Most enzymes catalyze a chemical reaction in both directions.Which is the best explanation of this statement?
A) Chemical reaction in both directions means the direction and rate of the reaction is being governed by gravity; for example, food in the lower digestive tract is moved by peristalsis, whereas food in the upper part of the digestive tract is moved by segmentation.
B) Chemical reaction in both directions means that enzymes are both intracellular and extracellular, depending on whether they act within cells or outside them in the surrounding medium.
C) Chemical reaction in both directions means the direction and rate of the reaction is being governed by the rate law or law of mass action; for example, slowing of digestion when absorption is interfered with and the products of digestion accumulate.
D) Both B and C are accurate explanations.

Question

Quizplus · Accepted Answer

Enzymes catalyze a chemical reaction in both directions, meaning they can both help speed up the forward reaction and the reverse reaction. The direction and rate of the reaction are determined by the rate law or law of mass action, which takes into account the concentration of reactants and products. This is why digestion may slow down when absorption is interfered with and the products of digestion accumulate. Choice A is incorrect because gravity does not govern the direction or rate of chemical reactions. Choice B is incorrect because whether an enzyme is intracellular or extracellular does not determine whether it can catalyze a reaction in both directions. Choice D is incorrect because only choice C accurately explains the statement.

Most Enzymes Catalyze a Chemical Reaction in Both Directions