Factors Affecting Enzymes Flashcards
All 6 cards in this deck
What happens to the rate of an enzyme-controlled reaction as temperature increases up to the optimum?
The rate increases: molecules have more kinetic energy, so there are more collisions with the active site and more enzyme-substrate complexes form.
What is meant by the optimum pH of an enzyme?
The pH at which the enzyme has its fastest rate of reaction.
e.g. pepsin pH 2, trypsin pH 8What happens to the rate of an enzyme-controlled reaction as substrate concentration is increased?
The rate increases (more collisions with active sites, more enzyme-substrate complexes), then plateaus when all active sites are occupied and the enzyme becomes the limiting factor.
True or false? Boiling an enzyme kills it.
False. Enzymes are not alive — at high temperature the enzyme is denatured and the active site changes shape.
True or false? Cooling an enzyme to 0°C denatures it.
False. Low temperature slows enzyme activity (fewer collisions with the active site) but does not change the shape of the active site, so activity returns when it is warmed.
Why does the rate of an enzyme-controlled reaction fall above the optimum temperature?
The high temperature breaks bonds that hold the enzyme in shape. The active site changes shape and the substrate can no longer bind, so the enzyme is denatured.