Question

Hormones differ from enzymes in the respect that they
(a) Are found only in animals
(b) Are found only in plants
(c) Are used completely in metabolism
(d) Are not used up in metabolism

Answer 1

Hint: Enzymes are biological catalysts that catalyze biological reactions. While doing so, some changes occur in their structure but after the completion of the reaction, they get their original structure and are ready to catalyze another reaction.

Complete answer:
Hormones are not biological catalysts like enzymes. When they participate in chemical reactions, a change in their structure and composition occurs and thus they cannot be reutilized in a reaction as before but in the case of enzymes, the thing is different. During the reaction the structure of enzyme changes but after the completion of the reaction, the enzyme is released in the same form as it was before the reaction. Hence, hormones are used up in the metabolic reactions but enzymes are not.
Hormones and enzymes differ in many other aspects also. In most of the cases, the enzyme performs its action at the place of its origin but the activity of hormone is performed by some distant site from the point of origin and it travels to that site via the bloodstream. Regarding the chemical nature, enzymes are generally proteins with very few exceptions but hormones can be polypeptides steroids, terpenoids, amines, or phenolics.
So, the correct answer is ‘Are used completely in metabolism’.

Note: Hormones and enzymes are found in both plants and animals but chemically they are somewhat different in both of these living things. Just like the animals, the growth, fruit formation, fruit ripening, etc. in plants occur by the action of some hormones that are called plant growth regulators.