Glycolysis Overview and Tissue Functions
32 Questions
2 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 main end product of glycolysis in the presence of oxygen?

  • Acetyl-CoA
  • Glucose
  • Pyruvate (correct)
  • Lactate

    • Which type of glycolysis occurs in the absence of oxygen?

  • Fermentative glycolysis
  • Anaerobic glycolysis (correct)
  • Aerobic glycolysis
  • Oxidative glycolysis

    • Which enzyme is responsible for converting fructose-6-phosphate to fructose-1,6-bisphosphate?

  • Phosphofructokinase (correct)
  • Aldolase
  • Glyceraldehyde-3-phosphate dehydrogenase
  • Hexokinase

    • In glycolysis, how many ATP molecules are net produced during anaerobic conditions?

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

    What key role does glycolysis serve in red blood cells (RBCs)?

    <p>Providing energy exclusively (C)</p> Signup and view all the answers

    Which compound is produced from glyceraldehyde-3-phosphate in glycolysis?

    <p>1,3-phosphoglycerate (D)</p> Signup and view all the answers

    What is one physiological importance of glycolysis in skeletal muscle tissue?

    <p>Energy source during high-intensity exercise (A)</p> Signup and view all the answers

    What is the primary end product of aerobic glycolysis?

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

    Which of the following statements is true regarding the ATP production from glucose during aerobic glycolysis?

    <p>Net gain of 8 ATP (A)</p> Signup and view all the answers

    Which enzyme is exclusively found in the liver that converts glucose?

    <p>Glucokinase (D)</p> Signup and view all the answers

    What is the fate of pyruvate in anaerobic glycolysis?

    <p>Converted to ethanol or lactate (C)</p> Signup and view all the answers

    How many ATP are generally produced from anaerobic glycolysis?

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

    What is a biological importance of glycolysis in relation to oxygenation of tissues?

    <p>Formation of 2,3 bisphosphoglycerate (A)</p> Signup and view all the answers

    Which statement about hexokinase is correct?

    <p>It is inhibited by glucose-6-phosphate. (C), It shows high affinity for glucose. (D)</p> Signup and view all the answers

    What is the role of NAD+ in glycolysis?

    <p>It acts as an electron acceptor. (A)</p> Signup and view all the answers

    Which glycolytic pathway yields the highest energy output?

    <p>Aerobic glycolysis (D)</p> Signup and view all the answers

    What process must occur to reoxidize NADH during fermentation?

    <p>Conversion of pyruvate to lactate (C)</p> Signup and view all the answers

    Which enzyme is responsible for the conversion of pyruvate to lactate?

    <p>Lactate Dehydrogenase (A)</p> Signup and view all the answers

    Which of the following statements about lactate is true?

    <p>Lactate can serve as a fuel source for some tissues (B)</p> Signup and view all the answers

    What role do astrocytes play in lactate metabolism?

    <p>They facilitate lactate transport to neurons (B)</p> Signup and view all the answers

    During intense exercise, what compound do skeletal muscles primarily produce?

    <p>Lactate (A)</p> Signup and view all the answers

    What is one possible fate of lactate after being released into the blood?

    <p>It can be converted back to pyruvate in other tissues (D)</p> Signup and view all the answers

    What is required for the Glyceraldehyde-3-phosphate Dehydrogenase reaction to occur?

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

    Which of the following statements best describes lactate's role in cellular metabolism?

    <p>Lactate is a mobile form of nutrient energy and may signal other cells (D)</p> Signup and view all the answers

    What is the role of Alcohol Dehydrogenase in pyruvate metabolism?

    <p>Converts NADH to NAD+ (C)</p> Signup and view all the answers

    Which of the following enzymes is NOT one of the key regulators of glycolysis?

    <p>Citrate lyase (A)</p> Signup and view all the answers

    How does high ATP concentration affect glycolysis?

    <p>Inhibits phosphofructokinase and pyruvate kinase (B)</p> Signup and view all the answers

    Which substrate is known to inhibit hexokinase?

    <p>Glucose-6-phosphate (B)</p> Signup and view all the answers

    During brief and intense exercise, which pathway do skeletal muscles primarily utilize?

    <p>Fermentation to lactate (B)</p> Signup and view all the answers

    What is the function of lactate in the body?

    <p>Mobilizes energy for other tissues (D)</p> Signup and view all the answers

    Which hormone stimulates the biosynthesis of glycolytic enzymes?

    <p>Insulin (B)</p> Signup and view all the answers

    What happens to lactate produced in exercising muscles after exercise?

    <p>It is transformed back into pyruvate (B)</p> Signup and view all the answers

    Flashcards

    Glycolysis

    The process of breaking down glucose to produce energy in the form of ATP.

    Aerobic Glycolysis

    Glycolysis that occurs in the presence of oxygen, producing more ATP than anaerobic glycolysis.

    Anaerobic Glycolysis

    Glycolysis that occurs without oxygen, producing less ATP than aerobic glycolysis, resulting in lactate.

    ATP Production (Glycolysis)

    The net gain of ATP from glucose in glycolysis varies depending on whether oxygen is present.

    Signup and view all the flashcards

    Substrate-Level Phosphorylation

    A metabolic reaction in which a phosphate group is directly transferred to ADP from another phosphorylated compound, to form ATP during glycolysis

    Signup and view all the flashcards

    Pyruvate

    The end product of glycolysis in the presence of oxygen

    Signup and view all the flashcards

    Lactate

    The end product of glycolysis in the absence of oxygen. It is produced from pyruvate through anaerobic respiration.

    Signup and view all the flashcards

    Specific tissue functions (glycolysis)

    Different tissues (e.g., red blood cells, muscle, liver, adipose) utilize glycolysis for various specialized purposes.

    Signup and view all the flashcards

    Lactate fermentation

    A metabolic pathway that converts pyruvate to lactate, reoxidizing NADH to NAD+.

    Signup and view all the flashcards

    NADH reoxidation

    The process of converting NADH back to NAD+ in the absence of oxygen.

    Signup and view all the flashcards

    Lactate Dehydrogenase

    Enzyme catalyzing the conversion between pyruvate and lactate.

    Signup and view all the flashcards

    Pyruvate to Lactate

    The reduction of pyruvate to lactate, coupled with NADH oxidation.

    Signup and view all the flashcards

    Fermentation

    Metabolic process that regenerates NAD+ by producing an organic end product from glucose.

    Signup and view all the flashcards

    Lactate Transport

    Movement of lactate across cell membranes, facilitated by carrier proteins.

    Signup and view all the flashcards

    Lactate as Fuel Source

    Lactate can be used by cardiac muscle and brain neurons as a source of energy.

    Signup and view all the flashcards

    Pyruvate to Ethanol Conversion

    Some organisms convert pyruvate to ethanol as a waste product during anaerobic metabolism.

    Signup and view all the flashcards

    Alcohol Dehydrogenase

    Enzyme that converts NADH to NAD+ during ethanol production.

    Signup and view all the flashcards

    Glycolysis Regulation

    Glycolysis, the breakdown of glucose, is controlled by key enzymes like hexokinase and phosphofructokinase.

    Signup and view all the flashcards

    Hormonal Regulation (Glycolysis)

    Hormones like insulin and adrenaline control glycolysis by influencing enzyme activity.

    Signup and view all the flashcards

    Substrate Regulation (Glycolysis)

    The levels of substrates like glucose-6-phosphate (G-6-P) and citrate affect glycolysis by regulating enzyme activity.

    Signup and view all the flashcards

    Energy Regulation in Glycolysis

    High levels of ATP inhibit glycolysis, while low levels (high ADP/AMP) stimulate it.

    Signup and view all the flashcards

    Lactate Formation (Skeletal Muscle)

    Skeletal muscles produce lactate during intense exercise due to rapid energy demands.

    Signup and view all the flashcards

    Lactate as Energy Source

    Lactate can be transported to other tissues and used as an energy source for processes like gluconeogenesis.

    Signup and view all the flashcards

    Glucokinase vs. Hexokinase

    Glucokinase is found in liver cells, is stimulated by insulin, has low affinity (high Km) for glucose, and doesn't get inhibited by G-6P. Hexokinase is in all tissues, not affected by insulin, has high affinity (low Km) for glucose, and is inhibited by G-6P.

    Signup and view all the flashcards

    Pyruvate Metabolism

    Pyruvate can be converted anaerobically to lactate in muscle cells, etc.; anaerobically to ethanol (fermentation); or aerobically to CO2 and H2O via the citric acid cycle.

    Signup and view all the flashcards

    Glycolysis Energy Yield

    Aerobic glycolysis yields 8 ATP, while anaerobic glycolysis yields 2 ATP.

    Signup and view all the flashcards

    Glycolysis Intermediate

    Glycolysis produces crucial intermediates like 3-phosphoglycerate, which is essential for amino acid serine synthesis.

    Signup and view all the flashcards

    Oxygenation of Tissues via Glycolysis

    Through the formation of 2,3-bisphosphoglycerate, glycolysis reduces hemoglobin's affinity for oxygen, aiding oxygen delivery to tissues.

    Signup and view all the flashcards

    Biological Importance of Glycolysis

    Glycolysis provides energy, crucial intermediates for other pathways, and contributes to oxygen delivery to tissues.

    Signup and view all the flashcards

    Study Notes

    Intended Learning Outcomes

    • Students should be able to understand the key aspects of glycolysis by the end of the lecture.

    Glycolysis

    • Glycolysis is the oxidation of glucose to pyruvate, occurring in the presence of oxygen or resulting in lactate production in the absence of oxygen.
    • The process occurs in the cytoplasm of all tissue cells.
    • Glycolysis is crucial for tissues lacking mitochondria, such as mature Red Blood Cells (RBCs).

    Glycolysis: Specific Tissue Functions

    • RBCs: Exclusively rely on glycolysis for energy production.
    • Skeletal Muscle: A primary energy source during high-intensity exercise.
    • Adipose Tissue: Produces glycerol-P for Triglyceride (TG) synthesis and acetyl-CoA for Fatty Acid (FA) synthesis.
    • Liver: Involved in acetyl-CoA production for FA synthesis and glycerol-P for TG synthesis.

    ATP Yield in Glycolysis

    • ATP calculation is based on ATP generated minus ATP utilized.
    • Anaerobic glycolysis produces a net gain of 2 ATP.
    • Aerobic glycolysis yields 8 ATP.

    Glycolysis Pathway

    • (Diagram needed here for accurate notes, but the provided text outlines the steps and enzymes involved.)*
    • Glucose is phosphorylated to glucose-6-phosphate.
    • Fructose-6-phosphate is phosphorylated to fructose-1,6-bisphosphate.
    • The 6-carbon molecule fructose-1,6-bisphosphate is split into two 3-carbon molecules (glyceraldehyde-3-phosphate(G3P) and dihydroxyacetone phosphate(DHAP)).
    • G3P is further metabolized to produce ATP and NADH.
    • After a series of enzymatic reactions, pyruvate is formed.

    Differences between Glucokinase and Hexokinase

    Feature Glucokinase Hexokinase
    Site Liver cells only All tissues
    Substrate Glucose only Hexoses
    Insulin Stimulated No effect
    Affinity Low (high Km) High (low Km)
    G-6-P No effect Inhibited
    Glucose levels Acts over 100 mg% Acts on low glucose levels

    Difference between Aerobic and Anaerobic Glycolysis

    Feature Aerobic Glycolysis Anaerobic Glycolysis
    End Product Pyruvate Lactate
    Energy 8 ATP 2 ATP
    NAD+ Regeneration Through respiratory chain in mitochondria Through lactate formation

    Biological Importance of Glycolysis

    • Energy Production: Anaerobic glycolysis generates 2 ATP, while aerobic glycolysis yields 8 ATP.
    • Oxygenation of Tissues: Formation of 2,3-bisphosphoglycerate decreases hemoglobin's affinity for oxygen.
    • Intermediate Production: 3-phosphoglycerate is an intermediate, forming amino acid serine.
    • Mitochondrial Fuel Source: Aerobic glycolysis provides pyruvate to the Krebs Cycle via the formation of acetyl CoA.

    Fate of Pyruvate

    • Anaerobic glycolysis: Pyruvate is reduced to lactate.
    • Alcoholic fermentation: Pyruvate is converted to ethanol.
    • Aerobic respiration: Pyruvate enters the Citric Acid Cycle (Krebs Cycle).

    Fermentation

    • Anaerobic organisms lack a respiratory chain.
    • They oxidize NADH by reducing pyruvate to lactate or other more reduced compounds.
    • Fermentation includes glycolysis plus the reoxidation of NADH.
    • The process is needed to oxidize NADH in the absence of an electron transport chain.
    • Pyruvate is the product in this process.

    Lactate Dehydrogenase

    • Lactate Dehydrogenase (LDH) catalyzes the reduction of pyruvate to lactate, oxidizing NADH to NAD+.
    • Lactate is a mobile nutrient energy source and potential signaling molecule in mammals.
    • Cells have carrier proteins to facilitate lactate transport.

    Lactate Metabolism

    • Lactate produced in active skeletal muscles can be released into the bloodstream and taken up by other tissues.
    • Lactate can be converted back into pyruvate by LDH.
    • Pyruvate can then enter the Krebs Cycle or be converted to glucose via gluconeogenesis in the liver.

    Regulation of Glycolysis

    • Glycolysis is controlled by 3 irreversible enzymes:
    • Glucokinase/hexokinase
    • Phosphofructokinase-1
    • Pyruvate kinase.
    • Insulin stimulates the last 3 enzymes, boosting glycolysis.
    • Adrenaline and glucagon inhibit pyruvate kinase, limiting the process.
    • G-6-P inhibits hexokinase(not glucokinase) while citrate inhibits phosphofructokinase.
    • High/low levels of ATP,ADP and AMP can regulate the process.

    Sources of Lactate

    • Skeletal muscles, during high-intensity exercise which produces lactate,
    • Astrocytes, which produce and release lactate in the brain. In RBCs, NAD+ regeneration converts pyruvate into lactate.

    Lactate's Function

    • Lactate is an end-product of fermentation.
    • It's a mobile form of energy.
    • Cell membranes contain carriers for lactate transport.
    • Lactate in blood can be used by other cells or converted back to pyruvate.

    Studying That Suits You

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

    Quiz Team

    Related Documents

    Glycolysis Notes PDF

    Description

    This quiz covers key aspects of glycolysis, including its process of converting glucose to pyruvate and its importance in different tissues such as RBCs, skeletal muscle, and liver. Understand how ATP yield varies in aerobic and anaerobic conditions and the role of glycolysis in energy production.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser