Question 1

Which of the following has the fastest rate of transport?

Accepted Answer

A)  Channel-mediated diffusion 
B)  Facilitated diffusion 
C)  Active transport 
D)  All of the above are equally fast.

Question 2

Channels that open in response to neurotransmitters or other signal molecules are called _______ channels.

Accepted Answer

A)  voltage-gated 
B)  ligand-gated 
C)  signal-gated 
D)  ion

Question 3

Membrane proteins are able to move

Accepted Answer

A)  from the inner to the outer surface of a membrane. 
B)  laterally within the plane of a membrane. 
C)  from apical to basal surfaces of intestinal epithelial cells. 
D)  only if attached to microtubules or microfilaments.

Question 4

Two examples of membrane lipids that are present in small amounts are

Accepted Answer

A)  cholesterol and phosphatidylcholine. 
B)  glycolipids and phosphatidylinositol. 
C)  phosphatidylcholine and sphingomyelin. 
D)  phosphatidylethanolamine and phosphatidylserine.

Question 5

The released neurotransmitters at a synapse are sensed by _______-gated channels.

Accepted Answer

The answer of The released neurotransmitters at a synapse are...

Question 6

Active transport differs from facilitated diffusion in that

Accepted Answer

A)  ions are not transported via active transport, only by facilitated diffusion. 
B)  active transport requires a protein component, whereas facilitated diffusion occurs by simple diffusion through the plasma membrane. 
C)  active transport involves the transport of molecules up their concentration gradient. 
D)  active transport involves a conformational change in the transport molecule.

Question 7

Mutations in the internalization signal of endocytic receptors prevent their interaction with

Accepted Answer

A)  adaptor proteins. 
B)  caveolin. 
C)  clathrin. 
D)  dynamin.

Question 8

Estrogen is an example of a hormone to which the plasma membrane is impermeable.

Accepted Answer

A) True 
 B)False

Question 9

The selectivity filter in a K⁺ channel is able to _______ K⁺ but not Na⁺, which is smaller.

Accepted Answer

The answer of The selectivity filter in a K⁺ channel...

Question 10

LDL uptake by cells is one of the functions of

Accepted Answer

A)  receptor-mediated endocytosis. 
B)  phagocytosis. 
C)  caveolae. 
D)  ABC transporters.

Question 11

The membrane-spanning portion of the protein porin (and proteins with similar structures in the outer membranes of mitochondria and chloroplasts) has a membrane-spanning secondary structure called a(n) _______.

Accepted Answer

The answer of The membrane-spanning portion of the protein porin...

Question 12

What are peripheral membrane proteins?

Accepted Answer

The answer of What are peripheral membrane proteins?...

Question 13

The resting plasma membrane potential as described by the Nernst equation is the sum of the movement of many ions. However, in practice, the movement of _______, a single ion, is the major component determining membrane potential.

Accepted Answer

A)  Ca2+ 
B)  Cl- 
C)  K+ 
D)  Na+

Question 14

Voltage-sensitive K+ channels are 1,000 times more permeable to K+ than to Na+ because

Accepted Answer

A)  K+ ions are smaller than Na+ ions. 
B)  K+ ions have a lower charge density than Na+ ions. 
C)  a selectivity filter removes the water molecules from K+ ions but not from Na+ ions. 
D)  K+ ions are more concentrated inside the cell than outside the cell.

Question 15

A feature common to most transmembrane proteins is a(n)

Accepted Answer

A)  phosphorylated exterior domain. 
B)  $\alpha$-helical region of about 20 to 25 hydrophobic amino acids. 
C)  amino acid sequence rich in acidic residues. 
D)  structure consisting almost exclusively of $\beta$-sheets.

Question 16

The apical surface of intestinal epithelial cells is covered by a carbohydrate coat known as the glycocalyx.

Accepted Answer

A) True 
 B)False

Question 17

The flow of which ion makes the largest contribution to the resting potential?

Accepted Answer

A)  K+ 
B)  Na+ 
C)  H+ 
D)  Ca2+

Question 18

Define endocytosis and explain the process by which it operates.

Accepted Answer

The answer of Define endocytosis and explain the process by...

Question 19

Glycolipids are the major lipids in the plasma membrane.

Accepted Answer

A) True 
 B)False

Question 20

How does water enter a cell from the extracellular space?

Accepted Answer

The answer of How does water enter a cell from...

Exam 15: The Plasma Membrane

Which of the following has the fastest rate of transport?

Channels that open in response to neurotransmitters or other signal molecules are called _______ channels.

Membrane proteins are able to move

Two examples of membrane lipids that are present in small amounts are

The released neurotransmitters at a synapse are sensed by _______-gated channels.

Active transport differs from facilitated diffusion in that

Mutations in the internalization signal of endocytic receptors prevent their interaction with

Estrogen is an example of a hormone to which the plasma membrane is impermeable.

The selectivity filter in a K⁺ channel is able to _______ K⁺ but not Na⁺, which is smaller.

LDL uptake by cells is one of the functions of

The membrane-spanning portion of the protein porin (and proteins with similar structures in the outer membranes of mitochondria and chloroplasts) has a membrane-spanning secondary structure called a(n) _______.

What are peripheral membrane proteins?

The resting plasma membrane potential as described by the Nernst equation is the sum of the movement of many ions. However, in practice, the movement of _______, a single ion, is the major component determining membrane potential.

Voltage-sensitive K⁺ channels are 1,000 times more permeable to K⁺ than to Na⁺ because

A feature common to most transmembrane proteins is a(n)

The apical surface of intestinal epithelial cells is covered by a carbohydrate coat known as the glycocalyx.

The flow of which ion makes the largest contribution to the resting potential?

Define endocytosis and explain the process by which it operates.

Glycolipids are the major lipids in the plasma membrane.

How does water enter a cell from the extracellular space?

Exam 15: The Plasma Membrane

Which of the following has the fastest rate of transport?

Channels that open in response to neurotransmitters or other signal molecules are called _______ channels.

Membrane proteins are able to move

Two examples of membrane lipids that are present in small amounts are

The released neurotransmitters at a synapse are sensed by _______-gated channels.

Active transport differs from facilitated diffusion in that

Mutations in the internalization signal of endocytic receptors prevent their interaction with

Estrogen is an example of a hormone to which the plasma membrane is impermeable.

The selectivity filter in a K+ channel is able to _______ K+ but not Na+, which is smaller.

LDL uptake by cells is one of the functions of

The membrane-spanning portion of the protein porin (and proteins with similar structures in the outer membranes of mitochondria and chloroplasts) has a membrane-spanning secondary structure called a(n) _______.

What are peripheral membrane proteins?

The resting plasma membrane potential as described by the Nernst equation is the sum of the movement of many ions. However, in practice, the movement of _______, a single ion, is the major component determining membrane potential.

Voltage-sensitive K+ channels are 1,000 times more permeable to K+ than to Na+ because

A feature common to most transmembrane proteins is a(n)

The apical surface of intestinal epithelial cells is covered by a carbohydrate coat known as the glycocalyx.

The flow of which ion makes the largest contribution to the resting potential?

Define endocytosis and explain the process by which it operates.

Glycolipids are the major lipids in the plasma membrane.

How does water enter a cell from the extracellular space?

The selectivity filter in a K⁺ channel is able to _______ K⁺ but not Na⁺, which is smaller.

Voltage-sensitive K⁺ channels are 1,000 times more permeable to K⁺ than to Na⁺ because