Deck 8: Transport Across Membranes: Overcoming the Permeability Barrier

Question 1

You wish to dehydrate a piece of meat using solutions of varying salt concentrations. The best concentration to use would be

A)1%.
B)0.09%.
C)10%.
D)0.9%.
E)0.01%.

Answer 1

C

Question 2

Facilitated diffusion implies that energy in which form is NOT required?

A)Na+
B)glucose
C)oxygen
D)light
E)ATP

Answer 2

E

Question 3

Base your answers to the questions on the following information:
For a particular cell, the concentration of sucrose is 10 mM on the inside of the cell and 0.5 mM on the outside, whereas the concentration of sodium ions (Na+)is 0.5 mM on the inside of the cell and 10 mM on the outside. The membrane potential is - 150 mV, and the temperature is 25°C.
Constants: R = 1.987 cal/mol degree; T = 25°C = 298 K; F = 23,062 cal/mole volt
What would be the net OG' for the coupling of these two reactions?

A)- 3.459 kcal/mol
B)- 1.774 kcal/mol
C)+3.459 kcal/mol
D)- 7.007 kcal/mol
E)+7.007 kcal/mol

Answer 3

A

Question 4

The bacteriorhodopsin proton pump creates a proton gradient necessary in the process of anoxygenic photosynthesis. The energy necessary to drive this pump is generated by

A)light energy.
B)GTP hydrolysis.
C)ATP hydrolysis.
D)the rhodopsin pigment directly.
E)the proton gradient itself.

Question 5

An example of indirect active transport is

A)P- type ATPases.
B)Na+/K+ pumps.
C)ABC- type ATPases.
D)Na+/glucose symport.
E)both choice B and C

Question 6

One mechanism by which ions are specifically transported into the cell is the

A)alternating conformation model.
B)uniport transport model.
C)carrier protein transport.
D)gated channel.
E)all of the above

Question 7

The type of ATPases associated with the integral binding of ATP as part of the transport process is the

A)V type.
B)F type.
C)ABC type.
D)P type.

Question 8

Which of the following is NOT a characteristic of passive transport?

A)The energy for transport is generated by the molecular bonds of the substance being transported.
B)It is specific for the molecule being transported.
C)It requires binding of the molecule to be transported.
D)Transport of the substance is the result of a conformational change.
E)The energy for transport is generated by the gradient of the substance being transported.

Question 9

Animal cells use exocytosis to secrete all of the following EXCEPT

A)cell wall material.
B)milk proteins.
C)peptide hormones.
D)mucus.
E)digestive enzymes.

Question 10

In bacteria, the porins have the unique ability to transport

A)any molecule, regardless of properties or size.
B)hydrophobic molecules of a particular size.
C)all hydrophilic molecules.
D)all hydrophobic molecules.
E)hydrophilic molecules of a particular size.

Question 11

Which of the following is NOT a characteristic of active transport?

A)sensitive to metabolic poisons
B)can be coupled with passive transport to generate the energy necessary for active transport
C)can work as symports or antiports
D)exclusively move one molecule at a time in a unidirectional manner
E)all of the above

Question 12

Cystic fibrosis is the result of a malfunction of the cell in transporting which of the following ions?

A)Cl-
B)OH-
C)Na+
D)K+
E)glucose

Question 13

Mutations in bacterial porins can lead to antibiotic resistance typically by

A)closing the a- helix of the porin.
B)limiting the passage of nonpolar substances.
C)disrupting the voltage of the gated channel.
D)blocking entry of the antibiotic.
E)all of the above

Question 14

When transporting charged molecules across a membrane, which of the following is/are TRUE?

A)Keq is always equal to zero.
B)When moving chloride ions in nerve cells, the movement is with both concentration and electrochemical gradients.
C)OG° is always equal to one.
D)Membrane potential is not a factor.
E)OG is dependent on electrochemical potential.

Question 15

Which of the following are NOT mechanisms of active transport?

A)ATP hydrolysis- driven pump
B)unidirectional movement with gradients
C)light- driven pumps
D)coupled transport
E)both C and D

Question 16

In the kidney, the specialized transport proteins that allow for very rapid fluid movement into or out of cells are known as

A)osmosins.
B)anion exchange proteins.
C)aquaporins.
D)porins.
E)ionophores.

Question 17

Which of the following is NOT an example of facilitated diffusion?

A)anion exchange protein
B)GluT1 glucose transporter
C)oxygen transport
D)ahannel proteins
E)aquaporins

Question 18

The primary difference between active transport and facilitated diffusion is that only in active transport

A)only water molecules move.
B)[S]high -[S]low.
C)[S]low -[S]high.
D)transporter proteins are required.
E)the concentration gradient provides the necessary energy for movement.

Question 19

Of the following molecules, which would NOT be expected to be moved across a membrane by simple diffusion?

A)glucose
B)oxygen
C)fatty acids
D)water
E)dimethylurea

Question 20

Base your answers to the questions below on the following information:
A cell biologist interested in the transport of calcium ions (Ca2+)across the plasma membrane of bacterial cells made the following measurements on bacterial cells at 25°C:
Vm = - 150 mV [Ca2+] inside = 20 mM [Ca2+] outside = 0.4 mM
What is the free energy change for the inward movement of calcium ions into the bacterial cell?

A)+4.6 kcal/mol; an exergonic reaction
B)- 4.6 kcal/mol; an endergonic reaction
C)- 4.6 kcal/mol; an exergonic reaction
D)+4.6 kcal/mol; an endergonic reaction
E)none of the above

Question 21

In examining glucose transport into a cell, the immediate phosphorylation of glucose following its entry into the cell

A)puts glucose into a form to be stored.
B)keeps the glucose from being transported back out of the cell.
C)allows the cell to maintain higher levels of glucose outside the cell.
D)puts glucose into a form for use in cellular respiration.
E)all of the above

Question 22

The Na+/K+ pump actively moves

A)3 Na+ in 2 K+ out.
B)3 Na+ out, 2 K+ in.
C)1 Na+ out, 1 K+ in.
D)2Na+ out, 3 K+ in.
E)2Na+ in, 3 K+ out.

Question 23

Receptor- mediated endocytosis involves vesicles with a special coat protein known as
.

Question 24

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

Question 25

Transmembrane movement of a substance against a concentration gradient is called
.

Question 26

When transporting uncharged molecules across the membrane, which of the following is/are FALSE?

A)OG is not dependent upon a gradient.
B)movement requires a transport protein.
C)OG° is always equal to zero.
D)Keq is always equal to one.
E)both choices A and B

Question 27

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

Question 28

The movement of water through a membrane, from an area of high concentration to an area of low concentration, is known as

A)photolysis.
B)passive transport.
C)active transport.
D)facilitated transport.
E)osmosis.

Question 29

Base your answers to the questions on the following information:
For a particular cell, the concentration of sucrose is 10 mM on the inside of the cell and 0.5 mM on the outside, whereas the concentration of sodium ions (Na+)is 0.5 mM on the inside of the cell and 10 mM on the outside. The membrane potential is - 150 mV, and the temperature is 25°C.
Constants: R = 1.987 cal/mol degree; T = 25°C = 298 K; F = 23,062 cal/mole volt
What is the OG' for the inward transport of sodium ions?

A)+5.233 kcal/mol; an exergonic reaction
B)- 5.233 kcal/mol; an exergonic reaction
C)- 5.233 kcal/mol; an endergonic reaction
D)+5.233 kcal/mol; an endergonic reaction
E)none of the above

Question 30

Transmembrane movement of a substance with a concentration gradient, with no involvement of membrane proteins, is called _.

Question 31

You are wanting to modify plant cells. With the procedure you are using, the plant cells must be in a plasmolyzed state. This means that the plant cells must be placed in a(n)

A)isotonic solution.
B)hypertonic solution.
C)basic solution.
D)acid solution.
E)hypotonic solution.

Question 32

Base your answers to the questions on the following information:
For a particular cell, the concentration of sucrose is 10 mM on the inside of the cell and 0.5 mM on the outside, whereas the concentration of sodium ions (Na+)is 0.5 mM on the inside of the cell and 10 mM on the outside. The membrane potential is - 150 mV, and the temperature is 25°C.
Constants: R = 1.987 cal/mol degree; T = 25°C = 298 K; F = 23,062 cal/mole volt
What is the OG' for the inward transport of sucrose?

A)+1.774 kcal/mol; an endergonic reaction
B)+1.774 kcal/mol; an exergonic reaction
C)- 1.774 kcal/mol; an exergonic reaction
D)- 1.774 kcal/mol; an endergonic reaction
E)none of the above

Question 33

Base your answers to the questions below on the following information:
A cell biologist interested in the transport of calcium ions (Ca2+)across the plasma membrane of bacterial cells made the following measurements on bacterial cells at 25°C:
Vm = - 150 mV [Ca2+] inside = 20 mM [Ca2+] outside = 0.4 mM
Assuming no change in either the internal or external calcium ion concentration, at what membrane potential would there be no net movement of calcium across the membrane?

A)0 mV
B)+50 mV
C)+25 mV
D)- 50 mV
E)- 25 mV

Question 34

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

Question 35

Which of the following is/are TRUE with regard to water movement in osmosis?

A)hypotonic -hypertonic
B)hypertonic -hypotonic
C)hypertonic -isotonic
D)isotonic -hypotonic
E)both choices C and D