Question 1

The lactose permease transports lactose into the cell along with a(n)______________.

Accepted Answer

H⁺ (proton)

Question 2

When an uncharged molecule moves from a concentration of 10-4M to 10-2M,is the process spontaneous,at equilibrium,or does it require an input of energy?

Accepted Answer

A)  spontaneous 
B)  at equilibrium 
C)  input of energy required 
D)  It depends on the membrane potential. 
E)  None of the answers is correct. 
A)  spontaneous 
B)  at equilibrium 
C)  input of energy required 
D)  It depends on the membrane potential. 
E)  None of the answers is correct. C

Question 3

In a cell-to-cell junction,12 molecules of what protein form the gap junction?

Accepted Answer

A)  actin 
B)  keratin 
C)  connexin 
D)  tubulin 
E)  None of the answers is correct. 
A)  actin 
B)  keratin 
C)  connexin 
D)  tubulin 
E)  None of the answers is correct. C

Question 4

Channels that open in response to membrane depolarization are called __________ channels.

Accepted Answer

A)  voltage-gated 
B)  symport 
C)  ligand-gated 
D)  ion-gated 
E)  None of the answers is correct. 
A)  voltage-gated 
B)  symport 
C)  ligand-gated 
D)  ion-gated 
E)  None of the answers is correct.

Question 5

What is another name for a nerve impulse?

Accepted Answer

A)  action impulse 
B)  action potential 
C)  ion potential 
D)  ion impulse 
E)  None of the answers is correct. 
A)  action impulse 
B)  action potential 
C)  ion potential 
D)  ion impulse 
E)  None of the answers is correct.

Question 6

What family of transport proteins possesses a separate domain or cassette that specifically binds ATP?

Accepted Answer

A)  glucose transporters 
B)  Na+-K+ ATPase 
C)  ABC proteins 
D)  bicarbonate transporters 
E)  None of the answers is correct. 
A)  glucose transporters 
B)  Na+-K+ ATPase 
C)  ABC proteins 
D)  bicarbonate transporters 
E)  None of the answers is correct.

Question 7

A P-glycoprotein transporter is also referred to as MDR protein,which is an acronym for _________________________.

Accepted Answer

multidrug-

Question 8

Multidrug resistance in tumor cells is

Accepted Answer

A)  due to the action of a membrane pump that transports small molecules out of the cells. 
B)  the development of resistance to several drugs following an initial resistance to a single drug. 
C)  caused by a mutation in the cystic fibrosis gene. 
D)  due to the action of a membrane pump that transports small molecules out of the cells and the development of resistance to several drugs following an initial resistance to a single drug. 
E)  All of the answers are correct. 
A)  due to the action of a membrane pump that transports small molecules out of the cells. 
B)  the development of resistance to several drugs following an initial resistance to a single drug. 
C)  caused by a mutation in the cystic fibrosis gene. 
D)  due to the action of a membrane pump that transports small molecules out of the cells and the development of resistance to several drugs following an initial resistance to a single drug. 
E)  All of the answers are correct.

Question 9

Aquaporins are found in high levels in all of the following tissues except

Accepted Answer

A)  the kidneys. 
B)  salivary glands. 
C)  the cornea. 
D)  red blood cells. 
E)  the liver. 
A)  the kidneys. 
B)  salivary glands. 
C)  the cornea. 
D)  red blood cells. 
E)  the liver.

Question 10

Many pumps are members of the P-type ATPases.If you discovered a new enzyme with similar function,what reaction intermediate would help convince you that your enzyme was a member of this family?

Accepted Answer

The members of this family tra

Question 11

ABC transporters utilize ____________ to accomplish active transport.

Accepted Answer

The answer of ABC transporters utilize ____________ to accomplish active...

Question 12

Which of the following is NOT correct concerning the ABC proteins?

Accepted Answer

A)  They undergo conformational changes upon ATP binding. 
B)  All are also members of the P-loop NTPase superfamily. 
C)  The ATP-binding domains are referred to as ATP-binding cassettes. 
D)  They transfer a phosphate to a conserved Asp residue. 
E)  They are all true statements. 
A)  They undergo conformational changes upon ATP binding. 
B)  All are also members of the P-loop NTPase superfamily. 
C)  The ATP-binding domains are referred to as ATP-binding cassettes. 
D)  They transfer a phosphate to a conserved Asp residue. 
E)  They are all true statements.

Question 13

Where are gap junctions found?

Accepted Answer

A)  between nerve cells 
B)  in plasma membranes of apposed cells 
C)  in the synaptic cleft 
D)  between the ER and Golgi apparatus 
E)  None of the answers is correct. 
A)  between nerve cells 
B)  in plasma membranes of apposed cells 
C)  in the synaptic cleft 
D)  between the ER and Golgi apparatus 
E)  None of the answers is correct.

Question 14

What technique is used to measure conductance across a membrane?

Accepted Answer

A)  osmotic flow analysis 
B)  electron crystallography 
C)  stop-flow 
D)  patch-clamp 
E)  None of the answers is correct. 
A)  osmotic flow analysis 
B)  electron crystallography 
C)  stop-flow 
D)  patch-clamp 
E)  None of the answers is correct.

Question 15

___________________ are an important class of channels that increase the rate at which water flows through membranes.

Accepted Answer

The answer of ___________________ are an important class of channels...

Question 16

What is the function of selectivity filter amino acids in an ion channel?

Accepted Answer

A)  They close the channel pore after ion passage. 
B)  They determine the preference for a particular ion. 
C)  They limit the number of ions passing through the channel. 
D)  They make sure that only positively charged ions move through the channel 
E)  None of the answers is correct. 
A)  They close the channel pore after ion passage. 
B)  They determine the preference for a particular ion. 
C)  They limit the number of ions passing through the channel. 
D)  They make sure that only positively charged ions move through the channel 
E)  None of the answers is correct.

Question 17

Which of the following is correct concerning the sarcoplasmic reticulum Ca2+ ATPase?

Accepted Answer

A)  It is an example of an ABC transporter that interconverts between closed and open forms. 
B)  It transports Ca2+ from the sarcoplasmic reticulum into the cytoplasm. 
C)  This P-type ATPase maintains a calcium ion concentration of approximately 0.1 $\mu$M in the cytosol and 1.5 mM in the sarcoplasmic reticulum. 
D)  One Ca2+ is transported for each ATP hydrolyzed. 
E)  None of the answers is correct. 
A)  It is an example of an ABC transporter that interconverts between closed and open forms. 
B)  It transports Ca2+ from the sarcoplasmic reticulum into the cytoplasm. 
C)  This P-type ATPase maintains a calcium ion concentration of approximately 0.1 $\mu$M in the cytosol and 1.5 mM in the sarcoplasmic reticulum. 
D)  One Ca2+ is transported for each ATP hydrolyzed. 
E)  None of the answers is correct.

Question 18

What clues provided evidence of the mechanism of channel inactivation?

Accepted Answer

A)  Trypsin digestion of the cytoplasmic side caused the channel to stay open. 
B)  Protein mutants have different inactivation kinetics. 
C)  Inactivation could be restored by the addition of part of a missing peptide. 
D)  A and B 
E)  All of the answers are correct. 
A)  Trypsin digestion of the cytoplasmic side caused the channel to stay open. 
B)  Protein mutants have different inactivation kinetics. 
C)  Inactivation could be restored by the addition of part of a missing peptide. 
D)  A and B 
E)  All of the answers are correct.

Question 19

Describe the acetylcholine receptor shape.

Accepted Answer

The acetylcholine receptor is a tetramer

Question 20

How does energy affect the functioning of the Na+-K+ ATPase?

Accepted Answer

ATP provides the energy for th

Exam 13: Membrane Channels and Pumps

The lactose permease transports lactose into the cell along with a(n)______________.

When an uncharged molecule moves from a concentration of 10-4M to 10-2M,is the process spontaneous,at equilibrium,or does it require an input of energy?

In a cell-to-cell junction,12 molecules of what protein form the gap junction?

Channels that open in response to membrane depolarization are called __________ channels.

What is another name for a nerve impulse?

What family of transport proteins possesses a separate domain or cassette that specifically binds ATP?

A P-glycoprotein transporter is also referred to as MDR protein,which is an acronym for _________________________.

Multidrug resistance in tumor cells is

Aquaporins are found in high levels in all of the following tissues except

Many pumps are members of the P-type ATPases.If you discovered a new enzyme with similar function,what reaction intermediate would help convince you that your enzyme was a member of this family?

ABC transporters utilize ____________ to accomplish active transport.

Which of the following is NOT correct concerning the ABC proteins?

Where are gap junctions found?

What technique is used to measure conductance across a membrane?

___________________ are an important class of channels that increase the rate at which water flows through membranes.

What is the function of selectivity filter amino acids in an ion channel?

Which of the following is correct concerning the sarcoplasmic reticulum Ca2+ ATPase?

What clues provided evidence of the mechanism of channel inactivation?

Describe the acetylcholine receptor shape.

How does energy affect the functioning of the Na+-K+ ATPase?

Biochemistry: An Evolving Science

Protein Composition and Structure

Exploring Proteins and Proteomes

DNA, RNA, and the Flow of Genetic Information

Exploring Genes and Genomes

Exploring Evolution and Bioinformatics

Hemoglobin: a Portrait of a Protein in Action

Enzymes: Basic Concepts and Kinetics

Catalytic Strategies

Regulatory Strategies

Carbohydrates

Lipids and Cell Membranes

Signal-Transduction Pathways

Metabolism: Basic Concepts and Design

Glycolysis and Gluconeogenesis

The Citric Acid Cycle

Oxidative Phosphorylation

The Light Reactions of Photosynthesis

The Calvin Cycle and the Pentose Phosphate Pathway

Glycogen Metabolism

Fatty Acid Metabolism

Protein Turnover and Amino Acid Catabolism

The Biosynthesis of Amino Acids

Nucleotide Biosynthesis

Biosynthesis of Membrane Lipids and Steroids

The Integration of Metabolism

DNA Replication, repair, and Recombination

RNA Synthesis and Processing

Protein Synthesis

The Control of Gene Expression in Prokaryotes

The Control of Gene Expression in Eukaryotes

Sensory Systems

The Immune System

Molecular Motors

Drug Development

Filters

When an uncharged molecule moves from a concentration of 10^-4M to 10^-2M,is the process spontaneous,at equilibrium,or does it require an input of energy?

Which of the following is correct concerning the sarcoplasmic reticulum Ca²⁺ ATPase?

How does energy affect the functioning of the Na⁺-K⁺ ATPase?