Question

Which component is required for the activation of some enzymes?

Answer 1

The best answer is letter A. 
The main factors that change the speed of enzymatic reactions are temperature, pH and substrate concentration (quantity). There are enzymes that need other associated molecules to work. These molecules are called enzyme co-factors. They can be organic ions like mineral salts.

Answer 2

The correct answer is option A.

Presence of a co-factor is required for the activation of some enzymes. Co-factors are generally metal ions or small molecules (non-protein).Co-factors helps enzymes bind substrate tightly.  For example, NAD⁺/NADH is a co-factor which is required for the activation of the enzyme dehydrogenase. NAD⁺ is the oxidized form and NADH is the reduced form.