Week 2 Discussion The following articles are the basis for this week’s discussion on the Cell, Lokiarchaeum, and rRNA 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-lokimicrobe-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-seaa-missing-link-in-the-evolution-of-complex-cells.html?_r=0 “The Cell, Lokiarcharum, and rRNA” 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 : 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. Week 3 Discussion The following articles are the basis for this week’s discussion on Phytoplankton, Chemosynthesis, and Mitochondria 1 PBS Newshour, March 5, 2014, The phytoplankton that brought Earth to life, 2 JoAnna Klein, July 11, 2018, This snail goes through metamorphosis. Then it never has to eat again. https://www.nytimes.com/2018/07/11/science/snailmetamorphosis.html 3 Cell Press, March 7, 2017, How exercise — interval training in particular — helps your mitochondria stave off old age. https://www.sciencedaily.com/ releases/2017/03/170307155214.htm “Phytoplankton, Chemosynthesis, and Mitochondria” In this week’s discussion you will be exploring energy and how it’s captured, released, and used by all living creatures. For your primary post, respond to one of the following three topics and address all of the questions. Also, please reply to at least one fellow student on any topic. Topic 1 : The phytoplankton that brought Earth to life. Review the video (1)* about the “phytoplankton that brought Earth to life” from the link given below. In this clip, Penny Chisholm discusses a tiny phytoplankton called Prochlorococcus. Based on that video, address the following: • (a) What is the importance of Prochlorococcus for life on the planet Earth today? • (b) In the video, Dr. Chisholm tells us that Prochlorococcus samples from different environments that are genetically different. What does this tell us about the relationship between organisms and their environments? • (c) Share how this relates to this week’s lessons. Topic 2 [article]: Snails that don’t eat. A recent article by JoAnna Klein (2)* describes a partnership between the snail Gigantopelta chessoia and a chemosynthetic bacterium. The bacterium is called an “endosymbiont” because it lives inside the snail. • (a) Describe the partnership between Gigantopelta chessoia and its endosymbiont. • (b) What is most surprising to you about this situation? • (c) Explain how this relates to this week’s lessons. Topic 3 [article]: Exercise and mitochondria. Exercise is generally known to have many beneficial effects on our bodies at several different levels. Some studies have examined the effects of exercise at the level of muscle cells. Read the press release by Cell Press (3)*. • (a) What specifically did these researchers measure in their volunteers? • (b) What were their findings? • (c) Explain how this relates to this week’s lessons.