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33 Cards in this Set
- Front
- Back
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metabolism
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-all of the reactions in the body that require energy transfer -2 kinds: Anabolism and Catabolism |
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anabolism
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-requires input of energy to synthesize larger molecules
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catabolism
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-releases energy by breaking down large molecules into smaller molecules
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Catabolism drives anabolism
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-catabolic reactions that break down glucose, fatty acids, and amino acids serve as energy sources for the anabolism of ATP
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aerobic cellular respiration
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-complete catabolism of glucose requires oxygen as final electron receptor -breaking down glucose req many ensymaticly catalized steps- first are anaerobic |
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glycolysis
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-conversion of glucose into two molecules of pyruvic acid
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glycogenesis
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-production of glycogen mostly in skeletal muscles and liver
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glycogenolysis
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-hydrolysis breakdown of glycogen =glucose 6 phosphate for glycolysis(in liver only) or free glucose secreted in blood |
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gluconeogenesis
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-production of glucose from noncarb molecules incl lactic acid and amino acids primarily in liver
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aerobic respiration of glucose
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3 steps 1.Glycolysis-occurs in cytoplasm;anaerobic 2.Citric Acid cycle(Krebs)-occurs in matrix of mitochondria;aerobic 3.electron transport-occurs on cristae of mitochondria inner membrane;aerobic C6H12O6 + O2 >6 CO2 + 6 H2O + ATP |
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glycolysis
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-first step in catabolism of glucose occurs in cytoplasm of cell -glucose splits into 2 pyruvic acid molecules |
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glycolysis formula
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-6-carbon sugar >2 molecules of 3-carbon pyruvic acid -C6H12O6>2 molecules C3H4O3 -Note loss of 4 hydrogen ions. These were used to reduce 2 molecules of NAD. 2NAD + 4H+ > 2NADH + H+ (2NADH) |
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glycolysis
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-Glucose + 2 NAD + 2 ADP + 2 Pi> 2 pyruvic acid + 2 NADH + 2 ATP - pyruvic acid will be used in a metabolic pathway called the citric acid cycle, and the NADH will be oxidized to make ATP. |
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Lactic Acid
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-When there is no oxygen to complete the breakdown of glucose, NADH has to give its electrons to pyruvic acid -results in the reformation of NAD and the conversion of pyruvic acid to lactic acid -anaerobic metabolism/lactic fermentation |
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Lactic Acid Pathway
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-Yields a net gain of 2 ATP - Muscle cells can survive for awhile without oxygen by using lactic acid fermentation. -RBCs can only use lactic acid fermentation because they lack mitochondria |
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Citric Acid Cycle
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-TCA -Acetyl CoA combines with oxaloacetic acid to form citric acid -Citric acid starts the citric acid cycle and ‘moves’ through a series of reactions to produce oxaloacetic acid again |
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process of citric acid cycle
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-One guanosine triphosphate (GTP) is produced, which donates a phosphate group to ADP to form ATP -Three molecules NAD are reduced to NADH.-One molecule FAD is reduced to FADH2 -These events occur for each acetic acid, so it happens twice for each glucose molecule |
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For each glucose TCA
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For each glucose: -6 NADH -2 FADH2 -2 ATP -4 CO2 |
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Electron transport and oxidative phosphoration
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-In the folds or cristae of the mitochondria are molecules that serve as electron transporters. -Include FMN, coenzyme Q, and several cytochromes -accept electrons from NADH and FADH2. - hydrogens are not transported with the electrons. -Oxidized FAD and NAD are reused |
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electron transport chain
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-Electron transport molecules pass electrons down a chain, with each being reduced and then oxidized. -exergonic reaction, and the energy produced is used to make ATP from ADP -ADP is phosphorylated= oxidative phosphorylation. -Process is not 100%; difference is released as heat |
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oxidative phosphorylation
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1.Electron transport fuels proton pumps, pump H+ from the mitochondrial matrix to space between inner& outer membranes 2.sets up huge conc gradient betw membranes 3.H+ can only move thru inner membrane thru respiratory assemblies 4.Movement of H+ across membrane provides energy to enzyme ATP synthase converts ADP to ATP |
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oxygen
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-Final electron acceptor - citric acid cycle and electron transport require it to continue -Water is formed in the following reaction: O2 + 4 e- + 4 H+ >2 H2O |
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ATP
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-Direct (substrate-level) phosphorylation in glycolysis and the citric acid cycle yields 4 ATP. -Oxidative phosphorylation in electron transport yields varying amounts of ATP, depending on the cell and conditions. |
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ATP yields
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-each NADH yields 3 ATP and each FADH2 yields 2 ATP; actual yield is 2.5 ATP per NADH and 1.5 ATP per FADH2 -36-38 per glucose, actual is 30-32 ATP per glucose; energy is needed to move ATP from mitochondria to cytoplasm |
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glycogenesis
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-Cells can’t store much glucose because it will pull water into the cell via osmosis. -Glucose is stored as a larger molecule called glycogen in the liver, skeletal muscles, and cardiac muscles. -Glycogen is formed from glucose via glycogenesis |
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glycogenolysis
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-When the cell needs glucose, it breaks glycogen down again. -Produces glucose 1-phosphate -Glycogen phosphorylase is the catalyst |
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glycongenolysis
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-Glucose from glycogen is form glucose 1-phosphate, so cannot leave muscle or heart cells. -liver has an enzyme called glucose 6-phosphatase that removes the phosphate so glucose can reenter the bloodstream |
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lipid and protein metabolism
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-Lipids and proteins can also be used for energy via the same pathways used for the metabolism of pyruvic acid -When more food energy is taken than needed for energy, we can’t store ATP for later -glucose is converted into glycogen and fat, and ATP production is inhibited |
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lipid metabolism
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-ATP levels rise after an energy-rich meal, production of ATP is inhibited Glucose doesn’t complete glycolysis to form pyruvic acid, and acetyl CoA already formed is joined together to produce a variety of lipids, including cholesterol, ketone bodies, and fatty acids- |
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lipogenesis
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-Fatty acids combine with glycerol to form triglycerides in the adipose tissue and liver
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fatty acid as energy source
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-β-oxidation: Enzymes remove acetic acid molecules from fatty acids to form acetyl CoA. -For every 2 carbons on the fatty acid chain, 1 acetyl CoA can be formed.Each acetyl CoA >10 ATP + 1 NADH + 1 FADH2 |
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Amino acid metabolism
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-Proteins provide nitrogen for the body -from dietary proteins needed to replace proteins in the body -If more consumed than needed,excess used for energy or converted into carb or fat -Our bodies can make 12 of the 20 from other molecules. Eight of them (9 in children) must come from the diet (ess.) |
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energy sources
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-Glucose and ketone bodies come from the liver-Fatty acids come from adipose tissue -Lactic acid and amino acids come from muscle and organs |
