Cell Biology: Practice Questions (Transport Across Membranes)

A(n) ________ solution is one that contains a solute concentration that is ________ than that within the cell and results in the "bursting" of the cell.

hypotonic; lower

In the kidney, the specialized transport proteins that allow for very rapid fluid movement into or out of cells are A) aquaporins. B) porins. C) ionophores. D) anion exchange proteins.

A

One mechanism by which ions are specifically transported into the cell is the A) gated channel. B) alternating model. C) carrier protein transport. D) uniport transport model.

A

The graph below shows the rate of transport for each substance when the cells are placed in 0.10 mM solutions of A, B, and C. Based on these data and coupled with the data observed above, substance C is transported via ________. Figure 8.2 A) active transport B) facilitated transport C) passive transport D) simple diffusion

A

Which of the following is not an example of facilitated diffusion? A) glucose transporter B) anion exchange protein C) aquaporins D) oxygen transport

A

Which type of ATPase is associated with the integral binding of ATP as part of the transport process? A) ABC type B) F type C) P type D) V type

A

Cystic fibrosis is the result of a malfunction of the cell in transporting which of the following ions? A) Cl- B) K+ C) Na+ D) glucose

A

A) diffusion and passive and active transport B) both passive and active transport C) diffusion D) active transport E) none of the listed processes F) both diffusion and passive transport G) indirect active transport H) passive transport 1) requires a specific integral membrane protein 2) dependent on solubility properties of the solute 3) requires cellular expenditure of energy 4) Keq = 1 5) Na+/glucose symport 6) Na+/K+ pump 7) only involves transfer of small, nonpolar molecules 8) applies only to ions 9) ΔG° = 0 10) direction transport depends on [gradient] any time 11) requires ligand binding and therefore Michaelis constants can be calculated

1) A 2) C 3) D 4) A 5) G 6) D 7) C 8) E 9) A 10) F 11) B

A special class of ABC-type ATPases associated with tumors that allow movement of antibiotics and other drugs out of the cell are known as A) multidrug resistance transport protein. B) import transporter proteins. C) cystic fibrosis transmembrane conductance regulatorA D) human catalytic convertase.

A

Animal cells use exocytosis to secrete all of the following except A) cell wall material. B) mucus. C) peptide hormones. D) milk proteins.

A

In bacteria, the porins have the unique ability to transport A) all hydrophilic . B) hydrophilic of a particular size. C) all hydrophobic D) hydrophobic of a size.

B

Mutations in bacterial porins can lead to antibiotic resistance typically by A) closing the α-helix of the porin. B) limiting the passage of nonpolar substances. C) blocking entry of the antibiotic. D) disrupting the voltage of the gated channel.

C

The primary difference between active transport and facilitated diffusion is that active transport is the only one in which A) [S]high → [S]low. B) transporter proteins are required. C) [S]low → [S]high. D) the concentration gradient provides the necessary energy for movement.

C

Which of the following is not a mechanism of active transport? A) coupled transport B) ATP hydrolysis-driven pump C) unidirectional with gradients D) light-driven pumps

C

A researcher is interested in the mode of transport across the cell membrane of three different substances: A, B, and C. His data are reported in the graphs associated with the following questions. The graph above shows the initial rate of transport for each substance when the cells are placed in solutions of different concentrations of A, B, and C. Based on these data, substance A is transported via A) active transport. B) facilitated transport. C) passive transport. D) simple diffusion.

D

An example of indirect active transport is A) Na+/K+ pumps. B) P-type ATPases. C) ABC-type ATPases. D) Na+/glucose symport.

D

Based on the same graph, substances B and C A) show saturation kinetics. B) are transported by a transporter protein. C) do not move by simple diffusion. D) all of the above

D

In all organisms, active transport across a membrane requires A) equal concentrations of ions on both sides of the membrane. B) a resting potential of 0 mV. C) exergonic movement indicated by the direction of the electrochemical potential. D) an asymmetric distribution of ions across a membrane.

D

In some cells, it was noted that water moved faster than could be accounted for by simple diffusion. From this information, which of the following were identified and characterized? A) hydroporins B) glycoporins C) facilitator porins D) aquaporins

D

Of the following molecules, which would not be expected to be moved across a membrane by simple diffusion? A) oxygen B) fatty acids C) water D) glucose

D

The Na+/K+ pump actively moves A) 2 Na+ in, 3 K+ out. B) 2 Na+ out, 3 K+ in. C) 3 Na+ in 2 K+ out. D) 3 Na+ out, 2 K+ in.

D

The bacteriorhodopsin proton pump creates a proton gradient that is needed in the process of anoxygenic photosynthesis. The energy necessary to drive this pump is generated by A) rhodopsin directly. B) the proton gradient itself. C) GTP hydrolysis. D) light energy.

D

The movement of water through a membrane, from an area of high concentration to an area of low concentration, is known as A) active transport. B) facilitated transport. C) passive transport. D) osmosis

D

Which of the following is not a characteristic of passive transport? A) It requires binding of the molecule to be transported. B) It is specific for the molecule being transported. C) The energy for transport is generated by the gradient of the substance being transported. D) The energy for transport is generated by the molecular bonds of the substance being transported.

D

You wish to dehydrate a piece of meat using solutions of varying salt concentrations. The best concentration is A) 0.01%. B) 0.09%. C) 0.9%. D) 10%.

D

The type of transport ATPase found in bacteria, mitochondria, and chloroplasts are the ________ ATPases

F-type

The type of transport ATPase that are reversibly phosphorylated as part of the transport mechanism are ____ ATPases.

P-type

Transmembrane movement of a substance against a concentration gradient is called

active transport

The transport of two molecules across the cell membrane in different directions is called

antiport

Transmembrane movement of a substance with a [gradient], with no involvement of membrane proteins, is

diffusion

Uptake of food particles by trapping them within an invagination of the plasma membrane is called

endocytosis

Transmembrane movement of a substance with a [gradient] utilizing a membrane protein is called

passive transport or facilitated transport

Pores of the outer membrane of bacteria, mitochondria, and chloroplasts that are less specific and are formed by multipass transmembrane proteins are

porins

The transport of two molecules across the cell membrane in the same direction is called

symport