use the information under “Regulators Overview” in the window on the left to answer the questions below. 13. What type of protein that regulates the cell cycle is encoded by proto-oncogenes?

encode proteins that keep cell cylce progression going 14. What type of protein that regulates the cell cycle is encoded by tumor suppressor genes?

tumor suppressor genes encode proteins that halt the cell cycle Cyclin dependent Kinases 15. The most important cell cycle regulators are the ______________________________________ . 16. What is a kinase, and what does it do?

A kinase is an enzyme that adds phosphate to another molecule

17. When are CDKs present inside the cell during the cell cycle?

CDKs are always in the cell, but they are active only after being bound to a cyclin protein 18. When are cyclins present inside the cell during the cell cycle?

The concentration of individual cyclins fluctuates and they are only present at certain stages of the cell cycle Cell Cycle www.Bi www.BioInte oInte oInteractive ractive ractive.org .org

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The Euka ry otic Cel ryo elll Cycle a nd Ca ncer – In Dep eptth 19. CDKs form molecular complexes with cyclins. What do activated CDK-cyclin complexes do?

Activated CDK-cyclin protein complexes control the speed at which the cell cycle takes place Using the cell cycle diagram on the right and both links in the center purple circle, complete the table below for each phase. Use bullet points and focus on major events that occur during each phase, checkpoint, and regulatory process. Complete the entire row before moving on to the next phase. PHASE

PHASE EVENTS

Cell increase in size G1

prepares to replicate DNA

CHECKPOINT EVENTS

REGULATORY PROCESSES

confirm no damage is present on DNA Confirm resources available to continue

Replicate DNA

Confirm there are no issues in replicated DNA

continued cell growth to prep for division

COnfirm DNA is intact and confirm theres 2 sets of chromosomes confimr there are proper amounts of components for 2 full cells

stop growing

COnfirm that sister chromatids attach to the mitotic spindle

S

G2

M (mitosis)

divide into 2 full cells

20. Go to “Cell Cycle Phases” and click on “Interphase.” The interphase alternates with mitosis. What happens during interphase and what phases does it include?

21. Go to “Cell Cycle Phases” and click on “G0.” The G0 phase is a resting or nondividing stage. What three factors determine if a cell enters G0?

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22. Provide an example of a fully differentiated cell that is (a) permanently in G0 and (b) one that can leave G0 to progress through the cell cycle and divide again. a. b. Click on “Cell Cycle Regulators and Cancer” in the center purple circle on the right. Then click on the “Cancer Overview” tab in the window to the left (right tab). 23. Cancer is an improperly regulated cell cycle. Name two reasons why cells can form tumors.

24. What causes uncontrolled cell division at the genetic level?

25. Watch the video clip. At the cellular level in this example, explain what occurs if the APC gene is mutated.

26. Normally, proto-oncogenes stimulate the cell cycle. What do mutated proto-oncogenes (i.e., oncogenes) cause?

27. Normally, tumor suppressor genes inhibit the cell cycle. What do mutated tumor suppressor genes cause?

28. To cause cancer, proto-oncogenes require ___ 1 (or) ___ 2 allele(s) to be mutated and are therefore considered ___ dominant (or) ___ recessive. This results in a ___________ of function. 29. To cause cancer, tumor suppressor genes require ___ 1 (or) ___ 2 allele(s) to be mutated and are therefore considered ___ dominant (or) ___ recessive. This results in a ___________ of function. 30. Watch the video clip. a. Using the gas pedal analogy, explain the impact on the cell cycle of a proto-oncogene versus an oncogene.

b. Using the brake pedal analogy, explain the impact on the cell cycle of one mutated tumor suppressor gene allele versus two mutated tumor suppressor alleles.

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ADVANCED EXTENSION QUESTIONS (OPTIONAL) Now that you have finished the Click & Learn, use your knowledge to answer the following questions. 31. p53 is a protein that is encoded by a tumor suppressor gene, and some scientists refer to it as “the guardian of the genome.” a. Explain its normal role and why scientists would regard it as the “guardian of the genome.”

b. Explain what happens to the cell cycle if both alleles of the gene encoding p53 are mutated.

32. Explain why people who inherit one mutated allele of the BRCA1 gene have a higher likelihood of developing cancer.

33. Predict a potential outcome of a mutated mitotic arrest deficient (MAD) protein.

34. Use the model illustrated in the figure below to answer the accompanying questions.

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a. The human gene EGFR located on chromosome 7 is a proto-oncogene that codes for a growth factor cell surface receptor. The binding of growth factors to this receptor can lead to cell proliferation. Hypothesize what potential impact a mutated EGFR allele will have on a cell. Give one possible impact and explain your answer.

b. RAS is a G protein that is activated when a growth factor attaches to EGFR. Its activation results in the exchange of GTP for GDP. Once activated, the GTP cannot be hydrolyzed and RAS cannot be deactivated What is one potential outcome of a mutation in one of the two copies of RAS?

c. Mutations in the genes that code for proteins in this pathway have been linked to various types of cancer (i.e., RAS: pancreatic, BRAF: colorectal, MEK: melanoma, EGFR: lung). If you were developing a new cancer drug, what would be an appropriate target protein for the new drug therapy? Justify your answer.

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