The Affects of Ph and Pepsin with Proteins

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  • Topic: Acid, PH, Gastric acid
  • Pages : 4 (719 words )
  • Download(s) : 240
  • Published : February 13, 2013
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Background: Pepsinogen is an inactive protein that is the mucus lining of the stomach. When converted to pepsin, the enzyme is used to break down large or undigested protein they has been absorbed by the small intestine. The digestive power of pepsin is greatest at the acidity of normal gastric juice (pH 1.5–2.5). In the intestine the gastric acids are neutralized (pH 7), and pepsin is no longer effective.

"Pepsin (biochemistry)." Encyclopedia Britannica Online. Encyclopedia Britannica, n.d. Web. 10 Dec. 2012.

Research Question: Does changing the pH of pepsin affect the ability to break down the protein (mass of jello).

Variables: independent- Ph level
dependent- The mass of the jello
control- Scale used, concentration of enzyme/substrate, amount of pepsin used in the test tube, same incubator.

Hypothesis: If the Ph level is more acidic then it will break down the protein in the jello when set at body temperature because it will mimic the acid in the stomach that breaks down proteins because the stomach is more acidic than basic.

Materials to complete this experiment use:

Beakers
graduated cylinder
pipettes
distilled water
2% pepsin

Safety considerations:
glasses and gloves while using HCL
ALWAYS WASH HANDS AFTER USUING CHEMICALS.

Method & Procedure:
1. gather all the materials
grab 5 viles and label them 2,4,5,6,8.
take the 2% pepsin and add 2 ml to each vile
take a beaker and add 20 ml of distilled water and 6 drops of HCL to create the pH2, add 1 ml of that solution to the vile labeled 2.

take another beaker and add 20 ml of distilled water and add 3 drops of HCL to create the pH 4.Add 1 ml of that solution to vile 4. to create the pH of 5, add no base or acid, and add 1 ml of distilled water. To created the pH of 6, pour 30 ml of distilled water into a beaker, add one drop of NaOH and add 1 ml of that solution to the vile labeled 6. take another beaker with 60 ml of distilled...
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