C1.1 Enzymes and metabolism (Molecules): Practice Questions

• a.

  To provide energy for endergonic reactions.

• b.

  To increase the activation energy required for a reaction to occur.

• c.

  To decrease the activation energy of a reaction, thereby increasing its rate.

• d.

  To permanently alter the chemical equilibrium of a reaction.

• a.

  The reaction rate will remain constant, as all active sites are saturated.

• b.

  The reaction rate will continue to increase linearly.

• c.

  The reaction rate will decrease due to substrate inhibition.

• d.

  The enzyme will denature, causing the reaction to stop.

• a.

  Both product X and product Y independently activate the enzyme converting A to B.

• b.

  Both product X and product Y competitively inhibit the enzyme converting A to B.

• c.

  Product X inhibits the enzyme converting B to X, and product Y inhibits the enzyme converting B to Y.

• d.

  A high concentration of product X non-competitively inhibits the enzyme converting B to Y.

• a.

  Its activity would be temporarily reduced at pH 7 but fully restored upon return to pH 2.

• b.

  The enzyme would be permanently denatured, leading to a significant loss of activity even after returning to pH 2.

• c.

  The \(K_m\) for its substrate would decrease at pH 7, indicating increased affinity, but \(V_{max}\) would remain unchanged.

• d.

  It would begin to function as an allosteric enzyme at pH 7, gaining new regulatory properties.

• a.

  The sigmoidal curve becomes more hyperbolic, and the apparent affinity for the substrate increases.

• b.

  The \(V_{max}\) value decreases, and the curve shifts to the left.

• c.

  The \(K_m\) value increases, making the sigmoidal curve steeper.

• d.

  The enzyme becomes saturated at lower substrate concentrations, but its cooperativity increases.

Write your answer out first, then check it against the worked solution.

Write your answer out first, then check it against the worked solution.