Name Class Date s8

Name Class Date

SECTION 5-1 REVIEW

PASSIVE TRANSPORT

VOCABULARY REVIEW Explain the relationship between the terms in each of the following pairs of terms.

1. concentration gradient, diffusion

2. osmosis, turgor pressure

3. hypertonic, plasmolysis

MULTIPLE CHOICE Write the correct letter in the blank.

1. Substances that can pass through cell membranes by diffusion include

a. Na+ ions. b. CI- ions. c. glucose. d. oxygen.

2. The contractile vacuole of a paramecium should be active when the paramecium is in

a. an isotonic environment. c. a hypertonic environment.

b. a hypotonic environment. d. any environment.

3. When a human red blood cell is placed in a hypotonic environment, it will

a. undergo cytolysis. c. experience a decrease in turgor

pressure.

b. undergo plasmolysis. d. be at equilibrium.

4. Facilitated diffusion is often used to transport

a. ions. c. molecules that are not soluble in

lipids.

b. water. d. molecules that are too small to

diffuse across the membrane.

5. Na+ ions enter cells by

a. diffusing across the lipid c. binding to

bilayer without assistance Na+ carrier proteins.

b. diffusing through Na+ ion d. binding to CI- ions.

channels.

SHORT ANSWER Answer the questions in the space provided.

1. What happens to the movement of molecules at equilibrium?

2. How do carrier proteins transport substances across cell membranes?

3. What types of stimuli can cause the gates on ion channels to open or close?

4. Critical Thinking How does the interaction between a carrier protein and the substance it transports resemble the interaction between an enzyme and its substrate?

STRUCTURES AND FUNCTIONS The drawings below show the appearance of a red blood cell and a plant cell in isotonic, hypotonic, and hypertonic environments. Label each environment in the spaces provided.

SECTION 5-2 REVIEW

ACTIVE TRANSPORT

VOCABULARY REVIEW Define the following terms.

1. active transport

2. endocytosis

3. vesicle

4. phagocytosis

MULTIPLE CHOICE Write the correct letter in the blank.

1. Facilitated-diffusion carrier proteins and cell-membrane pumps both

a. require an input of c. transport substances up their energy. concentration gradients.

b. are specific for the kinds of d. carry out active transport.

substances they transport.

2. The sodium-potassium pump transports

a. Na+ out of the cell and K+ c. K+ out of the cell and Na+ into into the cell. the cell.

b. Na+ and K+ in both directions d. Na+ during some cycles and K+ across the cell membrane during other cycles.

3. The energy needed to power the sodium-potassium pump is provided by the

a. binding of ATP to the c. removal of a phosphate group pump. from ATP.

b. transport of ATP by the pump. d. formation of ATP.

4. Pinocytosis involves the transport of

a. large particles out of a cell. c. whole cells into another cell.

b. fluids into a cell. d. lysosomes out of a cell.

5. Exocytosis is a

a. type of passive transport.

b. mechanism by which cells ingest other cells.

c. transport process in which vesicles are formed from pouches in the cell membrane.

d. way for cells to release large molecules, such as proteins.

SHORT ANSWER Answer the questions in the space provided.

1. Why is the sodium-potassium transport mechanism called a “pump”?

2. Explain how a phagocyte destroys bacteria.

3. Describe how a cell produces and releases proteins.

4. Critical Thinking Why is it important that ions being transported across a cell membrane be shielded from the interior of the lipid bilayer?

STRUCTURES AND FUNCTIONS Use the figure to answer the following questions.

1. The diagrams below represent the six steps in one cycle of the sodium-potassium pump. The order of the steps has been scrambled. Beginning with diagram d (numbered 1), sequence the remaining diagrams by writing the appropriate numeral in each blank.

2. On which side of the membrane are Na+ ions released from the pump?

3. On which side of the membrane are K+ ions released from the pump?

Modern Biology 29 Passive Transport