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Metabolism: Transformations and Interactions I. Chemical Reactions in the Body Plants use the sun’s energy to make carbohydrate from carbon dioxide and water. This is called photosynthesis. Humans and animals eat the plants and use the carbohydrate as fuel for their bodies. During digestion, the energy-yielding nutrients are broken down to monosaccharides, fatty acids, glycerol, and amino acids. After absorption, enzymes and coenzymes can build more complex compounds. In metabolism they are broken down further into energy (ATP), water and carbon dioxide. A. Metabolic reactions take place inside of cells, especially liver cells. B. Anabolism is the building up of body compounds and requires energy. C.…show more content…
c. Protein provides 4 kcal/gram. d. Fat provides more energy because the bonds in fat molecules are easily oxidized and result in more ATP. III. Energy Balance When energy intake exceeds energy output, there is a gain in weight. Excess energy can come from protein, fat or carbohydrate. Fat is the most efficient in being stored as fat. A. Feasting—Excess Energy 1. Excess protein is converted to fat but this is inefficient and indirect. Its priority is other roles. 2. Excess carbohydrate is converted to fat but this is inefficient and indirect. Its priority is glycogen stores. 3. Excess fat is efficiently converted to fat. B. The transition from feasting to fasting draws on reserves. C. Fasting—Inadequate Energy 1. Glucose Needed for the Brain 2. Protein Meets Glucose Needs 3. The Shift to Ketosis- produced when glucose is not available a. Ketosis causes a suppression of the appetite. b5. Slowing of Metabolism 6. Symptoms of Starvation a. Muscle wasting b. Decreased heart rate, respiratory rate, metabolic rate, and body temperature c. Impaired vision d. Organ failure e. Decreased immunity f. Depression, anxiety, and food-related dreams 1. Define metabolism, anabolism, and catabolism; give an example of each. 2. Name one of the body’s high-energy molecules, and describe how is it
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