Question 1

5-HT3 receptors and nAChRs share which of these properties?

Accepted Answer

A)  The ligand that binds to them 
B)  Which ion(s) they conduct 
C)  Heterogeneity of subunits comprising them 
D)  Their expression in both vertebrate and invertebrate nervous systems 
E)  Their expression in both skeletal muscle and the nervous system cells 
A)  The ligand that binds to them 
B)  Which ion(s) they conduct 
C)  Heterogeneity of subunits comprising them 
D)  Their expression in both vertebrate and invertebrate nervous systems 
E)  Their expression in both skeletal muscle and the nervous system cells

Question 2

Where is the ion selectivity filter located, considering the quaternary structure of a representative, well-studied ion channel like KCS?

Accepted Answer

A)  The outer vestibule of the channel, which is approximately 2 nm in diameter 
B)  Adjacent to short helices and their neighboring residues, which form a box-like structure at the channel's extracellular face 
C)  Within the central pore 
D)  Within the lower pore 
E)  By the inner helix, which predominantly forms the narrowest part of the channel structure 
A)  The outer vestibule of the channel, which is approximately 2 nm in diameter 
B)  Adjacent to short helices and their neighboring residues, which form a box-like structure at the channel's extracellular face 
C)  Within the central pore 
D)  Within the lower pore 
E)  By the inner helix, which predominantly forms the narrowest part of the channel structure

Question 3

Describe three experimental observations that led to our current understanding of conformational changes of Cys-loop receptors that allow current to flow.

Accepted Answer

First, plunge freezing demonstrated that

Question 4

Explain how -helices and β-sheets contribute to the specific tertiary and quaternary structural features of Cys-loop receptors like nAChR?

Accepted Answer

-helices form the transmembran

Question 5

What senses membrane potential in voltage-activated channels?

Accepted Answer

A)  Arginine and lysine residues on the S4 transmembrane segment 
B)  Glycosylation sites ubiquitous on the α-subunit 
C)  Auxiliary β-subunits 
D)  The moderately hydrophobic P-loop region 
E)  Positively charged residues of the S6 transmembrane segment 
A)  Arginine and lysine residues on the S4 transmembrane segment 
B)  Glycosylation sites ubiquitous on the α-subunit 
C)  Auxiliary β-subunits 
D)  The moderately hydrophobic P-loop region 
E)  Positively charged residues of the S6 transmembrane segment

Question 6

How do gain of function mutations to Scn9a (NaV 1.7) lead to hyperalgesia (excessive or spurious pain)?

Accepted Answer

Gain of function mutations to Na_V 1.7 (Sc

Question 7

A mammal senses painful heat on its skin. Which is the most likely channel transducing the stimulus?

Accepted Answer

A)  Piezo 2 
B)  TRPV1 
C)  TRPM8 
D)  Kir 
E)  NaV 1.7 
A)  Piezo 2 
B)  TRPV1 
C)  TRPM8 
D)  Kir 
E)  NaV 1.7

Question 8

Which type of information below helped determine the subunit composition and stoichiometry of nAChRs?

Accepted Answer

A)  Position of ligand binding sites at α-γ and α-δ interfaces 
B)  Affinity for α-bungarotoxin 
C)  Electron imaging and other physical techniques 
D)  Molecular weight of the purified Torpedo nAChR and its constituent subunits 
E)  More diameter and relative selectivity of large cations 
A)  Position of ligand binding sites at α-γ and α-δ interfaces 
B)  Affinity for α-bungarotoxin 
C)  Electron imaging and other physical techniques 
D)  Molecular weight of the purified Torpedo nAChR and its constituent subunits 
E)  More diameter and relative selectivity of large cations

Question 9

ACh, the ligand, only binds to at -subunits, which are 2 of the 5 subunits that comprise a nAChR yet conformational changes occur throughout its tertiary and quaternary structure. Why?

Accepted Answer

A)  Ligands span between αγ and αγ-subunits so in fact 4 of the 5 subunits are affected. 
B)  Subunits interact via amino acid chains connecting their intramembrane regions, so movement in one subunit influences the others too. 
C)  β-subunits drive movement for all other subunits exclusively via M2-M3 connecting loops. 
D)  Via subunits tilting away from the axis of the receptor. 
E)  Regardless of how many ligands bind, all subunits have M2 helices that move within the membrane. 
A)  Ligands span between αγ and αγ-subunits so in fact 4 of the 5 subunits are affected. 
B)  Subunits interact via amino acid chains connecting their intramembrane regions, so movement in one subunit influences the others too. 
C)  β-subunits drive movement for all other subunits exclusively via M2-M3 connecting loops. 
D)  Via subunits tilting away from the axis of the receptor. 
E)  Regardless of how many ligands bind, all subunits have M2 helices that move within the membrane.

Question 10

Replacing a codon for one amino acid with another one prior to translation is an example of

Accepted Answer

A)  gene transcription. 
B)  glycosylation. 
C)  RNA editing. 
D)  alternative splicing. 
E)  post-translational modification. 
A)  gene transcription. 
B)  glycosylation. 
C)  RNA editing. 
D)  alternative splicing. 
E)  post-translational modification.

Question 11

With regard to ion channel opening, the M1 ligand-binding domain of Cys-loop receptors functionally corresponds to which of the following regions of voltage-activated ion channels?

Accepted Answer

A)  S1 transmembrane domain 
B)  S1-S4 in its entirety 
C)  S4 transmembrane domain 
D)  S5-S6, which form the P-loop 
E)  S6 transmembrane uniquely 
A)  S1 transmembrane domain 
B)  S1-S4 in its entirety 
C)  S4 transmembrane domain 
D)  S5-S6, which form the P-loop 
E)  S6 transmembrane uniquely

Question 12

Deafness is associated with genetic knockout of which gene?

Accepted Answer

A)  Transmembrane Channel-like Protein 1 (TMC1) 
B)  Transmembrane Channel-like Protein 2 (TMC2) 
C)  Tetraspan Membrane Protein of Hair Cell Cilia (TMHS) 
D)  Transmembrane Inner Ear Protein (TMI
E)  
E)  Both TMC1 and TMC2 
A)  Transmembrane Channel-like Protein 1 (TMC1) 
B)  Transmembrane Channel-like Protein 2 (TMC2) 
C)  Tetraspan Membrane Protein of Hair Cell Cilia (TMHS) 
D)  Transmembrane Inner Ear Protein (TMI
E)  
E)  Both TMC1 and TMC2

Question 13

Make an argument for how the W897X mutation of NaV 1.7 (Scn9a) ion channels leads to "painless" persons who show no ability to perceive pain.

Accepted Answer

The W897X mutation to Na_V 1.7 (Scn9a) can

Question 14

Piezo 1 is likely to transduce which of the following stimuli or senses?

Accepted Answer

A)  Sound (pitch) 
B)  Body orientation (position with respect to gravity) 
C)  Touch (e.g., pressure applied to the skin) 
D)  Interoception 
E)  Heat 
A)  Sound (pitch) 
B)  Body orientation (position with respect to gravity) 
C)  Touch (e.g., pressure applied to the skin) 
D)  Interoception 
E)  Heat

Question 15

Evaluate the evidence that S4 transmembrane domain of voltage-activated sodium channels moves tangent to the plane of the membrane in response to depolarization.

Accepted Answer

When amino acids at either end of the S4

Question 16

Charged amino acid residues located at cytoplasmic and extracellular surfaces of the receptor

Accepted Answer

A)  enable homomultimeric α7 channels even when other subunit isotypes are not present. 
B)  influence affinity for the bound ligand. 
C)  influence channel open time. 
D)  govern cation or anion selectivity of the channel. 
E)  govern ligand selectivity (e.g., serotonin, glutamate, γ-aminobutyric acid, glycine, or zinc). 
A)  enable homomultimeric α7 channels even when other subunit isotypes are not present. 
B)  influence affinity for the bound ligand. 
C)  influence channel open time. 
D)  govern cation or anion selectivity of the channel. 
E)  govern ligand selectivity (e.g., serotonin, glutamate, γ-aminobutyric acid, glycine, or zinc).

Question 17

A mammal is drinking cold water from a stream Which is the most likely channel transducing the stimulus?

Accepted Answer

A)  Piezo 2 
B)  TRPV1 
C)  TRPM8 
D)  Kir 
E)  NaV 1.7 
A)  Piezo 2 
B)  TRPV1 
C)  TRPM8 
D)  Kir 
E)  NaV 1.7

Question 18

Which of the following ligands gates inhibitory synaptic transmission in vertebrate and invertebrate nervous systems?

Accepted Answer

A)  Serotonin 
B)  γ-aminobutyric acid 
C)  Glycine 
D)  γ-aminobutyric acid and glycine 
E)  Zinc 
A)  Serotonin 
B)  γ-aminobutyric acid 
C)  Glycine 
D)  γ-aminobutyric acid and glycine 
E)  Zinc

Exam 5: Structure of Ion Channels

5-HT3 receptors and nAChRs share which of these properties?

Where is the ion selectivity filter located, considering the quaternary structure of a representative, well-studied ion channel like KCS?

Describe three experimental observations that led to our current understanding of conformational changes of Cys-loop receptors that allow current to flow.

Explain how -helices and β-sheets contribute to the specific tertiary and quaternary structural features of Cys-loop receptors like nAChR?

What senses membrane potential in voltage-activated channels?

How do gain of function mutations to Scn9a (NaV 1.7) lead to hyperalgesia (excessive or spurious pain)?

A mammal senses painful heat on its skin. Which is the most likely channel transducing the stimulus?

Which type of information below helped determine the subunit composition and stoichiometry of nAChRs?

ACh, the ligand, only binds to at -subunits, which are 2 of the 5 subunits that comprise a nAChR yet conformational changes occur throughout its tertiary and quaternary structure. Why?

Replacing a codon for one amino acid with another one prior to translation is an example of

With regard to ion channel opening, the M1 ligand-binding domain of Cys-loop receptors functionally corresponds to which of the following regions of voltage-activated ion channels?

Deafness is associated with genetic knockout of which gene?

Make an argument for how the W897X mutation of NaV 1.7 (Scn9a) ion channels leads to "painless" persons who show no ability to perceive pain.

Piezo 1 is likely to transduce which of the following stimuli or senses?

Evaluate the evidence that S4 transmembrane domain of voltage-activated sodium channels moves tangent to the plane of the membrane in response to depolarization.

Charged amino acid residues located at cytoplasmic and extracellular surfaces of the receptor

A mammal is drinking cold water from a stream Which is the most likely channel transducing the stimulus?

Which of the following ligands gates inhibitory synaptic transmission in vertebrate and invertebrate nervous systems?

Principles of Signaling and Organization

Signaling in the Visual System

Functional Architecture of the Visual Cortex

Ion Channels and Signaling

Ionic Basis of the Resting Potential

Ionic Basis of the Action Potential

Electrical Signaling in Neurons

Ion Transport Across Cell Membranes

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

Filters

5-HT₃ receptors and nAChRs share which of these properties?

Where is the ion selectivity filter located, considering the quaternary structure of a representative, well-studied ion channel like K_CS?

How do gain of function mutations to Scn9a (Na_V 1.7) lead to hyperalgesia (excessive or spurious pain)?

Make an argument for how the W897X mutation of Na_V 1.7 (Scn9a) ion channels leads to "painless" persons who show no ability to perceive pain.