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THIRD EDITION HUMAN PHYSIOLOGY AN INTEGRATED APPROACH Dee Unglaub Silverthorn, Ph.D. Chapter 4 Cellular Metabolism PowerPoint® Lecture Slide Presentation by Dr. Howard D. Booth, Professor of Biology, Eastern Michigan University Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings About this Chapter • Energy for synthesis and movement • Energy transformation • Enzymes and how they speed reactions • Metabolic pathways • ATP its formation and uses in metabolism • Synthesis of biologically important molecules Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Energy (E) Transfer Overview • Energy does work • Kinetic energy • Potential energy • Energy conversion Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Energy (E) Transfer Overview Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Figure 4-1: Energy transfer in the environment Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Chemosynthesis versus Photosynthesis Chemosynthesis • 6CO2 + 6H2S → C6H12O6 + 6S Needs heat added such as from hydrothermal vents in the deep ocean Photosynthesis • 2n CO2 + 2n H2O + photons → 2(CH2O)n + 2n O2 Occurs in Two Stages Stage 1: Light energy used to form ATP and NADPH Stage 2: Uses ATP and NADPH to reduce CO2 Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Energy and Chemical Reactions Figure 4-5: Energy transfer and storage in biological reactions Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Adenosine Triphosphate (ATP) • Source of immediately usable energy for the cell • Adenine-containing RNA nucleotide with three phosphate groups Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Adenosine Triphosphate (ATP) Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Figure 2.22 How ATP Drives Cellular Work Figure 2.23 Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Protein • Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds Figure 2.16 Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Structural Levels of Proteins • Primary – amino acid sequence • Secondary – alpha helices or beta pleated sheets Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Structural Levels of Proteins Figure 2.17a-c Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Structural Levels of Proteins • Tertiary – superimposed folding of secondary structures • Quaternary – polypeptide chains linked together in a specific manner Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Structural Levels of Proteins Figure 2.17d, e Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Fibrous and Globular Proteins • Fibrous proteins • Extended and strandlike proteins • Examples: keratin, elastin, collagen, and certain contractile fibers • Globular proteins • Compact, spherical proteins with tertiary and quaternary structures • Examples: antibodies, hormones, and enzymes Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Protein Synthesis Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Figure 4-34: Summary of transcription and translation Post – Translational protein modificaiton Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Figure 4-35: Post-translational modification and the secretory pathway Post – Translational protein modificaiton • Folding, cleavage, additions: glyco- lipo- proteins Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Characteristics of Enzymes • Most are globular proteins that act as biological catalysts • Holoenzymes consist of an apoenzyme (protein) and a cofactor (usually an ion) • Enzymes are chemically specific • Frequently named for the type of reaction they catalyze • Enzyme names usually end in -ase • Lower activation energy Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Characteristics of Enzymes Figure 2.19 Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Enzymes speed biochemical reactions Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Figure 4-8: Two models of enzyme binding sites Mechanism of Enzyme Action • Enzyme binds with substrate • Product is formed at a lower activation energy • Product is released Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Enzymes speed biochemical reactions • • • • Lower activation E Specific Cofactors Modulators • Acidity • Temperature • Competitive inhibitors • Allosteric • Concentrations Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Protein Denaturation • Reversible unfolding of proteins due to drops in pH and/or increased temperature Figure 2.18a Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Protein Denaturation • Irreversibly denatured proteins cannot refold and are formed by extreme pH or temperature changes Figure 2.18b Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Law of Mass Action • Defined: • Equlibrium • Reversible Figure 4-17: Law of mass action Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Types of Enzymatic Reactions • Oxidation–reduction • Hydrolysis–dehydration • Addition–subtraction exchange • Ligation Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Cell Metabolism • Pathways • Intermediates • Catabolic energy • Anabolic synthesis Figure 4-18b: A group of metabolic pathways resembles a road map Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Control of Metabolic Pathways • Feedback inhibition Figure 4-19: Feedback inhibition Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings ATP Production • Glycolysis • Pyruvate • Anaerobic respiration • Lactate production • 2 ATPs produced Figure 4-21: Overview of aerobic pathways for ATP Production Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Pyruvate Metabolism • Aerobic respiration • In mitochondria • Acetyl CoA and CO2 • Citric Acid Cycle or Kreb’s Cycle or TCA Cycle • Energy Produced from 1 Acetyl CoA • 1 ATP • 3 NADH • 1 FADH2 • Waste–2 CO2s Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Pyruvate Metabolism Figure 4-23: Pyruvate metabolism Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Electron Transport • High energy electrons • Energy transfer • ATP synthesized from ADP • H2O is a byproduct- In a typical individual this amounts to approximately 400 ml/day Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Electron Transport Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Figure 4-25: The electron transport system and ATP synthesis Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Biomolecules Catabolized to make ATP • Complex Carbohydrates • Glycogen catabolism • Liver storage • Muscle storage • Glucose produced Figure 4-26: Glycogen catabolism Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Protein Catabolism • Deaminated • Conversion • Glucose • Acetyl CoA Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Protein Catabolism Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Figure 4-27: Protein catabolism and deamination Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Lipid Catabolism • Higher energy content • Triglycerides to glycerol • Glycerol • Fatty acids • Ketone bodies - liver Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Fat mass, adipose tissue and energy stores Liver triglycerides = 450 kcal Muscle triglycerides = Liver glycogen = 400 kcal 3000 kcal Muscle glycogen = 2500 kcal Adipose tissue triglycerides = 120,000 kcal Data for a 70 kg lean subject. Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Synthetic (Anabolic) pathways • Glycogen synthesis • Liver storage • Glucose to glycogen • Gluconeogenesis • Amino acids • Glycerol • Lactate Figure 4-29: Gluconeogenesis Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Lipogenesis • Acetyl Co A • Glycerol • Fatty acids • Triglycerides Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Figure 4-30: Lipid synthesis Lipogenesis Figure 4-30: Lipid synthesis Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings Summary • Energy: chemical, transport, mechanical work • Reactions: reactants, activation energy, directions • Enzymes: characteristics, speed & control pathways • Metabolism: catabolic, anabolic • ATP production: anaerobic, aerobic, glycolysis, • citric acid cycle, & electron transport • Synthesis of carbohydrates, lipids and proteins Copyright Copyright©©2004 2004Pearson PearsonEducation, Education,Inc., Inc.,publishing publishingas asBenjamin BenjaminCummings Cummings
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