Mitochondria and Cellular Respiration
84 Questions
4 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of mitochondria in eukaryotic cells?

  • Protein synthesis
  • DNA replication
  • Energy production and metabolic processes (correct)
  • Cell division

    • What is the role of the intermembrane space in mitochondria?

  • Helps establish a proton gradient essential for ATP production (correct)
  • Responsible for ATP synthesis
  • Site for the TCA cycle
  • Contains mitochondrial DNA

    • Which statement best describes cellular respiration?

  • It is a process that converts nutrients into ATP using oxygen, producing CO2 and H2O. (correct)
  • It occurs exclusively in the cytoplasm of prokaryotic cells.
  • It converts glucose and oxygen directly into amino acids.
  • It is a method of anaerobic energy production.

    • What is the significance of catabolic pathways in relation to cellular respiration?

    <p>They convert energy from glucose into usable forms.</p> Signup and view all the answers

    Which of the following structures of mitochondria is responsible for the synthesis of ATP?

    <p>Cristae of the inner membrane</p> Signup and view all the answers

    What is the main advantage of aerobic respiration over anaerobic respiration?

    <p>It results in a higher energy yield.</p> Signup and view all the answers

    Which process is most directly regulated by cellular respiration?

    <p>Energy balance and metabolic homeostasis</p> Signup and view all the answers

    How do the structural features of mitochondria contribute to their function?

    <p>The highly folded inner membrane increases the surface area for ATP production.</p> Signup and view all the answers

    Which compound has the highest free energy release according to the provided data?

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

    Which enzyme classification does NOT belong to oxidoreductases?

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

    In the context of NAD+ and its functions, what is primarily produced during catabolic reactions?

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

    Which of the following statements best describes the role of NADPH in metabolism?

    <p>It provides reducing power in anabolic reactions.</p> Signup and view all the answers

    Which high-energy compound has a free energy change closest to -10 kcal/mol?

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

    What is the primary function of enzymes classified as oxidases?

    <p>To transfer electrons in oxidation-reduction reactions.</p> Signup and view all the answers

    Among the listed coenzymes, which one is specifically a phosphorylated form of NADH?

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

    Which of the following statements about anabolic reactions is correct?

    <p>They require energy input to convert simple molecules into complex ones.</p> Signup and view all the answers

    What substance is produced during pyruvate oxidation besides Acetyl-CoA?

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

    Which statement best describes the role of oxidative phosphorylation in cellular respiration?

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

    In biological oxidation, what is primarily converted into usable energy?

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

    What is the maximum energy yield from complete glucose oxidation, represented as Gibbs free energy?

    <p>-2,864 kJ/mol</p> Signup and view all the answers

    Which role do enzymes and co-enzymes play in biological oxidations?

    <p>They facilitate the oxidation of substrates.</p> Signup and view all the answers

    How is an oxidizing agent defined in a redox reaction?

    <p>A substance that gains electrons.</p> Signup and view all the answers

    Which of the following is NOT a product of the TCA cycle?

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

    What characterizes a reduction reaction in redox chemistry?

    <p>Gain of electrons.</p> Signup and view all the answers

    What part of cellular respiration undergoes electron transport to produce ATP?

    <p>Oxidative phosphorylation.</p> Signup and view all the answers

    Which of the following statements about biological oxidations is correct?

    <p>They involve both oxidation and reduction processes.</p> Signup and view all the answers

    What is the primary role of anaplerotic reactions in the TCA cycle?

    <p>To replenish depleted cycle intermediates</p> Signup and view all the answers

    Which of the following compounds can serve as a precursor for amino acids in the TCA cycle?

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

    Which enzyme is primarily responsible for converting pyruvate into oxaloacetate?

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

    How does the regulation of the TCA cycle occur in response to cellular energy levels?

    <p>Through feedback mechanisms responding to changes in ATP, ADP, and NADH levels</p> Signup and view all the answers

    Which metabolic waste product is primarily removed through the actions of the TCA cycle?

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

    In what capacity is the TCA cycle described as an amphibolic pathway?

    <p>Serves both catabolic and anabolic processes</p> Signup and view all the answers

    Which of the following intermediates is not directly involved in the TCA cycle but serves a crucial biosynthetic role?

    <p>α-ketoglutarate</p> Signup and view all the answers

    Which step in the TCA cycle is catalyzed by citrate synthase, and what is its significance?

    <p>The initial step of converting oxaloacetate to citrate; it initiates the cycle</p> Signup and view all the answers

    What is the role of pyruvate dehydrogenase kinase in pyruvate dehydrogenase regulation?

    <p>It inhibits pyruvate dehydrogenase by phosphorylating it.</p> Signup and view all the answers

    Which enzyme catalyzes the conversion of citrate to isocitrate?

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

    Which of the following statements about the TCA cycle is TRUE?

    <p>Acetyl-CoA condenses with oxaloacetate to form citrate.</p> Signup and view all the answers

    What is produced during the oxidative decarboxylation of alpha-ketoglutarate?

    <p>One NADH molecule and CO2</p> Signup and view all the answers

    In which part of the cell does the TCA cycle predominantly occur?

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

    Which compound acts as an inhibitor of pyruvate dehydrogenase?

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

    Which step of the TCA cycle produces FADH2?

    <p>Conversion of succinate to fumarate</p> Signup and view all the answers

    What is the total output of NADH produced from one acetyl-CoA molecule in the TCA cycle?

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

    Which enzyme is responsible for the production of GTP from succinyl-CoA?

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

    What type of reaction occurs when malate is converted back into oxaloacetate?

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

    Identify the main function of the TCA cycle.

    <p>Generate reducing equivalents for electron transport</p> Signup and view all the answers

    What is the irreversible reaction in the TCA cycle associated with a rate-limiting step?

    <p>Oxidative decarboxylation of isocitrate</p> Signup and view all the answers

    Glucose has a caloric value of ______ kcal/mol.

    <p>684</p> Signup and view all the answers

    High-energy compounds are also known as ______ compounds.

    <p>energy-rich</p> Signup and view all the answers

    The free energy change for palmitate is ______ kJ/mol.

    <p>-9,987</p> Signup and view all the answers

    ATP has a standard free energy change (△G) of approximately ______ kcal/mol.

    <p>-7.3</p> Signup and view all the answers

    High-energy bonds are found in the majority of ______ compounds.

    <p>high-energy</p> Signup and view all the answers

    The enzyme α-ketoglutarate dehydrogenase is activated by the availability of ______.

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

    The overall products of the TCA cycle are ______ and ATP.

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

    Mutations in TCA cycle enzymes may result in various kinds of ______.

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

    Neurodegenerative diseases like Alzheimer’s Disease are linked to reduced TCA cycle activity leading to energy ______ in neurons.

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

    Inhibitors of the TCA cycle include ______ and ATP.

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

    Glycolysis occurs in the ______.

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

    During pyruvate oxidation, each pyruvate is converted to ______.

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

    The TCA cycle takes place in the ______.

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

    In oxidative phosphorylation, electrons from NADH and FADH2 are transferred through the ______.

    <p>electron transport chain</p> Signup and view all the answers

    The maximum ATP yield from complete glucose oxidation has a Gibbs free energy change of ∆G0' = ______.

    <p>-2,864 kJ/mol</p> Signup and view all the answers

    Biological oxidations are essential for generating ______, the energy currency of the cell.

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

    An oxidizing agent is a substance that ______ an electron in a redox reaction.

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

    The loss of electrons during a reaction is termed ______.

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

    In redox chemistry, the substance that donates an electron is called a ______.

    <p>reducing agent</p> Signup and view all the answers

    Free energy that is available for useful work is referred to as ______ free energy.

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

    Pyruvate oxidation links glycolysis to the ______ cycle.

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

    Pyruvate is produced during ______, the process of breaking down glucose.

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

    The conversion of pyruvate into Acetyl-CoA occurs in the mitochondrial ______.

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

    Acetyl-CoA is involved in the tricarboxylic acid (TCA) cycle for ______ production.

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

    Acetyl-CoA is produced by the breakdown of glucose, fatty acids, and ______ acids.

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

    In anaerobic conditions, pyruvate can be reduced to ______.

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

    Excess Acetyl-CoA can be converted into ketone bodies in the ______.

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

    The TCA cycle produces ______ and FADH₂ for ATP synthesis in the electron transport chain.

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

    The process of pyruvate oxidation involves an enzyme complex known as ______ dehydrogenase.

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

    Acetyl-CoA serves as a precursor for the biosynthesis of ______ acids.

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

    Anaplerotic reactions are important for replenishing ______ intermediates in the TCA cycle.

    <p>four- or five-carbon</p> Signup and view all the answers

    Pyruvate acts as a metabolic hub linking carbohydrate metabolism to fat and ______ metabolism.

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

    The enzyme ______ converts pyruvate and CO2 to oxaloacetate.

    <p>pyruvate carboxylase</p> Signup and view all the answers

    Citrate synthase catalyzes the first step of the ______ cycle.

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

    The TCA cycle is considered an ______ pathway as it serves both catabolic and anabolic processes.

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

    Feedback mechanisms in the TCA cycle ensure homeostasis based on cellular ______ levels.

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

    Acetyl-CoA from fat metabolism enters the TCA cycle, linking ______ and carbohydrate metabolism.

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

    Removal of carbon waste in the TCA cycle occurs through the production of ______.

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

    Study Notes

    Mitochondria

    • Act as the central hub for energy production in eukaryotic cells
    • Structure:
      • Outer Membrane: Smooth, permeable, contains porins for small molecule and ion transport
      • Inner Membrane: Folded into cristae, contains proteins for the electron transport chain and ATP synthesis, impermeable to most ions and molecules
      • Intermembrane Space: Between outer and inner membranes, crucial for proton gradient in ATP production
      • Mitochondrial Matrix: Enclosed by inner membrane, contains enzymes for the TCA cycle, mtDNA, ribosomes, and metabolic enzymes. Site of key metabolic processes, including the TCA cycle and fatty acid oxidation.

    Cellular Respiration

    • Process by which cells convert nutrients to energy (ATP) using oxygen
    • Occurs primarily in mitochondria of eukaryotic cells
    • Provides ATP, the energy currency for cellular activities like muscle contraction, nerve impulse transmission, and biosynthesis
    • Integrates metabolic pathways, linking catabolism and anabolism
    • Utilizes oxygen efficiently, allowing for high-energy yield compared to anaerobic processes
    • Regulates energy balance and metabolic homeostasis in response to dietary intake and energy demands

    Key Stages of Cellular Respiration

    • Glycolysis: Occurs in cytoplasm, breaks down glucose into two pyruvate molecules
    • Pyruvate Oxidation: Occurs in the mitochondrial matrix, converts pyruvate to Acetyl-CoA, producing NADH and releasing CO2
    • TCA Cycle (Krebs Cycle): Occurs in the mitochondrial matrix, oxidizes Acetyl-CoA, generating NADH, FADH2, and GTP
    • Oxidative Phosphorylation: Occurs on the inner mitochondrial membrane, electrons from NADH and FADH2 are transferred through the electron transport chain, creating a proton gradient that drives ATP synthesis

    Biological Oxidations

    • Fundamental process in cellular respiration, facilitating efficient energy production
    • Cells convert nutrients into energy through electron transfer
    • Oxidation: Loss of electrons during a reaction
    • Reducing agent: Donates electrons, becoming oxidized
    • Oxidizing agent: Gains electrons, becoming reduced
    • Enzymes and coenzymes facilitate biological oxidations
    • Importance: Essential for ATP generation, balancing energy production and consumption, and influencing metabolic pathways

    Oxidation-reduction Reactions (Redox)

    • Chemical reactions involving electron transfer between species
    • Oxidation: Loss of electrons
    • Reduction: Gain of electrons
    • Integrated with metabolism for energy balance and cellular activities, playing crucial roles in energy production, metabolic regulation, and biosynthesis

    Gibbs Free Energy (G)

    • Portion of total energy available for useful work
    • ∆G: Change in free energy
    • During complete glucose oxidation, a large amount of energy is made available

    Enzyme and Coenzyme in Biological Oxidation

    • Enzymes: Proteins that act as biological catalysts, accelerating reactions, including oxidoreductases
      • Oxidases, Dehydrogenases, Hydroperoxidases, Oxygenases
    • Coenzymes: Organic compounds required by enzymes for catalytic activity
      • Nicotinamide adenine dinucleotide (NAD+), Nicotinamide adenine dinucleotide phosphate (NADP+), Flavin mononucleotide (FMN), Flavin adenine dinucleotide (FAD)

    NAD+ and NADPH in Catabolism and Anabolism

    • Catabolic reactions are generally oxidative, reducing substrates (carbohydrates, fats, and proteins)
    • NAD+ is reduced to NADH during catabolism
    • Anabolism is reductive, using NADPH, a phosphorylated form of NADH, to convert small molecules into complex ones

    Pyruvate Dehydrogenase Complex (PDC)

    • Enzyme complex that catalyzes the conversion of pyruvate to Acetyl-CoA
    • Composed of three enzymes: Pyruvate dehydrogenase (E1), Dihydrolipoyl transacetylase (E2), Dihydrolipoyl dehydrogenase (E3)
    • Binds to three cofactors: Thiamin pyrophosphate (TPP), Lipoamide, Flavin adenine dinucleotide (FAD)
    • Regulated by both reactants/products and enzymes
      • Activators: NAD+, CoA
      • Inhibitors: Acetyl-CoA and NADH
      • Pyruvate dehydrogenase kinase (inhibits) and pyruvate dehydrogenase phosphatase (activates)

    TCA Cycle (Krebs Cycle)

    • Occurs in the mitochondrial matrix
    • Acetyl-CoA produced from catabolic pathways is completely oxidized to CO2
    • Converts NAD+ and FAD into NADH and FADH2, which are further oxidized by the electron transport chain to generate ATP
    • Key regulatory point for metabolism

    Reactions of TCA Cycle

    • Step 1: Condensation of oxaloacetate with acetyl-CoA to form citrate. Catalyzed by citrate synthase. Irreversible, a key regulatory point.
    • Step 2: Isomerization of citrate to isocitrate. Catalyzed by aconitase. Reversible.
    • Step 3: First oxidative decarboxylation of isocitrate to α-ketoglutarate. Catalyzed by isocitrate dehydrogenase. Irreversible, rate-limiting step.
    • Step 4: Second oxidative decarboxylation of α-ketoglutarate to succinyl-CoA. Catalyzed by α-ketoglutarate dehydrogenase. Irreversible.
    • Step 5: Succinyl-CoA is converted to succinate, producing GTP. Catalyzed by succinyl-CoA synthetase. Reversible.
    • Step 6: Oxidation of succinate to fumarate, reducing FAD to FADH2. Catalyzed by succinate dehydrogenase. Reversible.
    • Step 7: Hydration of fumarate to malate. Catalyzed by fumarase. Reversible.
    • Step 8: Oxidation of malate to oxaloacetate, reducing NAD+ to NADH. Catalyzed by malate dehydrogenase. Reversible.

    Summary of TCA Cycle

    • For each acetyl-CoA molecule:
      • Two CO2 molecules
      • Three NADH molecules
      • One FADH2 molecule
      • One GTP/ATP molecule

    Roles of TCA Cycle

    • Energy Production: Generates ATP through oxidation of Acetyl-CoA
    • Biosynthesis: Provides intermediates for anabolic pathways
    • Metabolic Regulation: Links to other pathways, contributing to metabolic homeostasis

    TCA Cycle: Energy Production and Intermediates

    • Amphibolic Pathway: The TCA cycle plays a dual role in metabolism, serving both catabolic (breaking down) and anabolic (building up) processes.
    • Catabolic Function: It breaks down carbohydrates to generate energy.
    • Anabolic Function: It provides precursors for biosynthesis, such as amino acids and nucleotides.

    Metabolic Intermediates (Metabolic Hub)

    • Biosynthesis Sources: The cycle supplies intermediates for pathways involved in the creation of amino acids and nucleotides.
    • Anaplerotic Reactions: These reactions replenish the intermediates of the TCA cycle that are removed for other metabolic processes, primarily by converting pyruvate to oxaloacetate.
    • Maintaining the Cycle: Anaplerotic reactions are essential for ensuring the continuous operation of the TCA cycle by providing a steady supply of oxaloacetate, a critical four-carbon intermediate.

    Linking Pathways

    • Integration with Glycolysis: The TCA cycle connects carbohydrate metabolism to energy production by accepting pyruvate, a product of glycolysis.
    • Fatty Acid Oxidation: Acetyl-CoA, derived from the breakdown of fatty acids, enters the TCA cycle, integrating lipid and carbohydrate metabolism.

    Regulation of Metabolism

    • Substrate Availability: Regulation of the TCA cycle is influenced by the availability of substrates, such as pyruvate and acetyl-CoA.
    • Energy Needs: The cycle is sensitive to the cells' energy demands, responding to levels of ATP, ADP, and NADH.
    • Feedback Mechanisms: Feedback mechanisms ensure that the activity of the TCA cycle is tightly controlled to maintain cellular energy homeostasis.

    Removal of Metabolic Wastes

    • CO₂ Production: The TCA cycle produces carbon dioxide, facilitating the removal of carbon waste from the body and maintaining acid-base balance.

    Anaplerotic Reactions

    • Oxaloacetate Replenishment: While oxaloacetate is regenerated during the TCA cycle, metabolic pathways can deplete it.
    • Four-Carbon Acids: Anaplerotic reactions replenish the TCA cycle with four-carbon acids to ensure its continued function.
    • Pyruvate Carboxylase: The enzyme pyruvate carboxylase plays a crucial role in anaplerotic reactions by converting pyruvate and carbon dioxide into oxaloacetate.

    Regulation of TCA Cycle Activity

    • Enzymes: The TCA cycle is regulated by the activity of several key enzymes, including:
      • Pyruvate dehydrogenase: Regulates the production of acetyl-CoA.
      • Citrate synthase: Controls the first step of the cycle.
      • Isocitrate dehydrogenase: Regulates the third step of the cycle.
      • α-ketoglutarate dehydrogenase: Controls the fourth step of the cycle.

    Biological Oxidations

    • Cellular Respiration: Biological Oxidations are central to energy production in living organisms.
    • Electron Transfer: These reactions involve the transfer of electrons, resulting in the oxidation of substrates.
    • Energy Release: The chemical systems transition from a higher to a lower energy level, releasing energy.
    • ATP Formation: This released energy is converted into chemical energy through ATP (adenosine triphosphate) formation.
    • Enzymes and Coenzymes: Biological Oxidations are facilitated by enzymes and coenzymes.

    Importance of Biological Oxidations

    • ATP Production: Essential for generating ATP, the cell's energy currency.
    • Metabolic Regulation: Helps balance energy production and consumption, influencing various metabolic pathways.

    Oxidation-Reduction Reactions (Redox)

    • Electron Transfer: A type of chemical reaction involving the transfer of electrons between two species.
    • Reduced and Oxidized Halves: Reactions involve a reduced half and an oxidized half.
    • Metabolic Integration: Redox reactions are critical for energy balance, supporting cellular activities like energy production, metabolic regulation, and biosynthesis.

    Oxidation

    • Electron Loss: A molecule, atom, or ion losing electrons during a reaction.
    • Oxidizing Agent: Gains or accepts electrons in a redox reaction.

    Reduction

    • Electron Gain: A molecule, atom, or ion accepting electrons during a reaction.
    • Reducing Agent: Donates electrons in a redox reaction.

    Free Energy

    • Gibbs Free Energy (G): Represents the portion of total energy readily available for useful work.
    • ∆G: Change in Free Energy.
    • Complete Glucose Oxidation: Produces a substantial amount of energy, with a maximum ATP yield of -2,864 kJ/mol.
    • Lipid Caloric Value: Lipids, like palmitate, have a calorific value nearly three times greater than carbohydrates and proteins.

    High-Energy Compounds and Bonds

    • High-Energy Compounds: Their hydrolysis products are more stable than the original compound, releasing energy.
    • Energy-Rich Compounds: Produce free energy greater than or equal to ATP upon hydrolysis.
    • Phosphate Groups: Most high-energy compounds contain phosphate groups.
    • High-Energy Bonds: Present in high-energy compounds, producing energy during hydrolysis.

    Pyruvate Oxidation in Cellular Respiration

    • Pyruvate Oxidation: Key step linking glycolysis to the TCA cycle, converting pyruvate to Acetyl-CoA.
    • Mitochondrial Matrix: Takes place in the mitochondrial matrix.
    • Complete Glucose Oxidation: Enables complete oxidation of glucose.
    • ATP production: Essential for ATP production and overall cellular metabolism.

    Acetyl Coenzyme A (Acetyl-CoA)

    • Key Metabolic Intermediate: Involved in a wide range of metabolic pathways.
    • Acetyl Group: Composed of an acetyl group (CH₃CO−) linked to coenzyme A.
    • Glucose, Fatty Acids, and Amino Acids: Produced during the breakdown of these molecules.
    • Energy Production: Critical for the TCA cycle, generating ATP.
    • Biosynthesis: Precursor for biosynthesis of fatty acids, cholesterol, and ketone bodies.
    • Amino Acid Metabolism: Participates in the metabolism of specific amino acids.

    Pyruvate

    • Conjugate Base of Pyruvic Acid: A key intermediate in various biological processes.
    • Chemical Formula: C₃H₄O₃
    • Glycolysis End Product: Produced during glycolysis, representing the end product of glucose breakdown.
    • Amino Acid Degradation: Also formed by the degradation of amino acids.

    Pyruvate Function

    • Energy Production: Converted to Acetyl-CoA for entry into the TCA cycle.
    • Anaerobic Conditions: Reduced to lactate in the absence of oxygen (anaerobic conditions).
    • Metabolic Hub: Connects carbohydrate metabolism to fat and protein metabolism.

    Pyruvate Oxidation

    • Definition: The conversion of pyruvate into Acetyl-CoA, bridging glycolysis to the TCA cycle.
    • Location: Occurs in the mitochondrial matrix of eukaryotic cells.
    • Three Steps:
      • Decarboxylation: Pyruvate loses a carbon dioxide molecule (CO2).
      • Oxidation: Pyruvate loses electrons which are picked up by NAD+ to form NADH.
      • Acetyl-CoA Formation: The remaining two-carbon unit combines with Coenzyme A to form Acetyl-CoA.

    Pyruvate Oxidation and its Importance

    • Energy Production: Generates NADH and FADH2 for ATP synthesis using the electron transport chain.
    • Metabolic Intermediates: Contributes to the biosynthesis of amino acids and nucleotides.
    • Metabolic Hub: Connects carbohydrate metabolism to energy production.
    • Regulation of Metabolism: Sensitive to energy needs.
    • Metabolic Waste Removal: CO2 Production facilitates waste removal, maintaining acid-base balance.

    TCA Cycle (Krebs Cycle or Citric Acid Cycle)

    • Mitochondrial Matrix: Occurs in the mitochondrial matrix.
    • Acetyl-CoA Oxidation: Completes the oxidation of Acetyl-CoA, generating key energy carriers.
    • Energy Carriers: Produces NADH, FADH2, and GTP (or ATP).
    • Amphibolic Pathway: Serves in both catabolism (breakdown) and anabolism (synthesis) pathways.

    Roles of TCA Cycle

    • Catabolism and Anabolism: Central to both breakdown of carbohydrates (catabolism) and synthesis of essential molecules (anabolism).

    Anaplerotic Reactions

    • Intermediates Replenishment: Reactions that replenish the TCA cycle intermediates to maintain its function.
    • Oxaloacetate Regeneration: Essential as oxaloacetate is regenerated throughout the cycle.
    • Four-Carbon Acids: Provides a source of four-carbon acids to replace lost oxaloacetate.
    • Pyruvate Carboxylase: The key enzyme in anaplerotic reactions, converting pyruvate and CO2 to oxaloacetate.

    Regulation of TCA Cycle Activity

    • Enzymes: Key enzymes involved in the regulation.
      • Pyruvate Dehydrogenase: Produces Acetyl-CoA, a key starting point.
      • Citrate Synthase: First step of the cycle.
      • Isocitrate Dehydrogenase: Third step of the cycle.
      • α-Ketoglutarate Dehydrogenase: Fourth step of the cycle.
    • Substrate Availability: The presence of substrates (e.g., Acetyl-CoA, oxaloacetate) promotes cycle activation.
    • Product Accumulation: Product buildup (e.g., ATP) inhibits the cycle.
    • NADH and ATP: Inhibit all regulated enzymes.
    • NAD+ and AMP: Activate all regulated enzymes.

    Diseases Associated with TCA Cycle

    • Mitochondrial Disorders: Genetic defects in mitochondrial function can impair the TCA cycle, leading to energy production failure.
    • Cancer: Altered TCA cycle activity, often linked to mutations in key enzymes, is observed in many cancers.
    • Metabolic Disorders: Impaired TCA cycle activity contributes to lipid accumulation (hyperlipidemia) and diabetes.
    • Neurodegenerative Diseases: Reduced TCA cycle activity is linked to energy deficits in neurons, contributing to neurodegeneration.

    TCA Cycle Mutations and Diseases

    • Mutations in TCA cycle enzymes: Can lead to various cancers.
    • Potential Treatments: Pharmacological and genetic therapeutic approaches offer potential treatment options.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Lecture 4: Metabolism and Energy I: Tricarboxylic Acid (TCA) Cycle PDF

    Description

    Explore the vital functions of mitochondria in eukaryotic cells and their role in cellular respiration. Understand the structure of mitochondria and the processes involved in ATP production and energy conversion. Test your knowledge on how these organelles support life at the cellular level.

    More Like This

    Mitochondria and Cellular Respiration Quiz
    10 questions

    Mitochondria and Cellular Respiration Quiz

    FelicitousZebra avatar
    FelicitousZebra
    Mitochondria: Structure, Function, and Diseases
    12 questions

    Mitochondria: Structure, Function, and Diseases

    InexpensiveFreesia avatar
    InexpensiveFreesia
    Mitochondria Structure and Function Quiz
    12 questions

    Mitochondria Structure and Function Quiz

    InexpensiveFreesia avatar
    InexpensiveFreesia
    Cellular Respiration Processes Quiz
    16 questions

    Cellular Respiration Processes Quiz

    BeneficialSupernova avatar
    BeneficialSupernova
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser