Biochemistry: Glycolysis Overview
43 Questions
0 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 product of glycolysis from glucose metabolism?

  • Glycogen
  • 4 ATP
  • NADH
  • 2 pyruvate (correct)

    • Which carbohydrate serves as a major nutrient derived from ingested plant cells for glycolysis?

  • Sucrose
  • Fructose
  • Starch (correct)
  • Lactose

    • What is produced when pyruvate is formed during glycolysis?

  • 2 NADH (correct)
  • 6 CO2
  • 2 FADH2
  • 4 ATP

    • Which compound represents the major form of carbohydrate storage in animals?

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

    What happens to NADH when lactate is formed as an end product in glycolysis?

    <p>NADH is converted back to NAD+</p> Signup and view all the answers

    What type of glycolysis occurs when there is an adequate supply of oxygen?

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

    Which disaccharide is a major carbohydrate component of milk, contributing to glycolysis?

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

    Which is NOT considered a carbon source for glycolysis?

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

    Which of the following correctly describes the relationship between glucose and pyruvate during glycolysis?

    <p>Glucose is broken down into pyruvate.</p> Signup and view all the answers

    What is the primary reason for lactic acidosis in the blood?

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

    What characterizes pyruvate kinase deficiency?

    <p>It causes chronic hemolytic anemia restricted to erythrocytes.</p> Signup and view all the answers

    Which of the following statements about hormonal regulation of glycolysis is true?

    <p>Hormonal influences may lead to a 10-20 fold increase in enzyme activity over time.</p> Signup and view all the answers

    What is a significant consequence of the dependence of RBCs on glycolysis?

    <p>RBCs are capable of anaerobic glycolysis exclusively.</p> Signup and view all the answers

    Which of the following is NOT a possible cause of lactic acidosis?

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

    How does the blood lactate level indicate lactic acidosis?

    <p>Lactic acidosis occurs when blood lactate is 5 mM or more.</p> Signup and view all the answers

    What is the initial product formed from 1,3-Biphosphoglycerate in glycolysis?

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

    Which enzyme catalyzes the conversion of 1,3-BPG to 3-PG?

    <p>Phosphoglycerate kinase</p> Signup and view all the answers

    What factor determines the threshold for insulin secretion in β cells of the pancreas?

    <p>High Km for glucose</p> Signup and view all the answers

    Which of the following statements is true regarding GLUT-2?

    <p>It allows rapid equilibration of blood glucose across the hepatocyte membrane</p> Signup and view all the answers

    Which metabolic condition does insulin secretion mitigate during the absorptive period?

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

    What is the effect of a carbohydrate-rich diet on 1,3-BPG levels?

    <p>It increases 1,3-BPG levels</p> Signup and view all the answers

    Which reaction is catalyzed by enolase in glycolysis?

    <p>Dehydration of 2-Phosphoglycerate</p> Signup and view all the answers

    How does the liver effectively manage blood glucose levels?

    <p>By rapidly removing glucose from portal blood</p> Signup and view all the answers

    Which molecule acts as a regulator of glycolysis by influencing insulin secretion?

    <p>Fructose-6-phosphate</p> Signup and view all the answers

    Pyruvate formation is characterized by which of the following?

    <p>It is an irreversible reaction</p> Signup and view all the answers

    What role does oxygen play in the process of glucose phosphorylation?

    <p>It reoxidizes NADH formed during glyceraldehyde 3-phosphate oxidation.</p> Signup and view all the answers

    What is a consequence of phosphorylating glucose?

    <p>It effectively traps glucose as glucose 6-phosphate.</p> Signup and view all the answers

    How many ATP molecules are produced per mole of glucose during glycolysis?

    <p>6 moles ATP</p> Signup and view all the answers

    What is the primary function of hexokinase I in glycolysis?

    <p>It phosphorylates glucose in most tissues.</p> Signup and view all the answers

    What is the main function of pyruvate carboxylase in the isomerization of DHAP?

    <p>It catalyzes the conversion of DHAP to glyceraldehyde 3-phosphate.</p> Signup and view all the answers

    What happens to glucose when it is phosphorylated?

    <p>It is effectively trapped in the cell.</p> Signup and view all the answers

    What must occur for the oxidative decarboxylation of pyruvate to proceed?

    <p>NAD+ must be present for reoxidation.</p> Signup and view all the answers

    Which of the following correctly describes the reduction of pyruvate to ethanol?

    <p>It requires both pyruvate decarboxylase and alcohol dehydrogenase.</p> Signup and view all the answers

    What occurs during the conversion of hexose to triose phosphate in glycolysis?

    <p>A 6-carbon sugar splits into two 3-carbon sugars.</p> Signup and view all the answers

    What is the role of NAD+ in the oxidation of glyceraldehyde 3-phosphate?

    <p>It functions as an electron carrier.</p> Signup and view all the answers

    What is a significant feature of phosphorylated sugar molecules?

    <p>They do not diffuse easily out of cells.</p> Signup and view all the answers

    What is the primary product of anaerobic glycolysis?

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

    What is the energy yield of anaerobic glycolysis in comparison to aerobic glycolysis?

    <p>Anaerobic glycolysis can be up to 100 times faster than aerobic glycolysis.</p> Signup and view all the answers

    Which of the following statements is true regarding ATP usage during glycolysis?

    <p>Two moles of ATP are consumed per mole of hexose split.</p> Signup and view all the answers

    Which enzyme catalyzes the conversion of pyruvate to alanine?

    <p>Alanine aminotransferase</p> Signup and view all the answers

    In the context of glycolysis, what does the term 'energy yield' refer to?

    <p>The net ATP produced per glucose molecule during glycolysis.</p> Signup and view all the answers

    What is the significance of the enediolate intermediate during the isomerization of DHAP?

    <p>It allows for the reversible conversion between DHAP and glyceraldehyde 3-phosphate.</p> Signup and view all the answers

    Which process directly links glycolysis to gluconeogenesis?

    <p>Isomerization of DHAP and glyceraldehyde 3-phosphate.</p> Signup and view all the answers

    Study Notes

    Overview of Glycolysis

    • Glycolysis is the initial step in glucose metabolism, converting glucose to 2 pyruvate and generating a net production of ATP.
    • Oxygen is essential in aerobic glycolysis for the reoxidation of NADH.

    Carbon and Energy Sources for Glycolysis

    • Starch: Major nutrient from plant cells.
    • Lactose: Disaccharide made of glucose and galactose; main carbohydrate in milk.
    • Fructose: Ketose isomer of glucose; significant when sucrose intake is high.
    • Glucose: Main form of carbohydrate presented to body cells, derived from starch digestion.
    • Glycogen: Animal carbohydrate storage, a highly branched glucose polymer.

    Reactions of Glycolysis

    • 2 molecules of NADH produced during pyruvate formation, which is the end product in aerobic conditions.
    • Aerobic Glycolysis Process:
      • Conversion of glucose to glucose-6-phosphate via hexokinase I is irreversible.
      • Produces 6 moles of ATP per mole of glucose.
      • High Km for hexokinase allows liver to manage blood glucose.

    Stages of Glycolysis

    • Hexose to Triose Phosphate Conversion: Splits a 6-carbon sugar into two 3-carbon sugars, requiring 2 ATP.
    • ATP Formation from 1,3-Bisphosphoglycerate (1,3-BPG): Generates ATP via phosphoglycerate kinase.
    • DHAP Isomerization: Equilibrates dihydroxyacetone phosphate and glyceraldehyde 3-phosphate; yields 2 molecules of glyceraldehyde 3-phosphate.
    • Glyceraldehyde 3-Phosphate Oxidation: Converts to 1,3-BPG, the first redox reaction, requiring NAD+.
    • Reduction of Pyruvate to Lactate: Final product of anaerobic glycolysis.
    • Reduction of Pyruvate to Ethanol: Occurs in yeast and some microorganisms.
    • Pyruvate to Alanine: Links carbohydrate and amino acid metabolism.

    Energy Yield of Glycolysis

    • Anaerobic Glycolysis: Fast glucose catabolism yielding 2 ATP and lactate.
    • Aerobic Glycolysis: Efficient metabolism, producing 2 pyruvate, 2 NADH, and additional ATP.
    • Common enzyme deficiencies: Pyruvate Kinase Deficiency leads to hemolytic anemia; others include glucose phosphate isomerase and triose phosphate isomerase deficiencies.

    Lactic Acidosis

    • Normal blood lactate level is 1.2 mM; levels above 5 mM indicate lactic acidosis.
    • Caused by increased lactate formation or decreased utilization, leading to lower pH and bicarbonate.

    Hormonal Regulation of Glycolysis

    • Short-term regulation involves allosteric mechanisms and enzyme phosphorylation, affecting activity within minutes to hours.
    • Hormonal influences provide slower but more substantial regulatory effects, enhancing enzyme activity 10-20 fold over hours to days.

    Glycolysis and RBC Metabolism

    • Mature red blood cells lack mitochondria, relying entirely on glycolysis for ATP production.

    Studying That Suits You

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

    Quiz Team

    Related Documents

    Biochemistry Glycolysis PDF

    Description

    This quiz covers the glycolysis pathway, an essential metabolic process where glucose is converted into pyruvate, producing net ATP. Learn about the key steps, sources of carbon, and energy required for glycolysis. Test your understanding of this fundamental biochemical process.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser