Question 1

When does the NCX stop moving ions across the membrane?

Accepted Answer

A)  When the energy dissipated by sodium entry equals that associated with movement of calcium ions 
B)  When the resting membrane potential equals the reversal potential for calcium 
C)  When the driving force for sodium is different than 0 mV 
D)  When there is no net driving force for calcium 
E)  When there is not ATP 
A)  When the energy dissipated by sodium entry equals that associated with movement of calcium ions 
B)  When the resting membrane potential equals the reversal potential for calcium 
C)  When the driving force for sodium is different than 0 mV 
D)  When there is no net driving force for calcium 
E)  When there is not ATP A

Question 2

Which ion, in addition to protons, is cotransported into synaptic vesicles together with glutamate?

Accepted Answer

A)  Sodium 
B)  Chloride 
C)  Potassium 
D)  Calcium 
E)  GABA 
A)  Sodium 
B)  Chloride 
C)  Potassium 
D)  Calcium 
E)  GABA B

Question 3

How does reducing the extracellular sodium concentration increase the intracellular calcium concentration?

Accepted Answer

A)  By increasing passive calcium influx through the cell membrane 
B)  By reducing the activity of the NCX transport system 
C)  By hyperpolarizing the resting membrane potential 
D)  By inverting the electrochemical gradient for calcium 
E)  By inhibiting the activity of the Na+/K+ ATPase 
A)  By increasing passive calcium influx through the cell membrane 
B)  By reducing the activity of the NCX transport system 
C)  By hyperpolarizing the resting membrane potential 
D)  By inverting the electrochemical gradient for calcium 
E)  By inhibiting the activity of the Na+/K+ ATPase A

Question 4

What is the main function of chloride-bicarbonate exchangers?

Accepted Answer

Chloride-bicarbonate exchangers, togethe

Question 5

What is the first event for ion transport through the sodium-potassium exchange pump?

Accepted Answer

A)  Sodium binding to the inward-facing sites of the pump 
B)  Potassium binding to the inward-facing sites of the pump 
C)  Potassium binding to the outward-facing sites of the pump 
D)  ATP hydrolysis 
E)  ATP phosphorylation 
A)  Sodium binding to the inward-facing sites of the pump 
B)  Potassium binding to the inward-facing sites of the pump 
C)  Potassium binding to the outward-facing sites of the pump 
D)  ATP hydrolysis 
E)  ATP phosphorylation

Question 6

What is one of the main functional consequences of increasing cytoplasmic levels of calcium in muscle fibers?

Accepted Answer

A)  Trigger muscle relaxation 
B)  Prevent acetylcholine receptor activation 
C)  Inhibit action potential propagation 
D)  Speed up action potential propagation 
E)  Initiate muscle contraction 
A)  Trigger muscle relaxation 
B)  Prevent acetylcholine receptor activation 
C)  Inhibit action potential propagation 
D)  Speed up action potential propagation 
E)  Initiate muscle contraction

Question 7

What supplies the energy required for the inward chloride transport across the plasma cell membrane?

Accepted Answer

A)  The movement of potassium down its concentration gradient 
B)  The movement of sodium down its concentration gradient 
C)  ATP hydrolysis 
D)  The Na+/K+ ATPase 
E)  The sodium-calcium exchanger 
A)  The movement of potassium down its concentration gradient 
B)  The movement of sodium down its concentration gradient 
C)  ATP hydrolysis 
D)  The Na+/K+ ATPase 
E)  The sodium-calcium exchanger

Question 8

Why is GABA depolarizing in the immature brain?

Accepted Answer

Because the main chloride transporter ex

Question 9

Why is neurotransmitter uptake physiologically relevant?

Accepted Answer

Removing neurotransmitters from the extr

Question 10

How can the ion exchange mechanism of the NCX transport system be made to run backward?

Accepted Answer

By altering one or more of the ion gradi

Question 11

What drives secondary active transport?

Accepted Answer

A)  Metabolic energy 
B)  ATP 
C)  Ion flux down their electrochemical gradient 
D)  Osmotic pressure 
E)  Diffusion 
A)  Metabolic energy 
B)  ATP 
C)  Ion flux down their electrochemical gradient 
D)  Osmotic pressure 
E)  Diffusion

Question 12

What unique feature distinguishes GLYT2 glycine transporters from other members of the SLC6 family?

Accepted Answer

A)  It is only expressed in neurons. 
B)  It is only expressed in presynaptic terminals. 
C)  Its transport stoichiometry is three sodium to one chloride to one glycine. 
D)  It is only expressed in postsynaptic terminals. 
E)  It is only expressed extrasynaptically. 
A)  It is only expressed in neurons. 
B)  It is only expressed in presynaptic terminals. 
C)  Its transport stoichiometry is three sodium to one chloride to one glycine. 
D)  It is only expressed in postsynaptic terminals. 
E)  It is only expressed extrasynaptically.

Question 13

Why is the recovery of intracellular calcium concentration after calcium influx not influenced by membrane potential?

Accepted Answer

A)  Because the transport cycle of the plasma cell membrane calcium ATPase is electrogenic 
B)  Because the plasma cell membrane calcium ATPase has a high affinity for calcium 
C)  Because calcium binding to the plasma cell membrane calcium ATPase is voltage-dependent 
D)  Because the transport cycle of the plasma cell membrane calcium ATPase is electroneutral 
E)  Because the plasma cell membrane calcium ATPase has a low transport capacity 
A)  Because the transport cycle of the plasma cell membrane calcium ATPase is electrogenic 
B)  Because the plasma cell membrane calcium ATPase has a high affinity for calcium 
C)  Because calcium binding to the plasma cell membrane calcium ATPase is voltage-dependent 
D)  Because the transport cycle of the plasma cell membrane calcium ATPase is electroneutral 
E)  Because the plasma cell membrane calcium ATPase has a low transport capacity

Question 14

Which chloride transporter is transiently expressed in the immature brain?

Accepted Answer

A)  KCC2 
B)  NKCC1 
C)  NCX 
D)  NKCX 
E)  GLAST 
A)  KCC2 
B)  NKCC1 
C)  NCX 
D)  NKCX 
E)  GLAST

Question 15

What makes transporters electrogenic?

Accepted Answer

Their ability to transport une

Question 16

Why is the regulation of intracellular chloride concentration important in neurons?

Accepted Answer

Because, by regulating the ele

Question 17

How does reversed glutamate uptake affect brain function after brain damage by stroke or trauma?

Accepted Answer

A)  By preventing glutamate receptor activation 
B)  By promoting glutamate uptake in presynaptic terminals 
C)  By promoting glial cell death 
D)  By triggering excitotoxicity in the damaged area 
E)  Glutamate transporters can only transport glutamate towards the cell cytoplasm, not into the extracellular space. 
A)  By preventing glutamate receptor activation 
B)  By promoting glutamate uptake in presynaptic terminals 
C)  By promoting glial cell death 
D)  By triggering excitotoxicity in the damaged area 
E)  Glutamate transporters can only transport glutamate towards the cell cytoplasm, not into the extracellular space.

Question 18

Each of these is a vesicular neurotransmitter transporter except

Accepted Answer

A)  VMAT. 
B)  VAChT. 
C)  VGAT. 
D)  GAT. 
E)  VGLUT. 
A)  VMAT. 
B)  VAChT. 
C)  VGAT. 
D)  GAT. 
E)  VGLUT.

Question 19

How does the sequence of events underlying ion transport through the sodium-potassium exchange pump end?

Accepted Answer

A)  Dephosphorylation of the pump 
B)  Binding of sodium ions 
C)  Intracellular binding of potassium ions 
D)  Release of potassium ions into the cytoplasm 
E)  Opening of an aqueous pore in the protein 
A)  Dephosphorylation of the pump 
B)  Binding of sodium ions 
C)  Intracellular binding of potassium ions 
D)  Release of potassium ions into the cytoplasm 
E)  Opening of an aqueous pore in the protein

Question 20

Which fundamental feature distinguishes plasma membrane from endoplasmic and sarcoplasmic reticulum calcium ATPases?

Accepted Answer

The stoichiometry of the transport proce

Exam 9: Ion Transport Across Cell Membranes

When does the NCX stop moving ions across the membrane?

Which ion, in addition to protons, is cotransported into synaptic vesicles together with glutamate?

How does reducing the extracellular sodium concentration increase the intracellular calcium concentration?

What is the main function of chloride-bicarbonate exchangers?

What is the first event for ion transport through the sodium-potassium exchange pump?

What is one of the main functional consequences of increasing cytoplasmic levels of calcium in muscle fibers?

What supplies the energy required for the inward chloride transport across the plasma cell membrane?

Why is GABA depolarizing in the immature brain?

Why is neurotransmitter uptake physiologically relevant?

How can the ion exchange mechanism of the NCX transport system be made to run backward?

What drives secondary active transport?

What unique feature distinguishes GLYT2 glycine transporters from other members of the SLC6 family?

Why is the recovery of intracellular calcium concentration after calcium influx not influenced by membrane potential?

Which chloride transporter is transiently expressed in the immature brain?

What makes transporters electrogenic?

Why is the regulation of intracellular chloride concentration important in neurons?

How does reversed glutamate uptake affect brain function after brain damage by stroke or trauma?

Each of these is a vesicular neurotransmitter transporter except

How does the sequence of events underlying ion transport through the sodium-potassium exchange pump end?

Which fundamental feature distinguishes plasma membrane from endoplasmic and sarcoplasmic reticulum calcium ATPases?

Principles of Signaling and Organization

Signaling in the Visual System

Functional Architecture of the Visual Cortex

Ion Channels and Signaling

Structure of Ion Channels

Ionic Basis of the Resting Potential

Ionic Basis of the Action Potential

Electrical Signaling in Neurons

Properties and Functions of Neuroglial Cells

Mechanisms of Direct Synaptic Transmission

Indirect Mechanisms of Synaptic Transmission

Release of Neurotransmitters

Neurotransmitters in the Central Nervous System

Transmitter Synthesis, Storage, Transport, and Inactivation

Synaptic Plasticity

The Molecular and Cellular Biology of Synaptic Plasticity

Mechanisms of Extrasynaptic Communication

Autonomic Nervous System

Walking, Flying, and Swimming: Cellular Mechanisms of Sensorimotor Behavior in Invertebrates

Sensory Transduction

Transduction and Transmission in the Retina

Touch, Pain, and Texture Sensation

Auditory and Vestibular Sensation

Constructing Perception

Initiation and Control of Coordinated Muscular Movements

Development of the Nervous System

Critical Periods in Sensory Systems

Regeneration and Repair of Synaptic Connections After Injury

Appendix

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