Which group of compounds ensures that metabolic reactions take place effectively?

Enzymes

Explanation:

Enzymes are protein in nature, they catalyze metabolic reactions. They are found within the cell at specific temperature, pressure and pH.

Enzymes are specific in nature and they act on substrate.

During metabolic reaction enzymes binds with substrate at active site to form an enzyme - substrate and they increase chemical reaction in the cell by reducing activation energy.

Enzymes are reused because they do not get exhausted in a chemical reaction but rather act as catalyst and can also bind with another substrate to speed up reactions.