At high substrate concentrations, increasing substrate further has no effect on rate because

  1. all active sites are occupied
  2. the enzyme is denatured
  3. pH has changed
  4. the substrate is inhibited
Answer

A) all active sites are occupied

The enzyme is saturated. AS & A Level Biology · Topic 3 Enzymes · 3.2 Factors that affect enzyme action

Biology MCQ · More A Level Biology: Enzymes MCQs · Practise