Question

Which of the following accurately describes an example of how materials can move across the cell membrane through active transport?

A protein acts as a channel to allow large, hydrophilic molecules to diffuse across the cell membrane.

A protein acts as a pump and moves calcium ions from an area of low concentration to an area of high concentration.

The cell membrane folds to surround a substance and bring the substance inside the cell during exocytosis.

Water moves by osmosis from higher concentration to lower concentration by passing through proteins called aquaporins.