Protein and Enzymes Sequencing Quiz
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Questions and Answers

What is the area on the enzyme where the substrate attaches called?

  • Binding site
  • Inhibitory site
  • Catalytic site (correct)
  • Inactive site
  • What do we call the substance at the beginning of an enzymatic reaction on which an enzyme acts?

  • Coenzyme
  • Substrate (correct)
  • Activator
  • Inhibitor
  • What is the term used for an enzyme without its non-protein moiety?

  • Coenzyme
  • Apoenzyme (correct)
  • Holoenzyme
  • Prosthetic group
  • Which type of cofactor is tightly bound to the apoenzyme by covalent bonds?

    <p>Prosthetic group</p> Signup and view all the answers

    What is the term for a non-protein chemical compound bound to an enzyme and required for catalysis?

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

    What type of cofactor is derived from vitamins and loosely bound to the apoenzyme by non-covalent bonds?

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

    What is the purpose of using 1-fluoro-2-4-dinitrobenzene (DNB) in sequencing polypeptides?

    <p>To label the first amino acid</p> Signup and view all the answers

    In Edman Degradation, what does phenylisothiocyanate label?

    <p>The first amino acid</p> Signup and view all the answers

    What happens if Edman Degradation is repeated several times on a polypeptide?

    <p>It allows for the determination of the entire sequence</p> Signup and view all the answers

    Under acidic conditions, what happens to the bonds in a polypeptide chain when reacting with Sanger Reagent?

    <p>Bonds between certain amino acids break</p> Signup and view all the answers

    What is the consequence of using 1-fluoro-2-4-dinitrobenzene (DNB) on the rest of the polypeptide chain?

    <p>It destroys the rest of the polypeptide chain</p> Signup and view all the answers

    What allows for repeated use of phenylisothiocyanate in Edman Degradation?

    <p>Basic conditions</p> Signup and view all the answers

    Which environmental factor has the most significant impact on enzyme activity?

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

    What is the primary mechanism by which a competitive inhibitor slows down an enzymatic reaction?

    <p>It binds to the enzyme's active site, preventing the substrate from binding</p> Signup and view all the answers

    What is the optimal pH range for most enzymes?

    <p>pH 6 - 8</p> Signup and view all the answers

    How does substrate concentration affect the rate of an enzymatic reaction?

    <p>The rate increases until the enzyme is saturated, then remains constant</p> Signup and view all the answers

    What is the role of cofactors in enzymatic reactions?

    <p>Cofactors are inorganic substances that are necessary for proper enzyme activity</p> Signup and view all the answers

    How do competitive inhibitors affect the $K_m$ (Michaelis constant) of an enzymatic reaction?

    <p>The $K_m$ increases, indicating lower substrate affinity</p> Signup and view all the answers

    What is the main difference between the lock-and-key model and the induced-fit model of enzyme action?

    <p>The lock-and-key model involves a rigid active site, while the induced-fit model has a flexible active site.</p> Signup and view all the answers

    How does an enzyme increase reaction rates according to the text?

    <p>By decreasing the activation energy of the reaction</p> Signup and view all the answers

    What happens within the active site of an enzyme-substrate complex?

    <p>The reaction occurs to convert substrate to product</p> Signup and view all the answers

    What is one limitation of the lock-and-key model of enzyme action?

    <p>It cannot explain the flexibility of enzyme active sites</p> Signup and view all the answers

    How do enzymes achieve varying degrees of specificity for substrates?

    <p>By adjusting their active site and shape to maximize fit</p> Signup and view all the answers

    What is the overall reaction for the conversion of substrate to product in enzyme-catalyzed reactions?

    <p>$E + S \xrightarrow{ES} E + P$</p> Signup and view all the answers

    Which of the following statements about non-competitive inhibitors is correct?

    <p>They bind to a site other than the active site, causing a conformational change that disrupts substrate binding.</p> Signup and view all the answers

    Which of the following is a common naming convention for enzymes?

    <p>Enzyme names describe the substrate and the function, e.g., alcohol dehydrogenase.</p> Signup and view all the answers

    Which of the following is NOT one of the six functional classes of enzymes according to the International Union of Biochemists (I.U.B.)?

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

    What is the biochemical activity of oxidoreductases?

    <p>Catalyze the addition or removal of hydrogen atoms in oxidation/reduction reactions.</p> Signup and view all the answers

    Which of the following statements about competitive inhibitors is correct?

    <p>They bind to the active site of the enzyme, mimicking the substrate.</p> Signup and view all the answers

    Which of the following is an example of a common name used for a digestive enzyme?

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

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