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Glucose and Glycogen Regulation Practice 1 quiz

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  • What is the most sensitive indicator of a cell's energetic status?
    AMP is the most sensitive indicator because its concentration fluctuates greatly compared to ADP and ATP.
  • Which enzyme breaks down glycogen by cleaving alpha-1,4 bonds?
    Glycogen phosphorylase breaks down glycogen by cleaving alpha-1,4 bonds.
  • What is the product released when glycogen phosphorylase acts on glycogen?
    The product is glucose-1-phosphate, which must be converted to glucose-6-phosphate.
  • Which enzyme assists glycogen phosphorylase by removing branch point glucoses?
    The debranching enzyme assists by removing branch point glucoses.
  • What type of bond does the glycogen branching enzyme form?
    It forms alpha-1,6 bonds, which are the branch points in glycogen.
  • How does the glycogen branching enzyme create branches in glycogen?
    It transfers about 6 to 10 glucose subunits to the 6th position of a glucose on another chain.
  • What is the role of glycogenin in glycogen synthesis?
    Glycogenin serves as the primer for glycogen synthesis, with initial sugars attached to its tyrosine residues.
  • How does glucose affect glycogen phosphorylase A?
    Glucose allosterically inhibits glycogen phosphorylase A by exposing its phosphate groups for deactivation.
  • What is the active form of glycogen phosphorylase called?
    The active form is called glycogen phosphorylase A, which is the phosphorylated form with two phosphate groups.
  • How does glucose lead to the deactivation of glycogen phosphorylase?
    Glucose exposes the phosphate groups on glycogen phosphorylase, allowing another enzyme to remove them and deactivate it.
  • Which enzyme is inhibited by ATP in glycolysis regulation?
    Phosphofructokinase-2 (PFK-2) is inhibited by ATP.
  • What does phosphofructokinase-2 produce to activate PFK1?
    It produces fructose-2,6-bisphosphate, which activates PFK1.
  • Why does ATP inhibit phosphofructokinase-2?
    ATP is a downstream product of glycolysis, so it acts as a negative feedback inhibitor of PFK-2.
  • What is the function of PFK1 in glycolysis?
    PFK1 promotes glycolysis by catalyzing a key regulatory step in the pathway.
  • How does glycolysis contribute to ATP production?
    Glycolysis directly produces ATP and also generates intermediates for further ATP production via the citric acid cycle and electron transport chain.