Glucogenic Amino Acids Pathway: Alanine to Pyruvate
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Questions and Answers

Which process involves converting other carbohydrates to glucose, but is not considered as gluconeogenesis?

  • Glycogenolysis
  • Gluconeogenesis
  • Glycolysis
  • Glycogenesis (correct)

    • What is the primary substrate used in gluconeogenesis?

  • Proteins
  • Nucleic acids
  • Carbohydrates (correct)
  • Fats

    • Which process involves breaking down glycogen to release glucose into the bloodstream?

  • Glycogenolysis (correct)
  • Ketogenesis
  • Gluconeogenesis
  • Glycolysis

    • In the context provided, what process specifically refers to the conversion of non-carbohydrate sources to glucose?

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

    Which metabolic pathway involves the breakdown of glucose into pyruvate?

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

    What is the precursor for entering the glucogenic pathway?

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

    What transformation does alanine undergo to enter the glucogenic pathway?

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

    Which keto acid does alanine become after transamination?

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

    What is the easiest amino acid to enter into the glucogenic pathway?

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

    Which metabolic pathway does alanine enter after transamination?

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

    What is the first step in the process described?

    <p>High concentration</p> Signup and view all the answers

    What does the compound attach to in the process?

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

    Which step results in the activation of cAMP synthesis?

    <p>Attaching to GPCR</p> Signup and view all the answers

    What is the final step in the described process?

    <p>Protein kinase A attachment</p> Signup and view all the answers

    Which component is responsible for activating protein kinase A in the process?

    <p>cAMP synthesis</p> Signup and view all the answers

    What is the main difference between the enzymes in glycolysis and gluconeogenesis?

    <p>Enzymes in glycolysis have a positive ΔG in phosphorylation, while enzymes in gluconeogenesis have a negative ΔG.</p> Signup and view all the answers

    Where does the process described occur, according to the text?

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

    What molecule provides both energy and a phosphate group for the phosphorylation of glucose in glycolysis?

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

    Why is it necessary to couple the phosphorylation in glycolysis with ATP hydrolysis?

    <p>To generate a negative net ΔG</p> Signup and view all the answers

    Which of the following organs does NOT play a role in the process described?

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

    What are the products when 1,3 bisphosphoglycerate is converted to glyceraldehyde 3-P during gluconeogenesis?

    <p>Inorganic phosphate, 2 NAD+</p> Signup and view all the answers

    What happens when 3-phosphoglycerate is converted to 1,3 bis-phosphoglycerate in gluconeogenesis?

    <p>2 ATP are hydrolyzed to 2 ADP</p> Signup and view all the answers

    Which molecules are oxidized into NAD+ during gluconeogenesis?

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

    What role does inorganic phosphate play in the conversion of 1,3 bisphosphoglycerate to glyceraldehyde 3-P?

    <p>It is released</p> Signup and view all the answers

    How many ATP molecules are hydrolyzed to ADP during the conversion of 3-phosphoglycerate to 1,3 bis-phosphoglycerate?

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

    Where does gluconeogenesis occur?

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

    Which component is NOT involved in gluconeogenesis?

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

    When does gluconeogenesis primarily take place?

    <p>During fasting or starvation</p> Signup and view all the answers

    Which of the following is NOT a site where gluconeogenesis occurs?

    <p>Skeletal muscle</p> Signup and view all the answers

    Besides the liver and kidneys, where else can gluconeogenesis occur?

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

    What happens to glycerol once it is released from the adipocytes?

    <p>It travels through the bloodstream on albumin</p> Signup and view all the answers

    How are fatty acids transported in the bloodstream?

    <p>Bound to lipoproteins</p> Signup and view all the answers

    What do different cell types primarily use fatty acids for?

    <p>Energy production</p> Signup and view all the answers

    Which protein serves as a carrier for glycerol in the bloodstream?

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

    How is glycerol related to the breakdown of fatty acids?

    <p>Glycerol is a byproduct of fatty acid breakdown</p> Signup and view all the answers

    Which process involves the synthesis of glucose from non-carbohydrate sources?

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

    What is the primary role of gluconeogenesis in metabolism?

    <p>Converting pyruvate into glucose</p> Signup and view all the answers

    What is the fate of alanine after undergoing transamination?

    <p>Converted into glyceraldehyde 3-phosphate for gluconeogenesis</p> Signup and view all the answers

    Which organ primarily regulates the process of gluconeogenesis in the body?

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

    What is the key purpose of gluconeogenesis in terms of maintaining blood glucose levels?

    <p>To stabilize blood glucose levels during fasting or starvation</p> Signup and view all the answers

    What is the function of Glucose 6-phosphatase in relation to Hexokinase/Glucokinase?

    <p>Catalyzes the breakdown of glucose 6-phosphate</p> Signup and view all the answers

    Where does Glucose 6-phosphatase function in the cell?

    <p>Endoplasmic reticulum</p> Signup and view all the answers

    Which transporter is responsible for transporting glucose from the endoplasmic reticulum to the cytosol in hepatocytes/kidney cells?

    <p>Glute 7 transporter</p> Signup and view all the answers

    After exiting the cell, how does glucose reach the bloodstream?

    <p>Through other types of glucose transporters</p> Signup and view all the answers

    What is the role of Hexokinase/Glucokinase in this process?

    <p>Converts glucose to glucose 6-phosphate in the cytosol</p> Signup and view all the answers

    Why is acetyl CoA specifically mentioned as the activator for pyruvate carboxylase?

    <p>Acetyl CoA is produced in large amounts during fatty acid degradation in fasting state</p> Signup and view all the answers

    What happens to the excess acetyl CoA that cannot be utilized by the Krebs cycle in fasting conditions?

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

    In the context provided, what role does pyruvate carboxylase play in gluconeogenesis?

    <p>It catalyzes the conversion of pyruvate to oxaloacetate</p> Signup and view all the answers

    What metabolic state of the cell triggers the activation of pyruvate carboxylase by acetyl CoA?

    <p>Fasting state</p> Signup and view all the answers

    Why does the cell require the activation of pyruvate carboxylase during fasting?

    <p>To generate glucose from non-carbohydrate sources like fatty acids</p> Signup and view all the answers

    Why is ATP not used in the dephosphorylation of Glucose 6-phosphate?

    <p>The phosphatase enzyme has a negative ΔG.</p> Signup and view all the answers

    What drives the dephosphorylation of Glucose 6-phosphate by the phosphatase enzyme?

    <p>Negative ΔG</p> Signup and view all the answers

    In the context of the text, what is the significance of the negative ΔG in the dephosphorylation reaction?

    <p>It facilitates the conversion of Glucose 6-phosphate without ATP.</p> Signup and view all the answers

    Why does dephosphorylation of Glucose 6-phosphate not utilize ATP despite being an energy-requiring process?

    <p>Presence of a negative ΔG</p> Signup and view all the answers

    What metabolic condition would likely alter the need for ATP in the dephosphorylation of Glucose 6-phosphate?

    <p>Starvation state</p> Signup and view all the answers

    What is the enzyme responsible for converting Phosphoenolpyruvate to pyruvate in the final step of glycolysis?

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

    In gluconeogenesis, which enzyme catalyzes the conversion of pyruvate to Phosphoenolpyruvate, the reverse reaction of the last step in glycolysis?

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

    Which molecule serves as the precursor for the synthesis of Phosphoenolpyruvate from pyruvate in gluconeogenesis?

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

    Which of the following enzymes is NOT directly involved in the conversion of Phosphoenolpyruvate to pyruvate in glycolysis or its reverse reaction in gluconeogenesis?

    <p>Fructose-1,6-bisphosphatase</p> Signup and view all the answers

    Which of the following statements regarding Pyruvate kinase is INCORRECT in the context of glycolysis and gluconeogenesis?

    <p>Pyruvate kinase is activated by fructose-6-phosphate in gluconeogenesis.</p> Signup and view all the answers

    What is the initial reaction that takes place in mitochondria involving pyruvate?

    <p>Conversion of pyruvate to oxaloacetate by pyruvate carboxylase</p> Signup and view all the answers

    Why is pyruvate carboxylase activation essential during fasting?

    <p>To convert excess acetyl CoA into pyruvate for energy production</p> Signup and view all the answers

    What is the role of oxaloacetate in the context of pyruvate metabolism?

    <p>It reacts with acetyl-CoA to form citrate in the TCA cycle</p> Signup and view all the answers

    Which enzyme is responsible for catalyzing the conversion of pyruvate to oxaloacetate in the mitochondria?

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

    Which substance is produced as a result of the reaction catalyzed by pyruvate carboxylase?

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

    What is the fate of inorganic phosphate in the conversion of 1,3 bisphosphoglycerate to glyceraldehyde 3-P during gluconeogenesis?

    <p>It is consumed by the reaction</p> Signup and view all the answers

    What is the ultimate outcome of the ATP molecules hydrolyzed to ADP during the conversion of 3-phosphoglycerate to 1,3 bisphosphoglycerate in gluconeogenesis?

    <p>They are used for cellular respiration</p> Signup and view all the answers

    What is the function of 1,3 bisphosphoglycerate in the context of gluconeogenesis?

    <p>Serves as a carrier of high-energy phosphate bonds</p> Signup and view all the answers

    How does NADH contribute to the conversion of 1,3 bisphosphoglycerate to glyceraldehyde 3-P?

    <p>It provides electrons to reduce NAD+</p> Signup and view all the answers

    What is the primary role of NAD+ in the context of gluconeogenesis?

    <p>To carry electrons from NADH</p> Signup and view all the answers

    What is the primary function of Glucose 6-phosphatase in gluconeogenesis?

    <p>Converting glucose 6-phosphate back to glucose</p> Signup and view all the answers

    Which type of transporters are responsible for facilitating the exit of glucose from hepatocytes/kidney cells in gluconeogenesis?

    <p>Fructose transporters</p> Signup and view all the answers

    What is the enzyme responsible for transporting glucose from the endoplasmic reticulum to the cytosol in hepatocytes/kidney cells during gluconeogenesis?

    <p>Glute 7</p> Signup and view all the answers

    What is the main difference between Glucose 6-phosphatase and Hexokinase/Glucokinase in terms of their roles in glucose metabolism?

    <p>Glucose 6-phosphatase converts glucose back to glucose 6-phosphate while Hexokinase/Glucokinase phosphorylate glucose</p> Signup and view all the answers

    In the context of gluconeogenesis, what is the primary role of Glute 7 existing on the ER membrane?

    <p>Facilitating the entry of glucose into the cell</p> Signup and view all the answers

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