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Digestion Lab. The specific purpose of this lab (activity 4) was to investigate fat digestion by pancreatic lipase and the action of bile, and to recognize whether fat digestion is ongoing or completed (2).

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Introduction

May 13, 2009 Digestive System Activity-4: Assessing Fat Digestion by Pancreatic Lipase and the Action of Bile Objective: The human digestive system is a complex combination of mechanical and chemical processes of digestion. It consists primarily of the gastrointestinal tract, a series of organs and glands that help break down food into smaller molecules for the body to absorb and use for energy. There are six essential activities in the digestion process: ingestion, propulsion, mechanical digestion, chemical digestion, absorption, and defecation. During chemical digestion, enzymes (large protein molecules) and digestive enzymes (hydrolytic) take actions in the catabolic breakdown of food, generally begin in the mouth and conclude within the small intestine. Because digestive enzymes are highly specific and require precise environment conditions for enzyme to function optimally, their hydrolytic activity can also be studied in a test tube. The specific purpose of this lab (activity 4) was to investigate fat digestion by pancreatic lipase and the action of bile, and to recognize whether fat digestion is ongoing or completed (2). ...read more.

Middle

1 2 3 4 5 6 Additives Lipase Vegetable oil Bile salts pH 7.0 buffer Lipase Vegetable oil D.I. water pH 7.0 buffer Lipase D.I. water Bile salts pH 9.0 buffer D.I. water Vegetable oil Bile salts pH 7.0 buffer Lipase Vegetable oil Bile salts pH 2.0 buffer Lipase Vegetable oil Bile salts pH 9.0 buffer Incubation condition 37�C 60 min. 37�C 60 min. 37�C 60 min. 37�C 60 min. 37�C 60 min. 37�C 60 min. pH 6.21 6.72 9.0 7.0 2.0 8.97 The results showed that after 60 minutes of incubation, the pH for test tube 1 decreased from 7.0 to 6.21, the pH for test tube 2 (no bile salts) decreased from 7.0 to 6.72, there were no changes in pH for test tubes 3 (no vegetable oil), 4 (no lipase), and 5, and a slight decreased in pH for test tube 6. Discussion: It was the purpose of this lab to examine fat digestion by pancreatic lipase and the action of bile. ...read more.

Conclusion

Both test tubes have most substances similar, only that test tube 2 has lipase but not bile salts and test tube 4 has bile salts but not lipase. As a result, the pH in test tube 4 does not change, but the pH in test tube 2 decrease, indicating that fat digestion has occurred. Such incidents occur because the optimum pH for lipase activity is pH 7.0. Fat digestion is essential because fat is the most concentrated source of food energy. When you ingest fewer calories than your body needs, your body turns to fat for energy. However, having free fatty acids is not bad because they are necessary to absorb vitamins and a major energy fuel of liver cells and skeletal muscle, which is important for body functioning. Reference: 1. Marieb, E., & Hoehn, K. (2007). Human Anatomy & Physiology (7th ed.), p.884-947. San Francisco: Pearson Education Inc. 2. Zao P., Stabler T., Smith L., Gibson M., Zanetti N., and Lokuta A. (2006). PhysioEx 6.0 for A&P:Laboratory Simulations in Physiology. San Francisco: Pearson Education, Inc. ?? ?? ?? ?? ...read more.

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