Celery stalks are immersed in fresh water for several hours and become stiff and hard. Similar stalks left in salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are

The presence of cholesterol in the plasma membranes of some animals

The selective permeability of biological membranes is dependent on which of the following?

All of the following molecules are part of the cell membrane except

According to the fluid mosaic model of cell membranes, which of the following is a true statement about membrane phospholipids?

In a hypertonic solution, an animal cell will

All of the following processes take materials into the cell except

The interior of the phospholipid bilayer is

The following pictures are examples of which of the following?

What are the membrane structures that function in active transport?

In a hypotonic solution, an animal cell will

Endocytosis moves materials _______ a cell via _________

All of the following membrane activities require energy from ATP hydrolysis except