Textbook Question
Each of these reactions is involved in one of the four stages of metabolism shown in Figure 21.4. Identify the stage in which each reaction occurs.
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b. Oxidation of NADH coupled with synthesis of ATP
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Ch.21 The Generation of Biochemical Energy
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187
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Table of contents
- Ch.1 Matter and Measurements27
- Ch.2 Atoms and the Periodic Table20
- Ch.3 Ionic Compounds8
- Ch.4 Molecular Compounds23
- Ch.5 Classification & Balancing of Chemical Reactions12
- Ch.6 Chemical Reactions: Mole and Mass Relationships28
- Ch.7 Chemical Reactions: Energy, Rate and Equilibrium64
- Ch.8 Gases, Liquids and Solids24
- Ch.9 Solutions52
- Ch.10 Acids and Bases25
- Ch.11 Nuclear Chemistry22
- Ch.12 Introduction to Organic Chemistry: Alkanes57
- Ch.13 Alkenes, Alkynes, and Aromatic Compounds47
- Ch.14 Some Compounds with Oxygen, Sulfur, or a Halogen50
- Ch.15 Aldehydes and Ketones45
- Ch.16 Amines42
- Ch.17 Carboxylic Acids and Their Derivatives57
- Ch.18 Amino Acids and Proteins82
- Ch.19 Enzymes and Vitamins63
- Ch.20 Carbohydrates44
- Ch.21 The Generation of Biochemical Energy65
- Ch.22 Carbohydrate Metabolism45
- Ch.23 Lipids42
- Ch.24 Lipid Metabolism33
- Ch.25 Protein and Amino Acid Metabolism24
- Ch.26 Nucleic Acids and Protein Synthesis45
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187Not the one you use?Change textbook
Chapter 21, Problem 19
The reduced coenzymes NADH and FADH2 are oxidized in the ETS. What is the final electron acceptor of the ETS? What is the function of the H+ ion in ATP synthesis?
Verified step by step guidance1
Step 1: Understand the Electron Transport System (ETS). The ETS is a series of protein complexes and electron carriers located in the inner mitochondrial membrane. It is responsible for transferring electrons from reduced coenzymes (NADH and FADH₂) to a final electron acceptor, while simultaneously creating a proton gradient.
Step 2: Identify the final electron acceptor in the ETS. In the ETS, electrons are passed through a series of complexes and carriers, ultimately being transferred to molecular oxygen (O₂), which is the final electron acceptor. Oxygen combines with electrons and protons (H⁺) to form water (H₂O).
Step 3: Explain the role of H⁺ ions in the ETS. As electrons move through the ETS, energy is released and used to pump H⁺ ions from the mitochondrial matrix into the intermembrane space, creating a proton gradient (electrochemical gradient).
Step 4: Describe the function of the H⁺ ion in ATP synthesis. The H⁺ ions flow back into the mitochondrial matrix through ATP synthase, a protein complex that uses the energy from this flow (proton motive force) to synthesize ATP from ADP and inorganic phosphate (Pi). This process is called oxidative phosphorylation.
Step 5: Summarize the importance of the ETS and H⁺ ions. The ETS is essential for cellular respiration, as it generates the majority of ATP in aerobic organisms. The H⁺ ion gradient is the driving force for ATP synthesis, making it a critical component of energy production in cells.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Electron Transport System (ETS)
The Electron Transport System (ETS) is a series of protein complexes located in the inner mitochondrial membrane that facilitate the transfer of electrons from reduced coenzymes like NADH and FADH₂ to molecular oxygen. This process generates a proton gradient across the membrane, which is essential for ATP synthesis. The ETS is crucial for cellular respiration, as it is the primary pathway for ATP production in aerobic organisms.
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Final Electron Acceptor
In the context of the ETS, the final electron acceptor is molecular oxygen (O₂). As electrons are transferred through the protein complexes of the ETS, they ultimately reduce oxygen to form water. This step is vital for maintaining the flow of electrons through the system and is a key reason why oxygen is essential for aerobic respiration.
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Proton Gradient and ATP Synthesis
The proton gradient created by the ETS is critical for ATP synthesis through a process called chemiosmosis. As protons (H⁺ ions) accumulate in the intermembrane space, they create a potential energy difference across the membrane. ATP synthase, an enzyme embedded in the membrane, utilizes this gradient to drive the conversion of ADP and inorganic phosphate into ATP as protons flow back into the mitochondrial matrix.
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Related Practice
Textbook Question
Why, do you suppose, the coenzyme for the reaction in the citric acid cycle that is catalyzed by succinate dehydrogenase is FAD and not NAD+?
Textbook Question
Which of the reactants in the citric acid cycle have two chiral carbon atoms?
Textbook Question
Identify the participants in the citric acid cycle that contain alcohol groups. Identify these groups as primary, secondary, or tertiary alcohols.
Textbook Question
Each of these reactions is involved in one of the four stages of metabolism shown in Figure 21.4. Identify the stage in which each reaction occurs.
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c. Conversion of glucose to acetyl-CoA
Textbook Question
Each of these reactions is involved in one of the four stages of metabolism shown in Figure 21.4. Identify the stage in which each reaction occurs.
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a. Hydrolysis of starch to produce glucose
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