An enzyme is always a protein an organic molecule that catal

An enzyme is always a protein. an organic molecule that catalyzes a cellular reaction, used up in a reaction. All of the answer choices are correct. not necessary to sustain life in a cell.

Solution

Ans . B

all enzymes are organic molecules mostly proteins , but few are catalytic RNA molecules that catalyse the cellular reactions in our body by lowering the activation energy barrier.

They are catalysts of biological living systems.