Enzyme Function and Mechanisms Quiz
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Questions and Answers

What is the substrate of proteolytic enzymes?

  • Proteins (correct)
  • Vitamins
  • Carbohydrates
  • Lipids

    • What principle does substrate binding to the active site of an enzyme follow?

  • Absolute substratum
  • Thermal stability
  • Complementarity (correct)
  • Electrophoretic properties

    • Which type of enzyme catalyzes the intramolecular transfer of atoms or groups of atoms?

  • Transferases
  • Ligases
  • Hydrolases
  • Isomerases (correct)

    • What is the term for converting an inactive form of pepsin into its active form with a decrease in molecular weight?

    <p>Partial proteolysis</p> Signup and view all the answers

    What is an enzyme called that contains a coenzyme and exhibits enzymatic activity?

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

    What reaction is catalyzed by kinases?

    <p>Transfer of the phosphate group</p> Signup and view all the answers

    What characteristic describes the nature of a competitive inhibitor for an enzyme?

    <p>Analog of the substrate</p> Signup and view all the answers

    In enzyme diagnostics, the enzyme level determined in a patient with liver lesions is typically which enzyme?

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

    What is the substrate for the reaction of substrate phosphorylation?

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

    What occurs during the second stage of glycolysis?

    <p>Formation of glyceraldehyde-3-phosphate</p> Signup and view all the answers

    How is ATP synthesis carried out in the formation of 3-phosphoglycerate from 1,3-bisphosphoglycerate?

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

    In anaerobic glycolysis, how is ATP primarily formed?

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

    What type of glucose oxidation do brain cells primarily use?

    <p>Anaerobic glucose oxidation</p> Signup and view all the answers

    What is the amount of ATP formed during anaerobic glycolysis per 1 mole of glucose?

    <p>3 mole</p> Signup and view all the answers

    What determines the regulation of the rate of glycolysis?

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

    During aerobic glycolysis, ATP formation primarily occurs through which process?

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

    What compound regulates the activity of glycolysis?

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

    Which of the following inhibits phosphofructokinase activity?

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

    What is the inhibitor of hexokinase in many tissues?

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

    How does glucose oxidation occur in the first minutes of muscle contraction?

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

    What process leads to ATP synthesis during prolonged physical activity?

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

    What is the substrate for substrate phosphorylation?

    <p>1,3-bisphosphoglycerate</p> Signup and view all the answers

    What is the main function of the pentose phosphate pathway in red blood cells?

    <p>Formation of NADPH2</p> Signup and view all the answers

    In the pentose phosphate pathway, which enzyme is responsible for forming NADPH2?

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

    Which statement accurately describes enzyme inhibitors?

    <p>They reduce the rate of enzymatic reactions.</p> Signup and view all the answers

    Which vitamin acts as a coenzyme capable of accepting and donating electrons and protons along the pyrimidine ring?

    <p>Vitamin PP</p> Signup and view all the answers

    What is the primary role of vitamins as cofactors in the body?

    <p>To bind to the active site of the enzyme.</p> Signup and view all the answers

    What describes catabolism?

    <p>Decomposition of substances with energy release.</p> Signup and view all the answers

    Which metabolic pathway does thiamine participate in?

    <p>Oxidative decarboxylation of keto acids.</p> Signup and view all the answers

    What is anabolism defined as?

    <p>Synthesis of complex molecules from simpler ones.</p> Signup and view all the answers

    Which product is formed during the catabolism of monosaccharides?

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

    Which of the following describes a common pathway in catabolism?

    <p>The Krebs cycle and oxidative decarboxylation of pyruvate.</p> Signup and view all the answers

    What is the product formed in the non-oxidative stage of the pentose phosphate pathway of glucose conversion?

    <p>ribose-5-phosphate</p> Signup and view all the answers

    Which substances are formed from pentoses in the pentose phosphate cycle?

    <p>purine and pyrimidine nucleotides</p> Signup and view all the answers

    Which product of the pentose phosphate pathway is required for the synthesis of nucleic acids?

    <p>ribose-5-phosphate</p> Signup and view all the answers

    What products of the pentose phosphate cycle are necessary for the synthesis of glucose?

    <p>glyceraldehyde-3-phosphate, fructose-6-phosphate</p> Signup and view all the answers

    What is the reduction of NADP a result of?

    <p>oxidative stage of the pentose phosphate cycle</p> Signup and view all the answers

    Which of the following is the regulatory enzyme of the pentose phosphate pathway?

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

    What is the primary substrate for the pentose phosphate cycle?

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

    Which substrates are primarily involved in gluconeogenesis?

    <p>lactate, amino acids, glycerol, fatty acids, glycerol-3 phosphate</p> Signup and view all the answers

    Which enzyme catalyzes the formation of alpha-1,6-glucosidic bonds?

    <p>amylo-1,4 → 1,6-glucosyltransferase</p> Signup and view all the answers

    Which enzyme is responsible for the formation of UDP-glucose in glycogen synthesis?

    <p>UDP-glucopyrophosphorylase</p> Signup and view all the answers

    Which of the following enzymes is NOT involved in glycogen synthesis?

    <p>glucose-6-phosphatase</p> Signup and view all the answers

    What enzyme catalyzes the cleavage of fructose-1,6-bisphosphate into two phosphotrioses?

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

    In the liver, which process primarily utilizes alanine?

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

    What is synthesized in enterocytes?

    <p>immature chylomicrons</p> Signup and view all the answers

    Which hormone activates triacylglycerol lipase?

    <p>both glucagon and epinephrine</p> Signup and view all the answers

    The substrate for hormone-sensitive TAG-lipase is primarily:

    <p>fats deposited in adipocytes</p> Signup and view all the answers

    Study Notes

    Proteolytic Enzymes

    • Substrates: proteins
    • Key principle of substrate binding: complementarity

    Enzyme Activity Principles

    • Thermal stability is a principle
    • Electrophoretic properties are a principle

    Intramolecular Transfer Enzymes

    • Enzymes that catalyze intramolecular atom/group transfer: isomerases
    • Ligases
    • Transferases
    • Hydrolases
    • Oxidoreductases

    Pepsin Activation

    • Pepsin activation process: partial proteolysis
    • Accompanied by a decrease in molecular weight

    Holoenzymes

    • Enzymes containing a coenzyme and having enzymatic activity: holoenzymes

    Kinase Reactions

    • Kinases transfer phosphate groups from a donor to an acceptor
    • Can involve hydrogen cleavage and transfer
    • Can utilize C-C bond cleavage
    • Can utilize water participation for intramolecular bond cleavage

    Competitive Inhibitors

    • Competitive inhibitors are structural analogs of substrates

    Enzyme Diagnostic Markers

    • Liver enzyme diagnostics use ALT, AST, and CK levels

    Enzyme Properties

    • Enzymes are specific
    • Are typically insensitive to pH
    • Frequently thermally stable

    Allosteric Center

    • Allosteric center of an enzyme binds low-molecular substances
    • Differ in structure from substrates

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    Description

    Test your knowledge on enzymes, their substrates, and catalytic mechanisms with this quiz. It covers topics like proteolytic enzymes, enzyme inhibition, and glycolysis. Perfect for students studying biochemistry or related fields.

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