Bio Lab 6 - Google Docs PDF

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Each question is worth 0.5 points unless otherwise noted. I. Cell Cycle and Cancer Click and Learn Procedure: Navigate to The Eukaryotic Cell Cycle and Cancer https://media.hhmi.org/biointeractive/click/cellcycle/ and answer the questions below as you work through the activity. Click on the “Background” tab on the right side. Read the information and watch the videos. 1. Why is cell division important for both single-celled and multicellular organisms? For single-celled organisms, cell division is the only way they can reproduce. For multicellular organisms, cell division is how they grow and replace dead/damaged cells. 2. Why does cell division remain important to an adult organism even after it is fully developed? Cell division is important to an adult organism even after it is fully developed because cells have to divide to heal wounds, cells have to divide to renew cells in our skin a gut etc. 3. Cells divide, differentiate, or die. What is differentiation? Cell differentiation is when a cell stops dividing to and goes on to specialize in structure and function. For example, a striated muscle tissue are groups of differentiated cells that all serve one purpose of structure and function. 4. What is apoptosis? What is its purpose? Apoptosis is programmed cell death. Apoptosis eliminates cells that are damaged, cancerous etc, to maintain homeostasis at a cellular level 5. What are cell cycle regulators? Cell cycle regulators are proteins that control the progression through the cell cycle. They can inhibit progression and stimulate it. 6. What happens if cell cycle regulators don’t function properly? If cell cycle regulators don’t function properly, we can end up with too few, or too many cells. Too few cells, for example, can lead to hair loss. For too many cells, you can end up with cancer, tumors etc. Click on the purple section labeled “Cell Cycle Phases” as well as the words “Mitosis” and “Interphase” to read an overview of the cell cycle. You can also click on the various phases. 7. The rest of the cell cycle is called interphase, during which (use the blank below to complete the sentence) The rest of the cell cycle is called interphase which includes phases G1, S, and G2. During interphase, cells grow and replicate DNA 8. Fill in the details about what happens during the three phases of interphase labeled in the diagram. During the G1 phase, cells entering this phase have just completed mitosis(cell division). In this phase the cells get bigger in size, and prepare to duplicate DNA. During the S phase, this is where these cells replicate DNA. This means by the end there are now two sets of chromosomes. During the final phase within interphase, G2, the cells keep growing and now prepare to divide.

9. In general, what is the purpose of a checkpoint in the cell cycle? The purpose of a checkpoint in the cell cycle is to basically make sure that the process, whether it be DNA replication, or cell growth etc, are complete.

10. What is the G0 phase of the cell cycle? The G0 phase of a cell is a “resting phase.” In this phase the cell sin’t dividing or preparing to divide. 11. Which factors determine whether a cell enters G0? The cell goes into the G0 phase when resources are insufficient, or they received a signal to go there. 12. Can cells leave G0? Yes, cells can leave the G0 phase if they aren’t fully differentiated, and if the body needs to grow or has been injured and needs to heal.

Click on “Cell Cycle Regulators and Cancer” in the center purple circle. Read the “Regulators Overview” and then read through the “Cancer Overview” and watch the videos. 13. What are cell cycle regulators? Cell cycle regulators are proteins that control the progression through the cell cycle. They can inhibit progression and stimulate it.

14. Stimulating proteins are encoded by Stimulating proteins are encoded by proto-oncogenes.

15. Examples include: Examples of a stimulating protein are: CDK-cyclin, APC/C. 16. Inhibitory proteins are encoded by Inhibitory proteins are encoded by tumor suppressor genes.

17. Examples include: Examples of an inhibitory protein are: p53 protein, Retinoblastoma protein(Rb).

18. Cancer is the result of an improperly regulated cell cycle. Describe two reasons why cells can form tumors. Cells can from tumors from too much, and too little cell division. 19. In some types of colon cancer, stem cells have a mutation in the APC gene. What happens if the APC gene is mutated?

If the APC gene is mutated, you have a higher probability of developing gastrointestinal polyps, colorectal cancer, and maybe other cancers as well. 20. Normally, proto-oncogenes stimulate the cell cycle. What are oncogenes and how do they affect the cell cycle? Oncogenes are mutated versions of porto-oncogenes. Oncogenes contribute to the development of cancer. They stimulate cell division of “bad’(mutated) cells. 21. To cause cancer, proto-oncogenes require (a)_________ allele(s) to be mutated and therefore are considered (b)_________ . The mutation results in a (c)________ of function. a.One b.Dominant c.Gain

22. Normally, tumor suppressor genes inhibit the cell cycle. How do mutated tumor suppressor genes affect the cell cycle? Mutated tumor suppressor genes affect the cell cycle by resulting in a loss of function.

23. To cause cancer, tumor suppressor genes require (a)__________ allele(s) to be mutated and therefore are considered (b)_________. The mutation results in a (c)________ of function. a. Both b. Recessive c. Loss

II. Mitosis and Meiosis Virtual Lab 24. DNA replication and cell growth occur during DNA replication and cell growth occur during interphase. 25. Cell division occurs during Cell division occurs during mitosis(M phase). 26. How many cells are in each phase in the image below Interphase

x

Prophase

xx

Metaphase/Anaphase Telophase/ Cytokinesis

xxxx x

27. Calculate the time for each stage (count only cells marked with X) and fill in the table below. A key for identification is shown below. Sibling cells = cytokinesis. (4 points)

% of cells in the stage × 1440 minutes = number of minutes in the stage

phase

cells

Time spent in each phase per 1440 minutes

Interphase

11

11/38 x 1440=417

Prophase

3

3/38 x 1440=114

1

1/38 x 1440=38

Anaphase

1

1/38 x 1440=38

Telophase/ Cytokinesis

3

3/38 x 1440=114

Total number of cells

19

19/38 x 1440=720

Metaphase

28. Because you do not have access to a microscope, we have provided you with a larger data set shown below. Number of Cells Field 1

Field 2

Total

Interphase

71

101

172

73.2%

1054.0

Prophase

13

15

28

12.0%

171.6

Metaphase

12

13

25

10.6%

153.2

Anaphase

1

2

3

1.3%

18.4

Telophase

3

4

7

3.0%

42.9

Total Cells Counted

235

Use the provided table to create an appropriate graph using google sheets (https://docs.google.com/spreadsheets/u/0/). Instructions for creating a graph can be found here: https://support.google.com/docs/answer/63824?co=GENIE.Platform%3DDesktop&hl=en Parameters: Title: Timing of the cell cycle Y Axis: Time in minutes X Axis. Phase Insert your graph below. (4 points)

29. List three major differences between the events of mitosis and meiosis. 1. Mitosis creates body cells while meiosis creates sex cells 2. In mitosis, daughter cells are identical, but in meiosis, daughter cells are genetically different 3. Mitosis has one cell division while meiosis has two cell divisions

30. In a fungus, Sordaria, why are crossover events visible? Crossover events are visible in the fungus Sordaria because of the pattern colored spores(ascospores) shows how many are crossing over.

31. Insert screenshots of your answers to the “Comparison of Mitosis and Meiosis” activity below. Please crop out irrelevant info.

32. Insert a screenshot of your complete lab Quiz II below. Please crop out irrelevant info.

Post Lab Questions (2 points each) 1. What key events would signal that a cell is going through meiosis, rather than mitosis? If the ploidy of the cell changed after division then the cell has undergone meiosis rather than mitosis.

2. A scientist tells you that he has found a cool single-celled organism that is about to divide. He tells you that the homologous chromosomes are not paired and that it doesn't look like any recombination has occurred. Is the organism dividing by mitosis or meiosis? Explain. The organism is dividing by mitosis. This is because homologous chromosomes pair in meiosis. If there is no pairing, then the cell isn’t dividing in meiosis.

3. A scientist tells you that he has a cell with 46 chromatids. He asks you if the cell is diploid or haploid. What is the answer? Does your answer change if he tells you that the original cell had 23 chromatids? What has happened to the cell? The cell could be either haploid or diploid. We don’t know if the chromatids are separate or paired, so we can’t tell if the cell is haploid or diploid. 4. Describe the three phases that makeup interphase. How are they alike? Different? Interphase is made up of the G1, S, and G2 phases. In the G1 phase, newly formed cells mature. If the cell is going to divide, it moves into the S phase(synthesis phase). In this phase DNA gets replicated. The G2 phase is where more growing occurs. They are different in the sense that they all have different duties, but similar in that they all have the same goal of getting the cell to the M phase....