An enzyme is best described as

  1. a hormone carried in the blood
  2. a carbohydrate that speeds up reactions
  3. a lipid that is used up in reactions
  4. a protein that acts as a biological catalyst
Answer

D) a protein that acts as a biological catalyst

Enzymes are proteins and biological catalysts. O Level Biology · Topic 5 Enzymes · 5.1 Enzyme action

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