Cell Membrane and Transport Quiz

Which plasma membrane component can be either found on its surface or embedded in the membrane structure?

• protein

• cholesterol

• carbohydrate

• phospholipid

Which characteristic of a phospholipid contributes to the fluidity of the membrane?

• its head

• cholesterol

• a saturated fatty acid tail

• double bonds in the fatty acid tail

What is the primary function of carbohydrates attached to the exterior of cell membranes?

• identification of the cell

• flexibility of the membrane

• strengthening the membrane

• channels through membrane

A scientist compares the plasma membrane composition of an animal from the Mediterranean coast with one from the Mojave Desert. Which hypothesis is most likely to be correct?

• The cells from the Mediterranean coast animal will have more fluid plasma membranes.

• The cells from the Mojave Desert animal will have a higher cholesterol concentration in the plasma membranes.

• The cells’ plasma membranes will be indistinguishable.

• The cells from the Mediterranean coast animal will have a higher glycoprotein content, while the cells from the Mojave Desert animal will have a higher lipoprotein content.

Water moves via osmosis _________.

• throughout the cytoplasm

• from an area with a high concentration of other solutes to a lower one

• from an area with a high concentration of water to one of lower concentration

• from an area with a low concentration of water to higher concentration

The principal force driving movement in diffusion is the __________.

• temperature

• particle size

• concentration gradient

• membrane surface area

What problem is faced by organisms that live in fresh water?

• Their bodies tend to take in too much water.

• They have no way of controlling their tonicity.

• Only salt water poses problems for animals that live in it.

• Their bodies tend to lose too much water to their environment.

In which situation would passive transport not use a transport protein for entry into a cell?

• water flowing into a hypertonic environment

• glucose being absorbed from the blood

• an ion flowing into a nerve cell to create an electrical potential

• oxygen moving into a cell after oxygen deprivation

Active transport must function continuously because __________.

• plasma membranes wear out

• not all membranes are amphiphilic

• facilitated transport opposes active transport

• diffusion is constantly moving solutes in opposite directions

How does the sodium-potassium pump make the interior of the cell negatively charged?

• by expelling anions

• by pulling in anions

• by expelling more cations than are taken in

• by taking in and expelling an equal number of cations