HUN1201 Exam III Study Guide Chapter 7 Metabolism Define o Metabolism the sum of all chemical and physical processes by which the body breaks down and builds up molecules calorimeter o Anabolism the process of making larger chemically complex molecules from smaller ones growth repair maintenance synthesis of chemical products essential for human functioning REQUIRES ENERGY o Catabolism the breakdown of larger complex molecules to smaller more basic ones starts with digestion chemical reactions break down proteins lipids carbs old cells tissues catabolized for repair replacement RELEASES ENERGY o Condensation anabolic process in which simple units combine to form a larger more complex molecule and WATER IS RELEASED as a by product o Hydrolysis catabolic process in which a large molecule is broken apart with the ADDITION OF WATER o Oxidation Oxygen removes an electron from a molecule molecule LOSES E oxidized becomes more positive o Reduction molecule GAINS E becomes more negatively charged charge is REDUCED o Phosphorylation the addition of a phosphate group to a compound occurs when the high energy phosphate bonds in ATP are broken energy is released and phosphate is transferred to other molecules Phosphorylation of glucose glucose oxidized loses an e for energy or stored as glycogen o Enzymes chemical reaction mediators speed up reactions o Coenzymes non protein substances i e vitamins FAD FADH2 necessary to bind compound to enzyme for reaction to occur o Cofactors non organic substances necessary for enzyme activity i e minerals iron Mg Zn What is ATP o ATP Adenosine Triphosphate organic compound used by cells as a source of energy potential energy stored in HIGH ENERGY PHOSPHATE BONDS released when bonds broken used to keep cells functioning o Found in mitochondria primary site of production Metabolic pathways clusters of chemical reactions that occur sequentially to achieve a particular goal occur in specific parts of cells specific organs tissues networking of metabolic pathways none occur in isolation Glucose oxidation in the liver glucose can be phosphorylated metabolized for energy or stored as glycogen in muscles can be released into circulation for other cells to use as energy or store as glycogen or be converted to fatty acids if glucose exceeds energy needs be stored as triglycerides in fat tissue o Other monosaccharides converted to glucose in liver follow same process Metabolic pathways involved in Glucose Oxidation 1 Glycolysis occurs in CYTOSOL cytoplasm of cells ANAEROBIC REACTION 1 glucose molecule uses 2 ATP 4 ADP and 2 NAD to produce 2 ADP 4 ATP 2 NADH H 2 pyruvate NET PRODUCTS 2 ATP 2 NADH H Gluconeogenesis resynthesis of glucose from pyruvate when not needed for immediate cell energy reverse pathway of glycolysis In absence of O2 ANAEROBIC conversion of PYRUVATE from glycolysis to LACTATE lactic acid in muscle cells cytoplasm uses 1 NADH H to produce 1 NAD reduction of NADH H to produce NAD for the ctnd Production of pyruvate via glycolysis o lactate converted back to pyruvate and then glucose in the liver transported back into bloodstream to be used for energy or travel back to muscle where cycle starts again In presence of O2 Transition step in glucose oxidation AEROBIC process occurs in the MITOCHONDRIA of cells 2 pyruvate consume 2 NAD and 2 CoA to produce 2 Acetyl CoA and release 2 NADH H and 2 CO2 NO REVERSE PATHWAY TO GENERATE PYRUVATE FROM ACETYL COA Metabolic crossroads Glucose converted to pyruvate via glycolysis or glucoenic amino acids converted to pyruvate pyruvate used to generate acetyl CoA via transition step in presence of oxygen or generated from ketogenic amino acids fatty acids or alcohol 2 TCA Tricarboxylic Acid Cycle AEROBIC process occurs in MITOCHONDRIA of cells series of 8 metabolic reactions 2 acetyl CoA metabolized to produce 4 CO2 2 high energy GDP ATP and reduced coenzymes NADH FADH2 uses up NAD and FAD Acetyl CoA not regenerated in TCA cycle 2 CoA released and 2 C form CO2 but oxaloacetate generated in last step of TCA cycle reused in 1st step 3 Oxidative Phosphorylation Electron transport chain AEROBIC process occurs in INNER MEMBRANE OF MITOCHONDRIA series of metabolic reactions that transports electrons from NADH or FADH2 through a series of carriers in oxidation reactions process generates ATP H2O LIPOLYSIS dietary adipose triglycerides broken down into glycerol backbone 3 fatty acids by enzyme lipase Glycerol converted to pyruvate then to acetyl CoA or glucose via gluconeogenesis to enter TCA cycle Fatty acids released directly into bloodstream to be used by cells for energy attach to ALBUMIN and transported to working cells muscle liver that need energy activated by COENZYME A then shuttled across mitochondrial membrane into cell by CARNITINE What is beta oxidation FATTY ACIDS metabolism process by which long chain fatty acids are broken down into 2 C segments to form ACETYL COA which then enters TCA cycle passed down e transport chain to generate ATP ANAEROBIC process 2 C segment cleaved off in each stage in which 1 FAD and 1 NAD is reduced to produce 1 FADH2 and 1 NADH H and 2 Acetyl CoA are produced leaving a shorter chain fatty acid o Products of Acetyl CoA produces ATP in TCA cycle FADH2 and NADH H produces ATP in electron transport chain produced in complete beta oxidation rxn of C originally in chain 2 What is ketone how is it synthesized KETONES by products of fat catabolism KETOSIS when acidic ketones inappropriately lower blood pH KETOACIDOSIS when blood pH falls resulting in severe dehydration BAD when diet insufficient in carbohydrates not enough glucose for TCA cycle to occur because cannot produce enough oxaloacetate ACETYL COA forms ketone bodies acetoacetate which produce Acetone beta hydroxybutyrate PROTEOLYSIS dietary proteins digested catabolized into amino acids smaller peptides which are transported to the LIVER where they are used for protein synthesis or released into blood for uptake by other cells for building repair functions EXCESS dietary protein stored as triglycerides fat in adipose tissue or used for energy after glucose glycogen fatty acid stores depleted ENERGY FROM PROTEIN C skeleton of amino acids converted to pyruvate which is converted to acetyl CoA which enters TCA cycle etc Deamination of amino acids liver produce keto acids NH3 ammonia ammonia used as N source for synthesis of nonessential amino acid Toxic at high levels liver converts ammonia to less toxic urea using CO2 excreted
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