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Unformatted text preview: 1 Metabolism Metabolism Metabolism Metabolism s The use of the digested nutrients in chemical processes necessary for cellular activity to sustain life 2 processes: 1. Catabolism = break down of complex compounds to simpler compounds, with the release of ATP 2. Anabolism = build up of simple compounds into more complex substances needed by the cells Cellular Respiration Cellular Respiration s Cellular respiration = the release of ATP from nutrients in a series of chemical reactions s Glucose is the main source of cellular energy s Cellular respiration = oxidization of glucose s glucose + O 2 f CO 2 + H 2 O + ATP s Catalysts are required for all cellular respiration s 2 phases of cellular respiration : 1. Anaerobic phase 2. Aerobic phase Anaerobic Phase/Glycolysis Anaerobic Phase/Glycolysis s The breakdown of glucose in the absence of oxygen s Occurs in the cytoplasm s First step in the of catabolism glucose s Glucose f pyruvic acid (organic) + 2 ATP a lactic acid (during a brief absence of O 2 such as in strenuous exercise) s Rapid but inefficient release of ATP Aerobic Phase Aerobic Phase s The breakdown (catabolism) of glucose in the presence of oxygen s Occurs in the mitochondria s Glucose f pyruvic acid f CO 2 + H 2 O + 34-36 ATP s Takes more time , but very efficient release of ATP Definitions Definitions s Glycogenesis : glucose f glycogen s conversion of excess glucose to glycogen by the liver s Glycogenolysis : glycogen f glucose s release of glucose from the liver into the blood when blood glucose levels become low s Gluconeogenesis : amino acids f glucose s production of glucose from amino acids when the glycogen reserves become exhausted , e.g. in severe carbohydrate restrictive diet, or in starvation 2 Fats and Protein Catabolism Fats and Protein Catabolism s Lipids fatty acids + glycerol s Proteins amino acids s amino acids are used to make ATP only when proteins are overabundant or there is a shortage of glucose & fats s Deamination = removal of ammonia from the amino acid s occurs in the liver s must occur before ATP can be released from protein catabolism s ammonia c urea c eliminated by the kidneys Anabolism Anabolism s Enzymatic chemical reactions combine simple molecules C complex compounds necessary for all cellular material s e.g. enzymes, proteins, cell membranes, tissues s Anabolism is necessary for growth, maintenance, & tissue repair s When anabolism exceeds catabolism net growth occurs s When catabolism exceeds anabolism net loss occurs Fats/Lipids Anabolism Fats/Lipids Anabolism s Fatty acids and glycerol combine f lipids s 2 essential fatty acids (body cannot make them) s can be obtained through a healthy balanced diet 1. Linoleic Acid : s found in sunflower, walnut & sesame oils 2. Alpha Linolenic Acid: s found in flax, walnut oil & wheat germ Protein Anabolism Protein Anabolism s 20 amino acids are needed for protein anabolism s 9 essential s 11 non-essential Essential Amino Acids Essential Amino Acids 1. Histidine 2. Isoleucine2....
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This note was uploaded on 05/04/2008 for the course HP 320 taught by Professor Islam during the Spring '08 term at USC.
- Spring '08