Campbell41 - Nutrition and Digestion All living organisms need to acquire and use energy Two ways life obtains energy Autotrophs:Producers Convert

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Nutrition and Digestion All living organisms need to acquire and use energy Two ways life obtains energy: Autotrophs :Producers; Convert sunlight energy into chemical bond energy Heterotrophs : Harvest energy from chemical bond energy in plant and animal tissue Food is taken in, taken apart, and taken up in the process of animal nutrition In general, animals fall into three categories: Herbivores eat mainly autotrophs (plants and algae) Carnivores eat other animals Omnivores regularly consume animals as well as plants or algal matter What is provided by food? Chemical Energy (ATP) for metabolism Organic building blocks Essential nutrients that I cannot make o Essential amino acids o Essential fatty acids o Vitamins Proteins Made up of combinations of 20 different amino acids. Proteins are the major structural component that makes up all cells and are used to build up muscle tissue Proteins also include all of the enzymes, antibodies, and most hormones of the body. Proteins are used as an energy source only if carbohydrates and fats are limiting. Essential amino acids (8/20): we cannot make; must include in diet. Non-essential amino acids : We can synthesize Complete proteins : Contain all essential amino acids in proper ratio Incomplete proteins: lacks one or more essential amino acids Meat and dairy products offer the highest amounts of complete proteins Vegetarians and vegans need to monitor and possibly use supplements Importance of fats for metabolism 1. Needs fats for cell membranes and nervous system function. 2. Fats serve as insulation to conserve body heat and provide cushion to vital organs. 3. Fat stores > 90% of our energy reserves and provides up to 70% of our energy
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during rest. a. One gram of fat has > 2X energy compared to one gram of carb or protein 4. Fat is a major source of energy during exercise 5. Cholesterol is used to make all steroid hormones 6. Fat-soluble vitamins (A,K,E) rely on fat for transport and storage 7. Hunger suppressor: Slow digestion and absorption from GI tract Types of fats Simple Lipids Triacylglycerols: Three fatty acids attached to glycerol backbone Saturated and unsaturated fatty acids Essential fatty acids: Omega-3 and Omega-6 fatty acids Essential fatty acids are those that cannot be made by the body and need to be included in our diet. Omega-3 fatty acids Unsaturated fatty acid in which 1 st double bond is found in the third carbon of the hydrocarbon chain. Names of common omega-3 fatty acids alpha linolenic acid ( ALA ) and two derivatives EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) Main dietary sources of omega-3 fatty acids: Fish (cold-water) and some vegetable sources (nuts,oils). Fish high in omega-3 fatty acids include salmon,sardines, mackerel and tuna
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This note was uploaded on 07/07/2010 for the course BIOLOGY bild 2 taught by Professor Schroeder during the Spring '09 term at UCSD.

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Campbell41 - Nutrition and Digestion All living organisms need to acquire and use energy Two ways life obtains energy Autotrophs:Producers Convert

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