proposed_essay_questions_2008 - Essay 1 How did Robin...

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Essay 1: How did Robin Warren and Barry Marshall demonstrate the cause of ulcers? The idea that stress causes ulcers was widely accepted until Warren and Marshall proved otherwise. Warren noticed that many of his patients who had stomach problems also had a spiral-shaped bacteria associated with their stomachs. The bacteria are able to survive in the acidic stomach and it makes holes in the stomach wall. Marshall was trying to grow helicobacter pylori and after accidentally letting it sit longer than he should have, he realized he grew the same bacteria that Warren had observed. In order to fulfill Koch’s postulates, Warren and Marshall had to find a host to infect, but they were unable to find an animal model. Marshall then drank the bacteria and caused inflammation in his own stomach. He cured this with antibiotics, thereby proving that bacteria causes ulcers, not stress. Essay 2: How did Walter B. Cannon come up with the concept of “Fight or Flight”? As soon as x-rays were invented, Cannon decided to x-ray the stomachs of uninjured animals. He began to study cats and he noticed that the female cats were calmer in the holder so at first he only x-rayed them. After x-raying a male cat however, he noticed that when the cat was in a rage, his stomach movements stopped. He also noticed that when a female cat was enraged her stomach movements stopped as well leading him to come up with the “flight or fight” response. In other words, when an animal is upset or angry, many physical bodily changes occur to prepare that animal to either fight or run away. The stomach stops moving because the energy is needed in other places. When the animal is calm the movements begin again. Essay 3: How Joseph Goldberger determine that pellagra was due to a vitamin deficiency? Goldberger first did an epidemiological study and found that pellagra was not contagious and
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This note was uploaded on 02/22/2009 for the course BIO 110 taught by Professor Monger during the Fall '07 term at Cornell.

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proposed_essay_questions_2008 - Essay 1 How did Robin...

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