Bio 241 Hmwrk 1

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Christopher Scott
Biol 241 homework
Professor: Greg Crowther

1. Compare and contrast the reasons cell division is important for unicellular and multicellular organisms. Cell division is the method in which single celled organisms reproduce. Cell division allows multi-cellular to grow and repair dead or damaged cells

2. Provide an example of why cell division remains important to an adult organism even after it isfully developed. Some cells divide to heal wounds such as cuts or broken bones.

3. What is the role of growth factors? Growth factors send molecular signals that tell cells to divide.

4. Cells divide, differentiate, or die. What is differentiation? Differentiation is when a cell stops dividing to perform a special function
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a. ______Neuron cell__________________________________________
b. ______Liver cell_________________________________________

23. Cancer is the result of an improperly regulated cell cycle. Name two reasons why cells can form tumors. A mutation can cause cells to become unable to differentiate and subsequently pile up. Damage to tumor suppressing genes can cause tumors to form. Oncogenic mutations can cause excessive cell division causing the formation of tumors.

24. What causes uncontrolled cell division at the genetic level? A mutation in just one allele of proto-oncogenes can cause over production of cells tumor, and thus tumor formation, because they are dominant. Tumor suppressor genes require mutations of both alleles to inhibit function because they are recessive.

25. Watch the video clip. At the cellular level in this example, explain what occurs if the APC gene is mutated. When the APC gene mutates it cannot differentiate and the gene starts to pile up. 26. Normally, proto-oncogenes stimulate the cell cycle. What do mutated proto-oncogenes (i.e., oncogenes) cause? Oncogenes cause overproduction of cells.

27. Normally, tumor suppressor genes inhibit the cell cycle. What do mutated tumor suppressor genes cause? Mutated tumor suppressor genes lose their ability to suppress tumors.

28. To cause cancer, proto-oncogenes require 1 (circle one)
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