BIOCHEMISTRY - L. Stryer - 1984

VOLUME 2

PART II GENERATION AND STORAGE OF METABOLIC ENERGY

CHAPTER 11 METABOLISM: BASIC CONCEPTS AND DESIGN

    11.1. Free Energy Is the Most Useful Thermodynamic Function in Biochemistry

    11.4. ATP Is the Universal Energy Currency in Biological Systems

    11.7. ATP Hydrolysis Shifts the Equilibrium of Coupled Reactions by a Factor of 108

    11.10. Coenzyme A Acts as a Universal Acyl-Group Carrier

    Summary

PROBLEMS

CHAPTER 12. GLYCOLYSIS

    12.1. Nomenclature and Conformation of Monosaccharides

    Why

    12.2. Overview of Key Structures and Reactions

    12.7. Formation of Pyruvate and Generation of the Second ATP Molecule

    12.10. Pyruvate Can Be Converted into Ethanol, Lactate, or Acetyl-Coenzyme A

    12.13. Aldolase Forms a Schiff Base Intermediate with Dihydroxyacetone Phosphate

    12.16. Enol Phosphates Possess a High Group-Transfer Potential

    Summary

APPENDIX. STEREOCHEMICAL RELATIONSHIPS OF CERTAIN SUGARS

PROBLEMS

CHAPTER 13. THE CITRIC ACID CYCLE

    13.1. Formation of Acetyl-Coenzyme A from Pyruvate

    13.3. Oxaloacetate Condenses with Acetyl-Coenzyme A to Form Citrate

    13.6. Oxidative Decarboxylation of Alpha-Ketoglutarate Yields Succinyl-CoA

    13.9. Stoichiometry of the tricarboxylic acid cycle

    13.11. Variations on a multienzyme theme: the alpha-oxoglutarate dehydrogenase complex

    13.14. Stereospecific hydrogen transfer by NAD+ dehydrogenases

    13.17. Regulation of the pyruvate dehydrogenase complex

    Conclusions

APPENDIX. RS-DESIGNATION OF CHIRALITY

QUESTIONS AND PROBLEMS

CHAPTER 14. OXIDATIVE PHOSPHORYLATION

    14.1. Oxidative phosphorylation takes place in mitochondria

    14.2. Redox potentials and free-energy changes

    14.4. Flavin, iron-sulfur complexes, quinone, and heme groups transfer electrons from NADH to O2

    14.5. The coupling of oxidation and phosphorylation is mediated by a proton gradient

    14.7. Protons are pumped out by symmetrically or asymmetrically oriented transmembrane complexes

    14.9. Electrons from cytoplasmic NADH enter mitochondria via the glycerophosphate shuttle

    14.12. Complete oxidation of glucose yields 36 ATP

    14.15. Three-dimensional structure of cytochrome c

    14.18. Transmission of proton-motive force through proton gradients: a central motif of bioenergetics

    Conclusions

QUESTIONS AND PROBLEMS

CHAPTER 15. THE PENTOSE PHOSPHATE PATHWAY AND GLUCONEOGENESIS

    15.1. The pentose phosphate pathway generates ATP and synthesizes five-carbon sugars

    15.2. Two molecules of NADPH are generated during the conversion of glucose-6-phosphate to ribulose-5-phosphate

    15.5. The rate of the pentose phosphate pathway is regulated by the concentration of NADP+

    15.8. Thiamine pyrophosphate, the prosthetic group of transketolase, transfers activated aldehydes

    15.11. Glucose-6-phosphate dehydrogenase deficiency as a cause of drug-induced hemolytic anemia

    15.14. Gluconeogenesis Is Not the Reverse of Glycolysis

    15.17. Oxaloacetate Is Transported to the Cytosol via a Shuttle Mechanism and Converted into Phosphoenolpyruvate

    15.20. Substrate Cycles Amplify Metabolic Signals and Heat Production

    Summary

QUESTIONS AND PROBLEMS

CHAPTER 16. GLYCOGEN AND DISACCHARIDE METABOLISM

    16.1. Phosphorylase Catalyzes the Phosphorolytic Cleavage of Glycogen to Glucose-1-Phosphate

    16.2. Glycogen Breakdown Also Requires a Debranching Enzyme

    16.5. Synthesis and Breakdown of Glycogen Occur via Different Pathways

    16.8. The Branching Enzyme Forms alpha-1,6-Linkages

    16.11. Phosphorylase Is Activated by Phosphorylation of a Specific Serine Residue

    16.14. Glycogen Synthase Is Inactivated by Phosphorylation of a Specific Serine Residue

    16.18. Liver Glycogen Metabolism Regulates Blood Glucose Levels

    16.22. Lactose Synthesis Is Controlled by a Modifying Subunit

    Summary

QUESTIONS AND PROBLEMS

CHAPTER 17. FATTY ACID METABOLISM

    17.1. Fatty Acid Nomenclature

    17.3. Triacylglycerols (Triglycerides) Are Highly Concentrated Energy Reserves

    17.7. Carnitine Transports Activated Long-Chain Fatty Acids into the Mitochondrial Matrix

    17.10. An Isomerase and an Epimerase Are Required for the Oxidation of Unsaturated Fatty Acids

    17.14. Animals Cannot Convert Fatty Acids into Glucose

    17.17. Intermediates in Fatty Acid Synthesis Are Attached to an Acyl Carrier Protein

    17.20. In Eukaryotes, Fatty Acids Are Synthesized by a Multienzyme Complex

    17.23. Fatty Acid Elongation and Desaturation Are Carried Out by Additional Enzyme Systems

    Summary

QUESTIONS AND PROBLEMS

CHAPTER 18. AMINO ACID DEGRADATION AND THE UREA CYCLE

    18.1. α-Amino groups are converted to ammonium ion via oxidative deamination of glutamate

    18.3. Serine and threonine can undergo direct deamination

    18.6. Inherited enzyme deficiencies of the urea cycle lead to hyperammonemia

    18.9. The C4-amino acid family: aspartate and asparagine are converted to oxaloacetate

    18.12. Enzymes containing cobalamin (vitamin B12) as a prosthetic group catalyze rearrangement and methylation reactions

    18.15. Leucine is degraded to acetyl-coenzyme A and acetoacetyl-coenzyme A

    18.18. Impaired phenylalanine hydroxylation can result in severe intellectual disability

    Summary

QUESTIONS AND PROBLEMS

CHAPTER 19. PHOTOSYNTHESIS

    19.1. Discovery of the overall equation of photosynthesis

    19.2. Chlorophylls function as photoreceptor molecules

    19.5. Oxygen evolved in photosynthesis is derived from water

    19.9. Photosystem I generates NADPH via reduced ferredoxin

    19.12. ATP can also be formed during cyclic electron flow through photosystem I

    19.15. CO2 reacts with ribulose bisphosphate to yield two molecules of phosphoglycerate

    19.18. Regulation of the Calvin cycle

    19.21. The purple membrane protein of halobacteria pumps protons to drive ATP synthesis

    Summary

QUESTIONS AND PROBLEMS

PART III. BIOSYNTHESIS OF MACROMOLECULAR PRECURSORS

CHAPTER 20. BIOSYNTHESIS OF MEMBRANE LIPIDS AND STEROID HORMONES

    20.1. Phosphatidic acid is an intermediate in the synthesis of phosphoacylglycerols and triacylglycerols

    20.4. Phosphoacylglycerols can also be synthesized from preformed residues

    20.8. Tay-Sachs disease: an inherited defect in ganglioside degradation

    20.11. Synthesis of isopentenyl pyrophosphate, an activated intermediate in cholesterol formation

    20.15. Cholesterol synthesis in the liver is inhibited by dietary cholesterol

    20.18. Absence of LDL receptors leads to hypercholesterolemia and premature atherosclerosis

    20.22. Pregnenolone is formed from cholesterol by side-chain cleavage

    20.25. Deficient 21-hydroxylase activity leads to virilism and adrenal hyperplasia

    Summary

QUESTIONS AND PROBLEMS

CHAPTER 21. BIOSYNTHESIS OF AMINO ACIDS AND HEME

    21.1. Microorganisms use ATP and a strong reducing agent to convert N2 to NH4

    21.3. Amino acids are synthesized from tricarboxylic acid cycle intermediates and other important metabolites

    21.7. S-adenosylmethionine is the primary methyl group donor

    21.10. Histidine is synthesized from ATP, PRPP, and glutamine

    21.13. Amino acids are precursors to numerous other biomolecules

    Summary

QUESTIONS AND PROBLEMS

CHAPTER 22. BIOSYNTHESIS OF NUCLEOTIDES

    22.1. Nomenclature of bases, nucleosides, and nucleotides

    22.3. Phosphoribosyl pyrophosphate is the donor of the ribose-phosphate moiety in nucleotides

    22.6. Purine bases can be salvaged via PRPP-dependent pathways

    22.11. Nucleoside mono-, di-, and triphosphates are interconvertible

    22.15. Deoxyribonucleotides are synthesized by the reduction of ribonucleoside diphosphates

    22.18. ATP is a precursor of NAD+, FAD, and coenzyme A

    22.21. Birds and Terrestrial Reptiles Excrete Uric Acid Instead of Urea to Conserve Water

    Summary

QUESTIONS AND PROBLEMS

CHAPTER 23. METABOLIC INTEGRATION

    23.1. Metabolic Strategies: An Overview

    23.2. Recurring Motifs in Metabolic Regulation

    23.4. Key Intermediates: Glucose-6-Phosphate, Pyruvate, and Acetyl-CoA

    23.6. Hormonal Regulation of Energy Metabolism

    Summary

ANSWERS TO QUESTIONS AND PROBLEMS