Bioenergetics and Free Energy Change
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Questions and Answers

What is the primary structural feature of glycogen?

  • Linear chain only
  • Unbranched with a central protein
  • Completely symmetrical
  • Branched-chain (correct)

    • The liver only uses glycogen for its own energy needs.

    False

    What molecule needs to be activated by UDP before being integrated into glycogen?

    Glucose 1-P

    The synthesis of ribose 5-phosphate is a product of the __________ pathway.

    <p>Pentose Phosphate</p> Signup and view all the answers

    Which of the following is a function of glycogen in skeletal muscle?

    <p>Serves as a local and fast resource for ATP</p> Signup and view all the answers

    Match the following components with their associated functions:

    <p>Glucose 6-P = Intermediate for glycolysis Ribulose 5-P = Nucleotide synthesis NADPH = Reducing agent in biosynthesis UDP-glucose = Activated form of glucose for glycogen synthesis</p> Signup and view all the answers

    Which type of reaction in the Pentose Phosphate Pathway is irreversible?

    <p>Oxidative reactions</p> Signup and view all the answers

    What is the center protein around which glycogen is built?

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

    What is the primary function of NADH and FADH2 in the electron transport chain?

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

    One molecule of NADH yields approximately 2.5 ATP when fully oxidized.

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

    What is the total ATP yield from one mole of glucose after glycolysis and the TCA cycle?

    <p>36 or 38 ATP</p> Signup and view all the answers

    The conversion of pyruvate to acetyl-CoA occurs during the ______ stage.

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

    Match the following pathways with their descriptions:

    <p>Glycolysis = Breakdown of glucose to pyruvate Gluconeogenesis = Synthesis of glucose from non-carbohydrate sources Pentose Phosphate Pathway = Generating ribose-5-phosphate for nucleotide synthesis Glycogen Degradation = Mobilization of glucose from stored glycogen</p> Signup and view all the answers

    Which shuttle converts NADH into FADH2 within the mitochondria?

    <p>Glycerol 3-phosphate Shuttle</p> Signup and view all the answers

    The body relies solely on dietary intake for a stable blood glucose level.

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

    Name one of the end products of glycolysis.

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

    After glycolysis, pyruvate is converted to ______ before entering the TCA cycle.

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

    From where can blood glucose be obtained?

    <p>Diet, gluconeogenesis, and glycogen degradation</p> Signup and view all the answers

    What is the main purpose of bioenergetics?

    <p>To transfer and utilize energy in biological systems</p> Signup and view all the answers

    A negative ΔG indicates a spontaneous reaction.

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

    What are the two main types of ATP production?

    <p>Substrate-level phosphorylation and oxidative phosphorylation.</p> Signup and view all the answers

    The __________ cycle is also known as the Krebs cycle.

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

    Match the following metabolic pathways with their functions:

    <p>Glycolysis = Energy production and pyruvate formation Glycogenesis = Synthesis of glycogen from glucose Glycogenolysis = Breakdown of glycogen to glucose TCA Cycle = Harvesting high-energy electrons</p> Signup and view all the answers

    Which molecule is commonly referred to as the energy currency of the cell?

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

    The electron transport chain involves the reduction of oxygen to water.

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

    What is the end product of glycolysis?

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

    NADH and FADH2 serve as electron __________ in ATP synthesis.

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

    Match the following ATP production methods with their descriptions:

    <p>Substrate-level phosphorylation = Direct synthesis of ATP from ADP Oxidative phosphorylation = ATP production coupled with electron transport Fermentation = Anaerobic process that regenerates NAD+</p> Signup and view all the answers

    Which pathway provides intermediates for the synthesis of amino acids, lipids, and carbohydrates?

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

    Glycogenesis is the process of breaking down glycogen into glucose.

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

    What happens to pyruvate in the presence of oxygen?

    <p>It is converted to Acetyl-CoA and enters the TCA cycle.</p> Signup and view all the answers

    The __________ phosphate pathway produces ribose-5-phosphate.

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

    Match each molecule with its energy contribution:

    <p>ATP = Immediate energy currency ADP = Lower energy state than ATP NADH = High-energy electron carrier FADH2 = Another high-energy electron carrier</p> Signup and view all the answers

    Study Notes

    Bioenergetics

    • Bioenergetics is the transfer and utilization of energy in biological systems
    • Bioenergetics predicts if a process is possible, while kinetics measures the reaction rate
    • Enzymes cannot initiate a chemical reaction on their own
    • Molecules and reactions can be either exergonic or endergonic

    Free Energy Change (ΔG)

    • ΔG = final energy - initial energy
    • A negative ΔG indicates a spontaneous reaction (exergonic) that releases energy
    • A positive ΔG indicates a nonspontaneous reaction (endergonic) that requires energy input

    ATP Production

    • ATP is the primary energy currency for cells
    • Substrate-level phosphorylation
    • Oxidative phosphorylation

    Carbohydrate Metabolism

    • Glucose is a critical energy source
    • Glycolysis, glycogenolysis, and gluconeogenesis are key pathways for glucose metabolism
    • Glycogen is used for glucose storage

    Hormonal Regulation of Glycolysis

    • Hormones, like insulin and glucagon, regulate glucose uptake and utilization
    • Insulin typically increases glycolysis, while glucagon likely decreases it

    Glycolysis - NAD+ Regeneration

    • Glycolysis requires NAD+ to occur
    • Fermentation produces NAD+ when oxygen is absent

    TCA Cycle

    • The TCA cycle is crucial to capture high-energy electrons
    • The cycle's purpose is to harvest high-energy electrons from carbon fuels
    • Electrons are captured as NADH and FADH2 for ATP production

    Oxidative Phosphorylation and ETC

    • The electron transport chain (ETC) is involved with oxidative phosphorylation
    • NADH and FADH2 carry high-energy electrons, resulting in ATP production

    Electron Transport Chain

    • Electrons carried by NADH and FADH2 are captured by the system
    • Oxygen is reduced to water
    • ETC complexes pump H+ to outer membranes
    • Positive charge out of the membrane produces a flow into the matrix
    • ATP is synthesised

    ETC - Overall Picture

    • NADH enters from Complex I, FADH2 from Complex II
    • One NADH pumps three protons
    • One FADH2 pumps two protons

    Energy Gained from 1 mol Glucose

    • Glycolysis produces 2 ATP and 2 NADH
    • Pyruvate yields 2 NADH in the cytoplasm
    • Acetyl-CoA yields 6 NADH and 2 FADH2
    • The total number of ATPs produced from a mol of glucose depends on the shuttle systems used to transport NADH from the cytoplasm to the mitochondria

    Transfer of Cytoplasmic NADH to Mitochondria

    • Malate Aspartate Shuttle and Glycerol 3-phosphate shuttle are used to transport NADH into the mitochondrial
    • NADH can't enter the mitochondria directly

    Pentose Phosphate Pathway

    • It produces NADPH and ribose 5-phosphate
    • The pathway has oxidative and non-oxidative reactions
    • Ribose 5-phosphate is used in nucleotide synthesis.

    Glycogen

    • A storage form of glucose in animals
    • Glycogen is predominantly stored in the liver and muscle
    • Glycogen degradation serves as a critical energy source
    • The synthesis involves glucose 1-P activation with UDP
    • Glycogen degradation occurs by cleaving glucose molecules

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    Bioenergetics and Carbohydrate Metabolism PDF

    Description

    This quiz covers key concepts in bioenergetics, including energy transfer in biological systems and the role of free energy change (ΔG) in chemical reactions. It also addresses ATP production, carbohydrate metabolism, and the hormonal regulation of glycolysis. Test your understanding of these essential biochemical processes.

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