Carbs 2
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Carbs 2

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Questions and Answers

Which transporter can transport glucose against its concentration gradient?

  • SGLT-1 (correct)
  • GLUT
  • Na+/H+ antiporter
  • Na+/K+-ATPase

    • What is the central ATP-producing pathway in most organisms?

  • Glycolysis (correct)
  • Citric acid cycle
  • Gluconeogenesis
  • Electron transport chain

    • Which process involves the reduction of pyruvate to lactate in eukaryotic cells under anaerobic conditions?

  • Citric acid cycle
  • Gluconeogenesis
  • Fermentation (correct)
  • Oxidative phosphorylation

    • What is the energy-requiring enzyme that maintains the Na⁺ gradient to facilitate SGLT cotransport?

    <p>Na⁺K⁺-ATPase</p> Signup and view all the answers

    Where does glycolysis primarily occur in most organisms?

    <p>Cell cytosol</p> Signup and view all the answers

    Which process does not depend on oxygen for ATP production?

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

    What is the primary fate of ACETYL-COA in the mitochondria?

    <p>It is coupled with OXALOACETATE and oxidized to CO2, H2O, and ATP.</p> Signup and view all the answers

    Which of the following is NOT a way that metabolism is regulated?

    <p>Neurotransmitter signaling</p> Signup and view all the answers

    What is the primary purpose of the GLUT transporters for glucose?

    <p>To passively transport glucose into cells along the concentration gradient</p> Signup and view all the answers

    Which of the following cellular processes is NOT driven by the catabolism of carbohydrates?

    <p>Fatty acid synthesis</p> Signup and view all the answers

    Which type of GLUT transporter is responsive to insulin?

    <p>GLUT-4</p> Signup and view all the answers

    How do intracellular signals coordinate metabolic functions?

    <p>All of the above</p> Signup and view all the answers

    What is the primary purpose of fermentation in the body?

    <p>To produce lactate or ethanol</p> Signup and view all the answers

    Which of the following tissues or cell types is MOST likely to rely on anaerobic glycolysis for energy production?

    <p>Erythrocytes (red blood cells) which lack mitochondria</p> Signup and view all the answers

    What is the primary fate of lactate produced during anaerobic glycolysis?

    <p>Lactate is converted to glucose through gluconeogenesis</p> Signup and view all the answers

    In the presence of oxygen, what happens to the pyruvate produced during glycolysis?

    <p>Pyruvate is converted to acetyl-CoA and enters the TCA cycle</p> Signup and view all the answers

    What is the primary purpose of the electron transport chain (ETC) in aerobic respiration?

    <p>To convert NADH and FADH2 into ATP through oxidative phosphorylation</p> Signup and view all the answers

    Which of the following is the MOST important factor in regulating glucose metabolism?

    <p>The expression of glucose transporter proteins (GLUT)</p> Signup and view all the answers

    In metabolism, which type of pathway involves the breakdown of molecules into smaller units that can be oxidized to release energy?

    <p>Catabolic pathways</p> Signup and view all the answers

    What is the primary purpose of anabolic pathways in cellular metabolism?

    <p>Form more complex molecules</p> Signup and view all the answers

    During catabolism for ATP production, what is the primary fate of acetyl-CoA in the mitochondria?

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

    Which term best describes pathways in metabolism that end up with the regeneration of a component?

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

    What is the sum of all chemical reactions occurring in a cell, a tissue, or a body known as?

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

    Which of the following is the primary function of the TCA cycle in cellular metabolism?

    <p>To provide energy-rich molecules for the oxidative phosphorylation process</p> Signup and view all the answers

    What is the primary role of the electron transport chain (ETC) in aerobic respiration?

    <p>To generate ATP through the process of oxidative phosphorylation</p> Signup and view all the answers

    Which of the following is the MOST important factor in regulating glucose metabolism?

    <p>The concentration of insulin in the bloodstream</p> Signup and view all the answers

    What is the primary fate of the pyruvate produced during glycolysis in the presence of oxygen?

    <p>It is transported to the mitochondria and enters the TCA cycle</p> Signup and view all the answers

    Which of the following is a key regulatory mechanism for coordinating metabolic functions in the body?

    <p>The concentration of hormones like insulin and glucagon</p> Signup and view all the answers

    What is the primary purpose of the GLUT transporters for glucose in the body?

    <p>To facilitate the diffusion of glucose down its concentration gradient</p> Signup and view all the answers

    What is the primary function of the ACETYL-COA molecule in cellular metabolism?

    <p>It is oxidized in the mitochondria to produce ATP through the electron transport chain.</p> Signup and view all the answers

    Which of the following is the MOST important regulatory mechanism for coordinating cellular metabolism?

    <p>Availability of nutrients and substrates for metabolic pathways.</p> Signup and view all the answers

    What is the primary fate of lactate produced during anaerobic glycolysis in most tissues?

    <p>It is transported to the liver and converted back to glucose via gluconeogenesis.</p> Signup and view all the answers

    What is the primary purpose of the electron transport chain (ETC) in aerobic respiration?

    <p>To generate ATP through the process of oxidative phosphorylation.</p> Signup and view all the answers

    Which of the following cellular processes is NOT driven by the catabolism of carbohydrates?

    <p>Gluconeogenesis to synthesize glucose from non-carbohydrate precursors.</p> Signup and view all the answers

    In which process does the conversion of pyruvate to acetyl-CoA occur?

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

    Which of the following pathways is primarily responsible for the production of ATP in the presence of oxygen?

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

    What is the primary fate of acetyl-CoA produced during the oxidative decarboxylation of pyruvate?

    <p>It is used as a substrate for the citric acid cycle</p> Signup and view all the answers

    What is the primary purpose of the citric acid cycle (Krebs cycle)?

    <p>To oxidize acetyl-CoA and generate reducing equivalents</p> Signup and view all the answers

    Which of the following processes is primarily involved in the regulation of glucose metabolism?

    <p>All of the above</p> Signup and view all the answers

    What is the primary regulator of glycolysis and the entry of pyruvate into the mitochondria?

    <p>Availability of oxygen</p> Signup and view all the answers

    Which of the following pathways is responsible for the complete oxidation of glucose under aerobic conditions?

    <p>Glycolysis followed by the citric acid cycle and electron transport chain</p> Signup and view all the answers

    What is the primary fate of acetyl-CoA produced from the oxidation of pyruvate in the mitochondria?

    <p>It enters the citric acid cycle</p> Signup and view all the answers

    Which of the following processes is an anabolic pathway that can utilize the products of glucose catabolism?

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

    In which tissue or cell type would anaerobic glycolysis be most prevalent?

    <p>Skeletal muscle (white fibers)</p> Signup and view all the answers

    Which of the following accurately describes the regulation of glucose metabolism?

    <p>Glucose metabolism is regulated by a combination of factors, including oxygen availability, energy demand, and hormonal signals</p> Signup and view all the answers

    Which of the following statements about glycolysis is correct?

    <p>It is a highly regulated process to meet the cell's ATP needs</p> Signup and view all the answers

    What is the primary role of the Na⁺/K⁺-ATPase enzyme?

    <p>To maintain the Na⁺ gradient for SGLT cotransport</p> Signup and view all the answers

    Under anaerobic conditions, what is the fate of the NADH produced during glycolysis in eukaryotic cells?

    <p>It is used to reduce pyruvate to lactate</p> Signup and view all the answers

    Which of the following pathways is primarily responsible for the oxidation of acetyl-CoA?

    <p>The Krebs cycle</p> Signup and view all the answers

    Which of the following statements about GLUT transporters is correct?

    <p>They facilitate glucose transport across cell membranes</p> Signup and view all the answers

    What is the primary purpose of fermentation in the body?

    <p>To produce ATP in the absence of oxygen</p> Signup and view all the answers

    Which of the following is NOT a product of glycolysis?

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

    In the presence of oxygen, what is the primary fate of the pyruvate produced during glycolysis?

    <p>It is oxidized to acetyl-CoA</p> Signup and view all the answers

    Which of the following statements about the SGLT-1 transporter is correct?

    <p>It can transport glucose against its concentration gradient</p> Signup and view all the answers

    Study Notes

    Glucose Transport

    • Glucose cannot diffuse into cells, it must be transported by transporters
    • Two types of glucose transporters:
      • GLUT transporters: passive system, do not require ATP, highly tissue specific, some are insulin responsive (GLUT 4)
      • SGLT-1 transporter: Na⁺-dependent cotransporter, can transport glucose against its concentration gradient, ATP-dependent antiport system Na+/K+- ATPase (pump)

    Glycolysis

    • Central ATP-producing pathway, takes place in cell cytosol in all tissues
    • Highly regulated process, just enough glucose is metabolized to meet the cell’s need for ATP
    • Does not depend on oxygen
    • Net gain: 2 pyruvate + 2 NADH + 2 ATP
    • Can be aerobic or anaerobic, red blood cells and muscle take advantage of anaerobic glycolysis

    Anaerobic Glycolysis

    • NADH unloads H⁺ on pyruvate, reducing it to lactate (in eukaryotic cells)
    • Pyruvate reduced to lactate → Fermentation
    • Occurs in cells with low mitochondria density and poorly vascularized tissues (cornea, lens), skeletal muscle (white fibers), and cells lacking mitochondria (erythrocytes)
    • LDH=lactate dehydrogenase

    Aerobic Glycolysis

    • Pyruvate enters the mitochondria, converted into acetyl-CoA (link reaction)
    • NADH unloads H⁺ → ETC → regenerate NAD+
    • Approximately 42% of the energy of glucose is captured in the form of ATP
    • Remaining energy in glucose generates heat, aiding in the regulation of body temperature
    • Eventually, all energy derived from glucose oxidation is released as heat after ATP is used up

    Fates of Pyruvate

    • 4 possible fates:
      • Pyruvate reduction to lactate (fermentation)
      • Pyruvate reduction to ethanol (fermentation)
      • Oxidative decarboxylation to acetyl-CoA
      • Pyruvate carboxylation to oxaloacetate (OAA)

    Metabolism

    • Cellular reactions rarely occur in isolation, but as part of pathways that are multi-step sequences
    • One product serves as the substrate of the next reaction
    • Catabolic (degradative) pathways break down molecules into smaller units, anabolic (synthetic) pathways combine small molecules to form more complex molecules
    • Metabolism is the sum of all chemical reactions occurring in a cell, tissue, or body

    Regulation of Metabolism

    • Available nutrients, hormones, and neurotransmitters provide regulatory signals to coordinate metabolic functions
    • Intracellular communication: substrates availability, product inhibition, activators/inhibitors
    • Intercellular communication: direct cell surface contact, gap junctions, chemical signaling (hormones, neurotransmitters)
    • Second messenger system: signal transduction and cellular response (GPCR)

    TCA Cycle

    • Final pathway where carbohydrates, amino acids, and fatty acids converge
    • Energy provided by the TCA cycle is essential for most animals, including humans
    • TCA cycle location: mitochondria matrix
    • 2 carbons enter as acetyl-CoA, 2 leave as CO2
    • Aerobic because oxygen is the final electron acceptor (in ETC)

    Oxidative Phosphorylation

    • Energy-rich molecules (glucose, fatty acids) are metabolized by a series of oxidation reactions into ATP, CO2, and H2O
    • Reaction metabolic intermediates donate electrons to specific coenzymes: NAD+ & FAD → forms energy-rich reduced forms NADH & FADH2
    • NADH and FADH2 donate a pair of electrons to the Electron Transport Chain (ETC) → located on the mitochondria inner membrane
    • Oxidative Phosphorylation = Electron Transport Chain (ETC) + ATP synthesis

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    Carbohydrates 2 VP 2024 PDF

    Description

    Explore the SGLT-1 transporter, Na⁺-dependent cotransporter system, and the glycolysis process which is a key ATP-producing pathway. Learn about the ATP-dependent antiport system and Na+/K+-ATPase pump involved in maintaining the Na⁺ gradient for facilitating glucose transport.

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