Week 2 Discussion"The Cell, Lokiarcharum, and the Chemicals of Life"This week is all about the some of the smallest parts of life: atoms, molecules, and cells. For your primary post, please respond

 Week 2 Discussion

"The Cell, Lokiarcharum, and the Chemicals of Life"

This week is all about the some of the smallest parts of life: atoms, molecules, and cells. For your primary post, please respond to one of the following two topics and address all questions. Also, reply to at least one fellow student on any topic.

Topic 1 [video]: Introduction to the Cell. Watch the Khan Academy video “Introduction to the cell” (1)* and then address the following issues.

• (a) In the video, the narrator says that we might think that since cells are so small, that they must be simple, but “nothing could be further from the truth.” What did he mean by that?
• (b) Describe features that are only found in eukaryotic (but not prokaryotic) cells.
• (c) Did anything in this video surprise you, or was it mainly a recap of material you already knew?

Topic 2 [article]: Lokiarchaeum. Read about Lokiarcheum in the article by Yong (2)* and/or the article by Zimmer (3)*. Both articles describe recently discovered evidence about a previously unknown organism. Then, address the following questions:

• (a) Lokiarchaeum may be a “transitional form” between archaea and eukarya. What evidence suggests this?
• (b) Describe one way that this relates to this week's lesson.

Topic 3 [video]: Chemicals of Life Video. (added on 1/8/2018) Watch Dr. Cox's video on the "Chemicals of Life" (4)* in the "Instructor Insights" area of Week 2. Then, describe three things you learned from this video.

Note: To get credit for this topic, your post must be based on the video. Answers based on other materials will receive a grade of zero.

References (in Strayer Writing Standards format).

1. Khan Academy, November 29, 2017. Introduction to the cell, https://www.youtube.com/watch?v=5KfHxF6Vhps
2. Ed Yong, May 6, 2015. New Loki microbe is closest relative to all complex life,http://phenomena.nationalgeographic.com/2015/05/06/new-loki-microbe-is-closest-relative-to-all-complex-life/
3. Carl Zimmer, May 6, 2015, Under the sea, a missing link in the evolution of complex cells,http://www.nytimes.com/2015/05/07/science/under-the-sea-a-missing-link-in-the-evolution-of-complex-cells.html?_r=0
4. James Cox, July 12, 2016, The Chemicals of Life (revised). Kaltura video found in Week 2 - Instructor Insights section.

 Week 5 Discussion

"Apoptosis, Crossover, and Tumor-suppressor genes"

This week’s discussion is focused mechanisms that cells use to keep cell division under control, to prevent cancer, and to function well. For your primary post, respond to one of the following three topics. Also, please reply to at least one fellow student on any topic.

Topic 1 [video]: Apoptosis. Watch the Khan Academy video about apoptosis (1)*, then answer the following questions in your own words:

• (a) What is the difference between apoptosis and necrosis?
• (b) What is the role of apoptosis in the normal, healthy development of animals?

Topic 2 [article]: Crossover. Read the article from the University of Rochester on a gene that influences crossover rates in fruit flies. Then address the following: 

• (a)  Explain the relationship between crossover, genetic diversity, and natural selection.
• (b)  Summarize the findings regarding a gene that influences crossover.

Topic 3 [research]: Tumor-suppressor genes versus Proto-oncogenes. This is a library-research topic in which you are required to provide your sources. Mutations in tumor suppressor genes can contribute to or cause cancer, just as mutations in proto-oncogenes can also contribute to or cause cancer. However, tumor suppressor genes are very different from proto-oncogenes.

• (a) Explain why a gain-of-function mutation to a proto-oncogene (or its promoter) may be associated with increased risk of cancer.
• (b) Explain why a loss-of-function mutation to a tumor suppressor gene may be associated with increased risk of cancer.

References:

1. Khan Academy, No date given. Apoptosis [video], https://www.khanacademy.org/science/biology/cellular-molecular-biology/stem-cells-and-cancer/v/apoptosis
2. Lindsey Valich, April 19, 2018. Scientists discover gene controlling genetic recombination rates. http://www.rochester.edu/newscenter/genetic-recombination-selfish-dna-may-help-explain-differences-in-fruit-flies-312422/

 Week 8 Discussion

"Hawaiian Bobtail Squid, Virus Reassortment, and Endophytes"

Many bacteria are helpful, rather than harmful, and some even form partnerships with other organisms. This week you will explore the power of bacteria and viruses. For your primary post, respond to one of the following three topics. Also, please reply to at least one fellow student on any topic.

Topic 1 [video]: The Hawaiian Bobtail Squid and its bacterial endosymbiont. In a 4-minute video clip (1), Bonnie Bassler explains the relationship between the Hawaiian Bobtail squid and it's endosymbiont, the bacterium Vibrio fisheri. Answer the following two questions about this arrangement:

• (a) What are the main characteristics of the partnership between these two species?
• (b) How does each species benefit?

Topic 2 [article]. Virus Reassortment and the Alaska Connection  Read the article from MIT News (2) about tracking the spread of bird flu. Address the following: 

• (a) The article (2) describes genetic reassortment of influenza viruses. Explain how genetic reassortment works and what the significance of it is for humans and for domestic fowl.
• (b) The article (2) explains that one way that influenza strains enters North America is through Alaska. Explain how that works and what the significance of it is for humans and for domestic fowl.

Topic 3 [article]:  Endophytes that benefit plants. Read reference (3) or reference (4) or another article of your choosing about the relationship between plants and their endophytes. .

• (a) Describe what an endophyte is and give a specific example.
• (b) Provide an example of at least one beneficial effect of certain endophytes on their plant hosts. 

References (in Strayer Writing Standards format).

1. iBioEducation, 2013. Quorum sensing in bacteria - Bonnie Bassler, https://www.youtube.com/watch?v=LebqwdQSFHE
2. 2. Anne Trafton, March 17, 2017. Tracking the spread of bird flu, http://news.mit.edu/2017/tracking-spread-bird-flu-alaska-north-america-0317
3. 3. Universidad Politecnica de Madrid, December 18, 2015. Endophytic fungi in elm trees help protect them from Dutch elm disease,  https://www.sciencedaily.com/releases/2015/12/151218085929.htm
4. 4. Claire O'Connell, April 7, 2016. Plants get by with a little help from their microbial friends. https://www.irishtimes.com/news/science/plants-get-by-with-a-little-help-from-their-microbial-friends-1.2593676

 Week 9 Discussion

"Tarnita's Termites, Pacific Lampreys, and Large Brains"

This week our discussion is focused on animal evolution. For your primary post, respond to one of the following three topics. Also, please reply to at least one fellow student on any topic.

Topic 1 [video]: Population Distribution of Termites in a Savanna. Watch the video (1) describing Corina Tarnita's research on the spacing of termite mounds in savanna ecosystems, and then address the following:

• (a) What were Tarnita's findings about the spacing of termite mounds?
• (b) What does Tarnita think is the main factor that governs the spatial distribution of the termite mounds?
• (c) How do the termite mounds benefit other organisms on the savanna?

Topic 2 [video]: Pacific Lampreys. Watch the video about Pacific Lampreys (2)*, then address the following:

• (a) Where do Pacific lampreys fall in the taxonomy of vertebrates?
• (b) What challenges do Pacific lamprey populations face?
• (c) Why are Native American tribes of the Northwest concerned about them? (Please note: take care not to confuse the Pacific lamprey (described in the video) with the Sea Lamprey, which is a completely different species that is considered an invasive species in the Great Lakes).

Topic 3 [article]: Supporting the Energy Needs of a Large Brain. As discussed in the article by Zimmer (3)*, brain tissue is energetically expensive. For a species to evolve a large brain, it may need to make certain adjustments to ensure that enough energy is available to support brain function. Zimmer discusses various hypotheses about such adjustments in the human line of descent. Explain one of these adjustments.

References (in Strayer Writing Standards format).

1. HHMI Biointeractive (2015, November 11). Analyzing patterns in the savanna landscape. [Video]. Retrieved fromhttps://youtu.be/nJGpABrEatc
2. U.S. Fish & Wildlife Service. (2012). Taking the initiative to conserve Pacific Lamprey. [Video]. Retrieved fromhttps://www.youtube.com/watch?v=dkwfDVAoSXk
3. Carl Zimmer, July/August 2011. The brain. Discover, 32 (6), 18-19. https://search.ebscohost.com/login.aspx?direct=true&db=a9h&AN=61992134&site=ehost-live&scope=site [see the note about this link, below]

A note about the above link. The above link, to the article by Carl Zimmer, will only work if you are already logged into EBSCO Host via the Strayer University Library in another browser window. If you don't know how to do that, or otherwise have any trouble using this link, then use the following alternative link zimmer article for week 9 discussion.pdf , which will pull up an text-only version of the article in pdfformat, from Dr. Cox's archives.