Question

Jana is developing a model of the use of food in the human body. She wants the model to explain the roles of dietary proteins, carbohydrates, and fats.

Which statement about one of these nutrients would be most useful for the model to represent?

A.
Only carbohydrates can be broken apart into smaller molecules.
B.
Only proteins contain nitrogen, an essential element for life and for supporting growth.
C.
Only fats contain energy in a form that the body can use.
D.
Only carbohydrates are useful for supporting the growth of the body.

Answer 1

B

Proteins (unlike most dietary carbohydrates and fats) contain nitrogen in their amino acids. That nitrogen is essential for building body tissues and supporting growth (and for making other N‑containing molecules like nucleic acids), so representing that fact is important for Jana’s model.