MasteringBiology Chapter 5

Fluidity of an animal cell plasma membrane is enhanced by __________.

Cholesterol molecules

Frequently, transplante organs are rejected by the recipent's body. How is this reaction related to the plasma membrane?

Each person has a unique set of carbohydrate chains attached to his or her plasma membranes.

When considering the formation of membranes, they __________.

Form spontaneously in aqueous environments.

The lipids in a cell membrane are arranged how?

So that the nonpolar parts of two lipids point towards each other.

The eukaryotic cell has multiple membrane-enclosed compartments. This evolutionary innovation provides what advantage to the cell?

The different membrane-enclosed spaces allow different parts of the cell to perform specific functions.

In an oil-based, non-polar environment, phospholipids would arrange themselves so that they

Would stay together, but in reverse orientation, with their tails projecting outward.

The movement of atoms, ions, or molecules from a region of higher concentration to regions of lower concentration is called

Diffusion

The plasma membrane is selectively permeable. Which of the following can pass freely through the membrane with no assistance?

Oxygen and carbon dioxide.

Overall, membranes seem to have a great deal in common, but on closer inspection it is revealed that membranes of different cells have unique properties. What is the primary component of membranes that gives membranes cell-specific properties?

Proteins

What controls the direction of molecules, such as oxygen, involved in passive transport?

The direction of the oxygen concentrated gradient.