Question

Given below is the set of four terms in which one is odd. Identify the odd one in each set and name the category to which remaining three belong.

• A. Haemoglobin
• B. Glucagon
• C. Iodopsin
• D. Rhodopsin

Answer 1

The correct option is B

Glucagon

The correct option is B.

Explanation of correct option:

1. Glucagon is a hormone that causes liver glycogen to convert back to glucose and enter the bloodstream, where it can be used for energy by the body.
2. Glycogen is glucose that has been stored (sugar). It is mostly stored in the liver and muscles.

Explanation of the incorrect option:

Option A:

1. The iron-containing pigment hemoglobin allows red blood cells to transport large amounts of oxygen to tissues.

Option C:

1. Iodopsin is a photosensitive violet pigment in the retinal cones that is comparable to rhodopsin but more labile and is vital in daylight vision.
2. It is generated from vitamin A.

Option D:

1. Rhodopsin is a pigment-containing sensory protein that turns light into an electrical signal.
2. It is also known as visual purple.

Final answer: The odd term is glucagon which is a hormone, whereas the other three terms, hemoglobin, iodopsin, and rhodopsin, are RBC, cone, and rod pigments, respectively.