Which of the following units have a shape that is complementary to each other,similar to a lock and key?

Identify $P, Q,$ and $R$ in the following descriptions:
$P -$ The component that undergoes transformation in a chemical reaction.
$Q -$ The component formed as a result of transformation in a chemical reaction.
$R -$ The component that remains unchanged after the completion of a chemical reaction.
What are $P, Q,$ and $R$ respectively?

These enzymes catalyze the breakdown of large molecules into smaller units without the addition of water molecules.

During an enzymatic reaction,the nature of the transition state of the substrate is -

Which one of the following statements about cytochrome $P_{450}$ is wrong?

What is the proteinaceous part of an enzyme called?