proposed_essay_questions - Bio G 110 Prelim I Spring 2007...

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Bio G 110 Prelim I Spring 2007 Two of the following essays will appear on the First Prelim. Essay 1: How did Robin Warren and Barry Marshall demonstrate the cause of ulcers? Until recently, gastric ulcers were thought to be caused by stress or spicy food. However, Robin Warren noticed that many of his patients with stomach problems had a spiral-shaped bacteria associated with the epithelium of the stomach. The bacteria was acid tolerant, and produced chemicals that put holes in the wall of the stomach. Barry Marshall tried to culture spiral shaped Helicobacter pylori with out success until he accidentally left it out over Easter. When he returned he found colonies of the same bacteria that Warren had described. They weren’t done however, they had to fulfill Koch’s 3 rd postulate so Marshall drank a culture of Helicobacter pylori and induced an ulcer in himself. The conclusion is that 80% of ulcers are caused by the helicobacter pylori and stress induced ulcers account for only 20% of ulcers. Essay 2: How did Walter B. Cannon come up with the concept of “Fight or Flight”? Cannon was studying the movement of the digestive system of cats with the newly invented x-ray machine. Stomach movement was only seen in docile female cats and not in the male cats. He decided to only use the female cats to continue his experiment. When the docile cat’s kittens were threatened the movement in the stomach stopped but when he stroked the cat the stomach began moving again. His ultimate conclusion was that strong emotions influenced the digestive tract and that our mind and body were of one working system. This led cannon to propose the “fight or “flight” (also four F’s) in which the body changes from its state of “rest and digest” to a more active pattern. Essay 3: How Joseph Goldberger determine that pellagra was due to a vitamin deficiency? Goldberger hypothesized through the observation of orphans and prisoners that pellagra was not caused by an infectious agent but was most likely caused by a poor diet. He also assumed it wasn’t contagious because the nurses and attendants did not catch it. He assumed the diets of the nurses and attendants had better diets
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This test prep was uploaded on 09/24/2007 for the course BIO G 110 taught by Professor Wayne,r. during the Spring '07 term at Cornell University (Engineering School).

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proposed_essay_questions - Bio G 110 Prelim I Spring 2007...

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