Question

Which one of the following is an enzyme?

• A. Glucagon
• B. Insulin
• C. Somatotropin
• D. Trypsin

Hint:

Trypsin is a protein digesting enzyme from the pancreas, while the other three options are hormones.

Answer 1

The Correct Option is D

Step 1: Know the difference between a hormone and an enzyme.
A hormone is a chemical messenger released into the blood by a gland, and it travels to a distant organ to change how that organ works. An enzyme is a protein that speeds up a specific chemical reaction, usually by breaking down or building up a molecule, and it works at the site where the reaction happens rather than travelling through the blood to send a message.

Step 2: Identify trypsin.
Trypsin is a digestive enzyme made by the pancreas and released into the small intestine. Its job is to break the peptide bonds in proteins, cutting large protein molecules into smaller peptides so the body can absorb them. Since its function is to speed up a chemical breakdown reaction, trypsin is an enzyme.

Step 3: Check why the other three are hormones, not enzymes.
Glucagon is a hormone made by the alpha cells of the pancreas. It raises blood sugar by signalling the liver to break down stored glycogen into glucose. It is a messenger, not a reaction speeding protein acting locally.
Insulin is a hormone made by the beta cells of the pancreas. It lowers blood sugar by signalling body cells to take up glucose from the blood. Like glucagon, it works by sending a signal, not by directly speeding up a reaction.
Somatotropin, better known as growth hormone, is released by the pituitary gland and signals tissues throughout the body to grow. It is also a signalling molecule rather than a catalyst.

Step 4: Final answer.
Trypsin is the one option that works as a catalyst for a specific chemical reaction, so it is the enzyme among the four.
\[ \boxed{\text{Trypsin}} \]