Question

A scientist is comparing the outer layer of an onion cell to the outer layer of a human skin cell. What is unique about the outer layer of the onion cell compared to the skin cell?
It contains proteins.
It contains cellulose.
It contains carbohydrates.
It is selectively permeable.

Answer 1

It contains cellulose.

Explanation: Onion cells (plant cells) have a rigid cell wall made largely of cellulose (a carbohydrate polymer). Human skin cells (animal cells) lack a cellulose cell wall; they have only a plasma membrane (with proteins and carbohydrates) and, in skin, layers of keratin, but not a cellulose cell wall.