Mitochondria and Their Functions
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Questions and Answers

What is the total number of ATP molecules consumed during the investment phase of glycolysis?

  • 2 (correct)
  • 1
  • 0
  • 36

    • What defines oxidation in metabolic terms?

  • Loss of electrons (correct)
  • Gain of electrons
  • Production of O2
  • Production of free radicals

    • Which of the following does glycolysis not produce?

  • ATP
  • Pyruvate
  • NADH
  • FADH2 (correct)

    • What is the primary role of mitochondria in the cell?

    <p>Produce energy</p> Signup and view all the answers

    What enzyme is responsible for converting NADH to NADPH?

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

    What term is used to describe the singular form of mitochondria?

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

    Which of the following is a product of cellular respiration?

    <p>CO2</p> Signup and view all the answers

    Which molecule is vital for carrying electrons in cellular respiration?

    <p>NAD+</p> Signup and view all the answers

    What is the net ATP yield from mitochondrial NADH during oxidative phosphorylation?

    <p>3 ATP/NADH</p> Signup and view all the answers

    Which process refers to the production of anabolic molecules from metabolic intermediates in the mitochondria?

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

    How much energy is released when ATP is hydrolyzed to ADP and Pi?

    <p>~7.3 kcal/mole</p> Signup and view all the answers

    What is the actual ATP yield range from FADH2 during oxidative phosphorylation?

    <p>1.5 - 2 ATP/FADH2</p> Signup and view all the answers

    Which of the following is NOT a role of ATP in the cell?

    <p>Synthesis of glucose</p> Signup and view all the answers

    What is the primary energy currency produced during cellular respiration in mitochondria?

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

    What metabolic process does pyruvate enter after glycolysis in the mitochondria?

    <p>Citric acid cycle</p> Signup and view all the answers

    What is the role of pyruvate dehydrogenase (PDH) in mitochondrial metabolism?

    <p>It converts pyruvate into Acetyl-CoA.</p> Signup and view all the answers

    Which of the following components is released as a byproduct during the conversion of pyruvate to Acetyl-CoA?

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

    What is the anaerobic fate of pyruvate when oxygen is not available?

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

    Which of the following best describes cataplerosis?

    <p>Anabolic processes using metabolic intermediates</p> Signup and view all the answers

    What key function do mitochondria serve in relation to calcium?

    <p>They store calcium.</p> Signup and view all the answers

    What role does apoptosis serve in cellular function?

    <p>Regulating the cell life cycle</p> Signup and view all the answers

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

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

    What is the initial substrate for glycolysis?

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

    What is the primary role of porin in the outer mitochondrial membrane?

    <p>Maintaining outer membrane permeability</p> Signup and view all the answers

    Which components are found in the mitochondrial matrix?

    <p>Circular DNA and ribosomes</p> Signup and view all the answers

    How is mitochondrial DNA primarily inherited?

    <p>Primarily from the mother via oocyte mitochondria</p> Signup and view all the answers

    What characterizes the inner mitochondrial membrane?

    <p>Contains folds known as cristae</p> Signup and view all the answers

    What process allows for the selective degradation of dysfunctional mitochondria?

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

    What is the main function of the electron transport chain located in the inner mitochondrial membrane?

    <p>Generate ATP through oxidative phosphorylation</p> Signup and view all the answers

    What substance is NOT able to pass freely through the inner mitochondrial membrane?

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

    What does mitochondrial biogenesis refer to?

    <p>Creation of new mitochondria</p> Signup and view all the answers

    Mitochondrial DNA has a higher mutation rate compared to nuclear DNA. What is one reason for this?

    <p>It has fewer repair mechanisms</p> Signup and view all the answers

    Which statement accurately reflects the composition of the outer mitochondrial membrane?

    <p>It is about 50% protein</p> Signup and view all the answers

    What is the first step in the TCA cycle?

    <p>Citrate is formed from acetyl-CoA and oxaloacetate</p> Signup and view all the answers

    Which of the following molecules is a product of β-oxidation?

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

    How many NADH molecules are produced per Acetyl-CoA in β-oxidation?

    <p>3</p> Signup and view all the answers

    Which enzyme is responsible for converting pyruvate into Acetyl-CoA?

    <p>Pyruvate dehydrogenase (PDH)</p> Signup and view all the answers

    What happens to the 2 carbons lost during the TCA cycle?

    <p>They are released as CO2</p> Signup and view all the answers

    What is the role of NADH and FADH2 in the TCA cycle?

    <p>They donate electrons to the electron transport chain</p> Signup and view all the answers

    Which of the following statements is true regarding glycolysis?

    <p>It primarily operates in the cytoplasm</p> Signup and view all the answers

    What are the total reducing equivalents produced from one cycle of the TCA cycle?

    <p>3 NADH and 1 FADH2</p> Signup and view all the answers

    Which of the following is NOT a role of mitochondria?

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

    What is the outcome of the TCA cycle in terms of carbon regeneration?

    <p>It regenerates oxaloacetate</p> Signup and view all the answers

    Study Notes

    ### Mitochondria

    • The mitochondria is the "powerhouse" of the cell with many other roles
    • Structure:
      • Outer membrane: permeable to small molecules
      • Inner membrane: impermeable to most molecules
      • Matrix: contains mtDNA, enzymes, and ribosomes

    ### Mitochondrial DNA (mtDNA)

    • mtDNA encodes 13 proteins, all part of the ETC
    • Inherited primarily from mothers
    • Mutates more quickly than nuclear DNA
    • Used in tracking human migration and evolution

    ### Mitochondrial Dynamics

    • Biogenesis: creation of new mitochondria
    • Mitophagy: selective degradation of old/dysfunctional mitochondria
    • Mitochondrial fusion: mitochondria fusing with each other
    • Mitochondrial fission: mitochondria splitting in two
    • Fusion & Fission effect the number, length, and degree of interconnectivity

    ### Roles of Mitochondria

    • Cellular Respiration: ATP production - Energy
    • Cataplerosis: Metabolic intermediates from the TCA cycle used for anabolism
    • Calcium homeostasis: Signal transduction
    • Apoptosis: Cell life cycle

    ### Carbohydrate Metabolism in Mitochondria

    • Glycolysis: breakdown of glucose in the cytosol
      • Produces pyruvate, ATP, and NADH
      • Pyruvate either enters the mitochondrial matrix or undergoes fermentation

    ### Pyruvate Entry

    • Pyruvate Dehydrogenase (PDH):
      • Multienzyme complex
      • Highly regulated
      • Converts pyruvate to acetyl-CoA
      • Acetyl-CoA is further metabolized in the TCA cycle

    ### TCA Cycle (or Krebs Cycle)

    • Occurs in the mitochondrial matrix
    • Acetyl-CoA is condensed with oxaloacetate to form citrate
    • Citrate is then metabolized, generating CO2, ATP, NADH, and FADH2

    ### Oxidative Phosphorylation

    • NADH and FADH2 are transported to the ETC
    • ETC uses electrons from NADH and FADH2 to pump protons out of the matrix, creating a proton gradient
    • ATP Synthase uses the potential energy of the proton gradient to produce ATP

    ### ATP: Energy Currency

    • ATP is used to power most of the energy-consuming activities of cells

    ### ATP: Other Functions

    • Cell signaling: ATP used in signal transduction pathways
    • Anabolism: ATP used in synthesis of RNA and DNA

    ### Cataplerosis

    • Cataplerosis is the use of TCA cycle intermediates to synthesize anabolic molecules

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    HSS2305 Lecture 6 on Mitochondria PDF

    Description

    Explore the fascinating world of mitochondria, the powerhouse of the cell. This quiz covers their structure, the role of mitochondrial DNA, and the various dynamics such as biogenesis and mitophagy. Understand how mitochondria contribute to cellular respiration and metabolic processes.

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