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

Identify the odd one out based on function.

An average living cell contains about:

Which statement is not correct for an enzyme?

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?

The transition state structure of the substrate formed during an enzymatic reaction is: