Question 1

Extracellular messengers binding on surface receptors may exert effects on cells via all the following means, except:

Accepted Answer

A)   opening gated channels.
B)   opening a gated channel through activation of a G protein.
C)   activation of the adenylyl cyclase system.
D)   binding to sites and then being endocytized.
E)   ultimately activating protein kinases.

Question 2

____________________ are connecting tunnels in gaps between adjacent cells.

Accepted Answer

The answer of ____________________ are connecting tunnels in gaps between...

Question 3

With active transport, ATP energy is used in the phosphorylation-dephosphorylation cycle of the carrier.

Accepted Answer

A) True 
 B)False

Question 4

The primary barrier to passage of water-soluble substances across the plasma membrane is the outer layer of carbohydrates.

Accepted Answer

A) True 
 B)False

Question 5

In a water solution containing dissolved salt:

Accepted Answer

A)   salt is the solute
B)   water is the solute
C)   salt is the solvent
D)   the solute is stationary
E)   the solution is heterogeneous

Question 6

Indicate which characteristic of a mediated-transport system is referred to in each item by filling in the blank using the following answer code:
-If in the presence of substance Z there is a decreased rate of entry of substance X, what characteristic is being exemplified?

Accepted Answer

A)  specificity
B)  saturation
C)  competition

Question 7

Phospholipids

Accepted Answer

A)   consist of a polar, hydrophilic, phosphate-bearing, head and two nonpolar hydrophobic, fatty-acid tails.
B)   are aligned in a lipid bilayer in membranes.
C)   serve as carrier molecules.
D)   only (a)  and (b)  above.
E)   all of these answers.

Question 8

If a concentration or electrical gradient is present for a given substance, the substance will always passively permeate the membrane.

Accepted Answer

A) True 
 B)False

Question 9

Facilitated diffusion

Accepted Answer

A)   involves a carrier molecule.
B)   requires energy expenditure.
C)   is how water enters the cells.
D)   both (a)  and (c)  above.
E)   all of these answers.

Question 10

Movement of K+ into the cell requires energy expenditure, whereas movement of Na+ into the cell does not.

Accepted Answer

A) True 
 B)False

Question 11

Potassium movement into cells always requires energy expenditure.

Accepted Answer

A) True 
 B)False

Question 12

The following questions refer to comparative concentrations, permeabilities, and potentials under various circumstances. Indicate the relationship between the two items listed in each situation by following answer code.
-A. permeability of a resting nerve cell membrane to K?
B. permeability of a resting nerve cell membrane to Na?

Accepted Answer

A)  A is greater than B
B)  B is greater than A
C)  A and B are equal

Question 13

Indicate the various roles of the following ions:
-anion to which the membrane is impermeable

Accepted Answer

A)  Na+
B)  K+
C)  A-
D)  Cl-

Question 14

____________________ refers to a separation of opposite charges across the membrane.

Accepted Answer

The answer of ____________________ refers to a separation of opposite...

Question 15

At resting membrane potential

Accepted Answer

A)   the membrane is more permeable to K+ than to Na+.
B)   the membrane is more permeable to Na+ than to K+.
C)   Cl- is at its equilibrium potential.
D)   both (a)  and (c)  above.
E)   both (b)  and (c)  above.

Question 16

____________________ are the cells that secrete the majority of the composition of the extracellular matrix.

Accepted Answer

The answer of ____________________ are the cells that secrete the...

Question 17

The sodium-potassium pump moves ____ sodium ions out of the cell for every 2 potassium ions it moves into the cell.

Accepted Answer

A)   3
B)   5
C)   7
D)   11
E)   13

Question 18

Which of the following moves across the membrane by facilitated diffusion?

Accepted Answer

A)   oxygen
B)   sodium
C)   glucose
D)   potassium
E)   water

Question 19

The resting membrane potential of a typical neuron is more negative then the equilibrium potential for potassium.

Accepted Answer

A) True 
 B)False

Question 20

Which statement regarding membrane proteins is incorrect?

Accepted Answer

A)   channels are water-filled pathways.
B)   channels maybe highly selective.
C)   membrane proteins may catalyze specific reactions.
D)   CAMs serve as binding sites for specific ligands.
E)   proteins may work in conjunction with carbohydrates to provide recognition of "self."

Exam 3: The Plasma Membrane and Membrane Potential

The sodium-potassium pump moves ____ sodium ions out of the cell for every 2 potassium ions it moves into the cell.

Correct Answer
verified

If a concentration or electrical gradient is present for a given substance, the substance will always passively permeate the membrane.

Correct Answer
verified

Extracellular messengers binding on surface receptors may exert effects on cells via all the following means, except:

Correct Answer
verified

____________________ are the cells that secrete the majority of the composition of the extracellular matrix.

Correct Answer
verified

Correct Answer
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Phospholipids

Correct Answer
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Potassium movement into cells always requires energy expenditure.

Correct Answer
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____________________ refers to a separation of opposite charges across the membrane.

Correct Answer
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Indicate which characteristic of a mediated-transport system is referred to in each item by filling in the blank using the following answer code: -If in the presence of substance Z there is a decreased rate of entry of substance X, what characteristic is being exemplified?

Correct Answer
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With active transport, ATP energy is used in the phosphorylation-dephosphorylation cycle of the carrier.

Correct Answer
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In a water solution containing dissolved salt:

Correct Answer
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At resting membrane potential

Correct Answer
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Indicate the various roles of the following ions: -anion to which the membrane is impermeable

Correct Answer
verified

Facilitated diffusion

Correct Answer
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Movement of K⁺ into the cell requires energy expenditure, whereas movement of Na⁺ into the cell does not.

Correct Answer
verified

The primary barrier to passage of water-soluble substances across the plasma membrane is the outer layer of carbohydrates.

Correct Answer
verified

The resting membrane potential of a typical neuron is more negative then the equilibrium potential for potassium.

Correct Answer
verified

Which statement regarding membrane proteins is incorrect?

Correct Answer
verified

____________________ are connecting tunnels in gaps between adjacent cells.

Correct Answer
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Which of the following moves across the membrane by facilitated diffusion?

Correct Answer
verified

Exam 3: The Plasma Membrane and Membrane Potential

The sodium-potassium pump moves ____ sodium ions out of the cell for every 2 potassium ions it moves into the cell.

Correct AnswerverifiedShow Answer

If a concentration or electrical gradient is present for a given substance, the substance will always passively permeate the membrane.

Correct AnswerverifiedShow Answer

Extracellular messengers binding on surface receptors may exert effects on cells via all the following means, except:

Correct AnswerverifiedShow Answer

____________________ are the cells that secrete the majority of the composition of the extracellular matrix.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Phospholipids

Correct AnswerverifiedShow Answer

Potassium movement into cells always requires energy expenditure.

Correct AnswerverifiedShow Answer

____________________ refers to a separation of opposite charges across the membrane.

Correct AnswerverifiedShow Answer

Indicate which characteristic of a mediated-transport system is referred to in each item by filling in the blank using the following answer code: -If in the presence of substance Z there is a decreased rate of entry of substance X, what characteristic is being exemplified?

Correct AnswerverifiedShow Answer

With active transport, ATP energy is used in the phosphorylation-dephosphorylation cycle of the carrier.

Correct AnswerverifiedShow Answer

In a water solution containing dissolved salt:

Correct AnswerverifiedShow Answer

At resting membrane potential

Correct AnswerverifiedShow Answer

Indicate the various roles of the following ions: -anion to which the membrane is impermeable

Correct AnswerverifiedShow Answer

Facilitated diffusion

Correct AnswerverifiedShow Answer

Movement of K+ into the cell requires energy expenditure, whereas movement of Na+ into the cell does not.

Correct AnswerverifiedShow Answer

The primary barrier to passage of water-soluble substances across the plasma membrane is the outer layer of carbohydrates.

Correct AnswerverifiedShow Answer

The resting membrane potential of a typical neuron is more negative then the equilibrium potential for potassium.

Correct AnswerverifiedShow Answer

Which statement regarding membrane proteins is incorrect?

Correct AnswerverifiedShow Answer

____________________ are connecting tunnels in gaps between adjacent cells.

Correct AnswerverifiedShow Answer

Which of the following moves across the membrane by facilitated diffusion?

Correct AnswerverifiedShow Answer

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Movement of K⁺ into the cell requires energy expenditure, whereas movement of Na⁺ into the cell does not.

Correct Answer
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