Biology Chapter on Oxidative Phosphorylation
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Questions and Answers

Which statement correctly describes the flow of electrons in the electron transport chain (ETC)?

  • Electrons are transferred from lower to higher energy carriers.
  • Electrons accumulate in the intermembrane space and are not transferred.
  • Electrons fall to successively lower energy levels as they move through the ETC. (correct)
  • Electrons are continuously at a high energy state throughout the ETC.

    • What role do NADH and FADH2 play in the process of oxidative phosphorylation?

  • They directly synthesize ATP without any further reactions.
  • They act as final electron acceptors in the electron transport chain.
  • They are converted back into NAD+ and FAD. (correct)
  • They transfer electrons directly to O2.

    • What is the average ATP yield from one molecule of NADH during oxidative phosphorylation?

  • 5-6 ATP
  • 2-3 ATP (correct)
  • 3-4 ATP
  • 1-2 ATP

    • In the context of oxidative phosphorylation, what happens to the electrons after they pass through the ETC?

    <p>They are ultimately transferred to oxygen to form water.</p> Signup and view all the answers

    How do NADH and FADH2 contribute to the regeneration of themselves during cellular respiration?

    <p>By being converted back through the electron transport chain.</p> Signup and view all the answers

    What is the relationship between the electron transport chain and the production of ATP?

    <p>The ETC creates a proton gradient that drives ATP synthesis.</p> Signup and view all the answers

    What is the function of the intermembrane space in the mitochondrial electron transport chain?

    <p>It accumulates protons, contributing to the electrochemical gradient.</p> Signup and view all the answers

    During oxidative phosphorylation, which of the following accurately describes FADH2's contribution to ATP production?

    <p>It contributes less to ATP yield compared to NADH.</p> Signup and view all the answers

    What key outcome results from the high-energy electrons moving through the carriers of the electron transport chain?

    <p>They release free energy used to pump protons across the membrane.</p> Signup and view all the answers

    What role do H+ ions play in the ATP synthesis process?

    <p>They provide energy by creating a gradient between the intermembrane space and the matrix.</p> Signup and view all the answers

    Which factor primarily determines the total ATP yield from one glucose molecule in aerobic respiration?

    <p>The efficiency of the electron transport chain.</p> Signup and view all the answers

    What is the primary function of glycolysis in cellular respiration?

    <p>To convert glucose into pyruvate</p> Signup and view all the answers

    What is the end product of pyruvate decarboxylation?

    <p>Acetyl CoA</p> Signup and view all the answers

    What happens to NADH during anaerobic respiration?

    <p>It is converted back to NAD+ to continue glycolysis.</p> Signup and view all the answers

    During the electron transport chain, which complex is primarily responsible for using NADH?

    <p>Complex I.</p> Signup and view all the answers

    Which molecule is primarily produced during glycolysis from the breakdown of glucose?

    <p>NADH</p> Signup and view all the answers

    What is the primary consequence of the lactic acid buildup in muscles during intense exercise?

    <p>It causes muscle fatigue and reduced functionality.</p> Signup and view all the answers

    In which cellular structure does the electron transport chain occur?

    <p>Inner mitochondrial membrane</p> Signup and view all the answers

    What role does NADH play in oxidative phosphorylation?

    <p>It donates electrons to the electron transport chain</p> Signup and view all the answers

    What is the final electron acceptor in the electron transport chain?

    <p>Oxygen.</p> Signup and view all the answers

    What characterizes the intermembrane space of mitochondria?

    <p>Low pH due to proton accumulation</p> Signup and view all the answers

    How many ATP molecules can be generated from one molecule of glucose during aerobic respiration?

    <ol start="32"> <li></li> </ol> Signup and view all the answers

    Under which condition does pyruvate degrade into lactate instead of acetyl CoA?

    <p>When oxygen is limited or unavailable.</p> Signup and view all the answers

    What is the final electron acceptor in the electron transport chain?

    <p>Oxygen</p> Signup and view all the answers

    What is a significant byproduct of the complete oxidation of glucose?

    <p>Water.</p> Signup and view all the answers

    How many ATP molecules are synthesized from one molecule of glucose during glycolysis?

    <p>2</p> Signup and view all the answers

    What would most likely occur in the absence of the enzyme involved in the first step of converting glycogen to glucose?

    <p>Accumulation of glycogen</p> Signup and view all the answers

    What role do FADH2 contribute in ATP synthesis compared to NADH?

    <p>It enters the electron transport chain at a later stage, yielding fewer ATP.</p> Signup and view all the answers

    What is the impact of FADH2 in the electron transport chain compared to NADH?

    <p>FADH2 contributes fewer protons to the intermembrane space</p> Signup and view all the answers

    What is released during the transformation of pyruvate into Acetyl CoA?

    <p>Carbon Dioxide</p> Signup and view all the answers

    In the Citric Acid Cycle, which molecule is primarily regenerated to continue the cycle?

    <p>Oxaloacetate</p> Signup and view all the answers

    How many molecules of ATP are generated from one complete cycle of the Citric Acid Cycle?

    <p>2</p> Signup and view all the answers

    Which of the following is NOT a product of the Citric Acid Cycle?

    <p>Pyruvate</p> Signup and view all the answers

    During oxidative phosphorylation, where are most of the electron carrier molecules located?

    <p>Inner mitochondrial membrane</p> Signup and view all the answers

    What is the primary role of NADH and FADH2 in cellular respiration?

    <p>To donate electrons to the ETC</p> Signup and view all the answers

    Where does the processing of Acetyl CoA mainly release energy to form GTP?

    <p>Mitochondrial matrix</p> Signup and view all the answers

    What happens to hydrogen atoms during the processes of the Citric Acid Cycle and the Electron Transport Chain?

    <p>They are removed and contribute to creating ATP later</p> Signup and view all the answers

    What is the main source of oxygen used in the formation of carbon dioxide during the Citric Acid Cycle?

    <p>Molecules involved in the cycle</p> Signup and view all the answers

    In oxidative phosphorylation, what is primarily produced by the electron transport chain?

    <p>ATP</p> Signup and view all the answers

    Study Notes

    Cellular Metabolism Overview

    • Cellular respiration occurs under aerobic conditions, producing a maximum of 32 ATP from one glucose molecule.
    • Breakdown includes:
      • 2 ATP from glycolysis
      • 2 ATP from the TCA (Krebs) cycle
      • 3 ATP from FADH2 (2 molecules of FADH2 yield 3 ATP)
      • 25 ATP from NADH (10 NADH yield 25 ATP)

    Oxidative Phosphorylation

    • Oxygen plays a crucial role in oxidative phosphorylation by accepting electrons and producing water.
    • NADH and FADH2 donate electrons to the electron transport chain (ETC), regenerating NAD+ and FAD for reuse in metabolic processes.
    • Each NADH generates approximately 2.5 ATP, while each FADH2 generates around 1.5 ATP.
    • High-energy electrons fall through multiple carriers in the ETC, releasing energy to pump H+ ions into the intermembrane space.
    • The resulting H+ gradient powers ATP synthase to synthesize ATP as H+ ions return to the mitochondrial matrix.
    • Oxygen serves as the final electron acceptor to maintain the flow of electrons in the chain.

    Anaerobic Conditions

    • In the absence of oxygen, pyruvate is converted to lactate instead of acetyl CoA.
    • Cellular respiration is limited to glycolysis, generating only 2 ATP.
    • NADH produced during glycolysis is reused to convert pyruvate to lactic acid, preventing buildup of NAD+.
    • Metabolic activities at high intensity can lead to lactic acid accumulation, causing muscle fatigue and dysfunction.

    Key Processes in Cellular Respiration

    • Pyruvate Decarboxylation:

      • Converts pyruvate to Acetyl CoA as it enters the mitochondrial matrix, releasing one CO2 and generating one NADH per pyruvate.

    • Citric Acid Cycle (TCA Cycle):

      • Consists of 8 enzymatic reactions, regenerating oxaloacetate and releasing two CO2 per cycle.
      • Produces 6 NADH and 2 FADH2 while generating 2 ATP (1 per cycle).
      • Hydrogen atoms from substrates are captured in carrier molecules (NAD+ and FAD) for use in the ETC.

    Glycolysis

    • Glycolysis breaks down one glucose molecule into two pyruvate molecules through a series of 10 enzyme-mediated reactions.
    • Produces:
      • 2 NADH (from NAD+)
      • 2 ATP directly from substrate-level phosphorylation.
    • Several metabolic diseases can impact glycolysis; for example, McArdle disease results from a deficiency in the enzyme needed to convert glycogen to glucose.

    Electron Transport Chain (ETC)

    • Resides in the inner mitochondrial membrane, comprising a series of electron carriers.
    • Extracts high-energy electrons from NADH and FADH2, facilitating the majority of ATP production.
    • The process transforms energy between mitochondrial compartments (matrix to membrane) to create a usable form of energy (ATP) for the cell.

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    Cellular Respiration PDF

    Description

    Explore the process of oxidative phosphorylation as it pertains to cellular respiration. This quiz focuses on the transfer of electrons and the role of oxygen in ATP production. Dive into the intricacies of the intermembrane space and its significance in energy metabolism.

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