Question 1

Label depolarization, repolarization, and hyperpolarization in Figure Q2-14.   Figure Q2-14

Accepted Answer

See Figure AHyperpolarization is more negative and depolarization is more positive. The first hyperpolarization and second depolarization could also be considered 'repolarization' as the voltage across the membrane is repolarizing back to rest.

Question 2

What is the size of the primary structure of K+ channels compared to Na+ channels?

Accepted Answer

A)  It is twice the size. 
B)  It is half the size. 
C)  It is one quarter the size. 
D)  It is four times the size. 
A)  It is twice the size. 
B)  It is half the size. 
C)  It is one quarter the size. 
D)  It is four times the size. C

Question 3

Label Figure Q2-29 with the following terms: action potential threshold, action potential, subthreshold stimulus, suprathreshold stimulus.   Figure Q2-29
B. In Figure Q2-29, stimulus 4 is of larger amplitude than stimulus 3. What happened to the action potential when a larger stimulus was provided and why?
C. In Figure Q2-29, what do you predict would happen if you increased the duration of stimulus 4?
How Do Electrical Signals Propagate from the Neuronal Cell Body to Its Axon Terminals?

Accepted Answer

A.The threshold is the voltage at which an action potential is generated. In Figure Ait is the point at which there are some 'failures' and a single action potential (2) The subthreshold stimulus refers to the current pulse stimulus that is given that does not generate an action potential. Either stimulus 1 or 2 are correct. The suprathreshold stimulus refers to any stimulus that generates an action potential. In this case, either of the last two stimuli is correct.   Figure A2-29
B. The rise time of the action potential is faster. This is because the larger current is able to activate more sodium channels, which brings the membrane potential to threshold faster by starting the regenerative process faster.
C. If you increase the duration of the stimulus, you will get more action potentials per unit time. If this is a neuron with different intrinsic membrane properties you may get different activity patterns, but the basic answer is an increase in frequency of action potentials.

Question 4

What is the function of the 'capacitor' in a neuron? Choose all that apply.

Accepted Answer

A)  Storage of charge across the membrane 
B)  To allow the movement of ions across the membrane 
C)  To provide the ability to integrate signals 
D)  To provide a delay in changes in voltage across the membrane 
A)  Storage of charge across the membrane 
B)  To allow the movement of ions across the membrane 
C)  To provide the ability to integrate signals 
D)  To provide a delay in changes in voltage across the membrane

Question 5

Figure Q2-37 shows a whole-cell sodium current (bottom trace) elicited by stepping the membrane potential from -70 mV to 0 mV (top trace). The dashed line is 0 nA. Upon depolarizing the membrane, there is an inward current. This whole-cell current is a reflection of the cumulative activity of many individual ion channels. What is the probable state of an individual sodium channel at each point (A, B, and C)?   Figure Q2-37

Accepted Answer

The sodium channels have a high probabil

Question 6

Figure Q2-42 shows a patch clamp recording from the Shaker channel (ShB). What is the presumed molecular mechanism for inactivation of the channel?   Figure Q2-42

Accepted Answer

A)  Several positively charged amino acids in S4 
B)  Several negatively charge amino acids in S4 
C)  The N-terminal 'ball-and-chain' 
D)  A block by Na+ ions 
A)  Several positively charged amino acids in S4 
B)  Several negatively charge amino acids in S4 
C)  The N-terminal 'ball-and-chain' 
D)  A block by Na+ ions

Question 7

If there is a large voltage across a membrane and a low resistance, is the current going to be larger or small?
B. In order to have a large current, if there is a large resistance what should the voltage difference be?

Accepted Answer

Knowing the equation I = V/R, if ΔV is l

Question 8

Figure Q2-10 shows an interpretive drawing of a microtubule moving rightward on a glass slide to which a substance purified from squid axoplasm had been immobilized, in the presence of ATP.   Figure Q2-10
A. What is the substance that was purified that allows movement of the microtubule?
B. What would happen if a non-hydrolyzable form of ATP was added to the solution?

Accepted Answer

Kinesin (although dynein would

Question 9

List in order of size: neurofilaments, microtubules, microfilaments.

Accepted Answer

Microfilam

Question 10

What is the transcription unit?

Accepted Answer

A)  The part of the gene that serves as a template for RNA synthesis 
B)  The part of RNA that serves as a template for protein synthesis 
C)  The part of the gene that serves as a template for protein synthesis 
D)  The unit of RNA that is made from a particular gene 
A)  The part of the gene that serves as a template for RNA synthesis 
B)  The part of RNA that serves as a template for protein synthesis 
C)  The part of the gene that serves as a template for protein synthesis 
D)  The unit of RNA that is made from a particular gene

Question 11

Proteins that are destined for export from the cell or that are inserted into the lipid bilayer are synthesized in/on which organelle?

Accepted Answer

A)  Free ribosomes 
B)  Endoplasmic reticulum 
C)  Golgi apparatus 
D)  Nucleus 
A)  Free ribosomes 
B)  Endoplasmic reticulum 
C)  Golgi apparatus 
D)  Nucleus

Question 12

Which equation is used to determine the equilibrium potential of any ion?

Accepted Answer

A)  Ohm's law 
B)  The driving force 
C)  The Nernst potential 
D)  The Goldman-Hodgkin-Katz equation 
A)  Ohm's law 
B)  The driving force 
C)  The Nernst potential 
D)  The Goldman-Hodgkin-Katz equation

Question 13

In order to test the hypothesis that the rising phase of the action potential is caused by Na+ influx, researchers recorded the magnitude of the action potential when in a normal solution (like sea water) and then again after increasing the extracellular Na+ concentration. What do you predict will happen to the action potential with the increased extracellular Na+ concentration and why? Draw the action potential on Figure Q2-30.   Figure Q2-30

Accepted Answer

The action potential amplitude increased

Question 14

What is the function of endocytosis? Choose all that are correct.

Accepted Answer

A)  To take proteins to the plasma membrane 
B)  To take proteins away from the plasma membrane 
C)  Potential degradation of proteins 
D)  To secrete proteins from the cell 
A)  To take proteins to the plasma membrane 
B)  To take proteins away from the plasma membrane 
C)  Potential degradation of proteins 
D)  To secrete proteins from the cell

Question 15

Using the voltage clamp technique, Hodgkin and Huxley found an early inward current and a later outer current (Figure Q2-32, recorded current). What would happen to the current if you would apply tetrodotoxin to the bath before changing the voltage across the membrane? Please select between currents A and B and explain your answer.   Figure Q2-32

Accepted Answer

Tetrodotoxin blocks voltage-de

Question 16

The structure of the selectivity filter is known.
A. Why are the electronegative carbonyl groups important for K+ to move across the filter?
B. How do electrostatic forces of K+ ions help move K+ across the filter?

Accepted Answer

They carbonyl groups mimic the stabiliza

Question 17

Figure Q2-38 shows the response of a single Na+ channel patch clamp recording. Which individual ion channel state best describes the current in A, B, and C?   Figure Q2-38

Accepted Answer

Closed
B.

Question 18

According to the Goldman-Hodgkin-Katz equation, if the membrane were more permeable to Na+ at rest, instead of K+, what would the approximate resting membrane potential be?

Accepted Answer

A)  -70 mV 
B)  +50mV 
C)  -79 mV 
D)  +100mV 
A)  -70 mV 
B)  +50mV 
C)  -79 mV 
D)  +100mV

Question 19

Why do action potentials usually travel unidirectionally down an axon?

Accepted Answer

A)  Delayed activation of K+ channels 
B)  Inactivation of Na+ channels 
C)  Myelin prevents travel in the opposite direction. 
D)  Action potentials are all-or-none. 
A)  Delayed activation of K+ channels 
B)  Inactivation of Na+ channels 
C)  Myelin prevents travel in the opposite direction. 
D)  Action potentials are all-or-none.

Question 20

Invertebrates and vertebrates have evolved different strategies to change the length/space constant (λ) of a neuron. For each strategy, say whether this increases or decreases the length constant and what property in the following equation it influences. $\lambda = \sqrt { d R _ { m } / 4 R _ { i } }$ A. Invertebrates increased the diameter of the axon.
B. Vertebrates use myelination of the axon.

Accepted Answer

This increases the length constant by de

Label depolarization, repolarization, and hyperpolarization in Figure Q2-14. Figure Q2-14

What is the size of the primary structure of K⁺ channels compared to Na⁺ channels?

What is the function of the 'capacitor' in a neuron? Choose all that apply.

Figure Q2-42 shows a patch clamp recording from the Shaker channel (ShB). What is the presumed molecular mechanism for inactivation of the channel? Figure Q2-42

If there is a large voltage across a membrane and a low resistance, is the current going to be larger or small? B. In order to have a large current, if there is a large resistance what should the voltage difference be?

List in order of size: neurofilaments, microtubules, microfilaments.

What is the transcription unit?

Proteins that are destined for export from the cell or that are inserted into the lipid bilayer are synthesized in/on which organelle?

Which equation is used to determine the equilibrium potential of any ion?

What is the function of endocytosis? Choose all that are correct.

The structure of the selectivity filter is known. A. Why are the electronegative carbonyl groups important for K⁺ to move across the filter? B. How do electrostatic forces of K⁺ ions help move K⁺ across the filter?

Figure Q2-38 shows the response of a single Na⁺ channel patch clamp recording. Which individual ion channel state best describes the current in A, B, and C? Figure Q2-38

According to the Goldman-Hodgkin-Katz equation, if the membrane were more permeable to Na⁺ at rest, instead of K⁺, what would the approximate resting membrane potential be?

Why do action potentials usually travel unidirectionally down an axon?

An Invitation to Neurobiology

Signaling Across Synapses

Vision

Wiring of the Visual System

Olfaction, Taste, Audition, and Somatosensation

Wiring of the Nervous System

Motor and Regulatory Systems

Sexual Behavior

Memory, Learning, and Synaptic Plasticity

Brain Disorders

Evolution of the Nervous System

Ways of Exploring

Filters

Exam 2: Signaling Within Neurons

Label depolarization, repolarization, and hyperpolarization in Figure Q2-14. Figure Q2-14

What is the size of the primary structure of K+ channels compared to Na+ channels?

What is the function of the 'capacitor' in a neuron? Choose all that apply.

Figure Q2-42 shows a patch clamp recording from the Shaker channel (ShB). What is the presumed molecular mechanism for inactivation of the channel? Figure Q2-42

If there is a large voltage across a membrane and a low resistance, is the current going to be larger or small? B. In order to have a large current, if there is a large resistance what should the voltage difference be?

List in order of size: neurofilaments, microtubules, microfilaments.

What is the transcription unit?

Proteins that are destined for export from the cell or that are inserted into the lipid bilayer are synthesized in/on which organelle?

Which equation is used to determine the equilibrium potential of any ion?

What is the function of endocytosis? Choose all that are correct.

The structure of the selectivity filter is known. A. Why are the electronegative carbonyl groups important for K+ to move across the filter? B. How do electrostatic forces of K+ ions help move K+ across the filter?

Figure Q2-38 shows the response of a single Na+ channel patch clamp recording. Which individual ion channel state best describes the current in A, B, and C? Figure Q2-38

According to the Goldman-Hodgkin-Katz equation, if the membrane were more permeable to Na+ at rest, instead of K+, what would the approximate resting membrane potential be?

Why do action potentials usually travel unidirectionally down an axon?

An Invitation to Neurobiology

Signaling Across Synapses

Vision

Wiring of the Visual System

Olfaction, Taste, Audition, and Somatosensation

Wiring of the Nervous System

Motor and Regulatory Systems

Sexual Behavior

Memory, Learning, and Synaptic Plasticity

Brain Disorders

Evolution of the Nervous System

Ways of Exploring

Filters

What is the size of the primary structure of K⁺ channels compared to Na⁺ channels?

The structure of the selectivity filter is known. A. Why are the electronegative carbonyl groups important for K⁺ to move across the filter? B. How do electrostatic forces of K⁺ ions help move K⁺ across the filter?

Figure Q2-38 shows the response of a single Na⁺ channel patch clamp recording. Which individual ion channel state best describes the current in A, B, and C? Figure Q2-38

According to the Goldman-Hodgkin-Katz equation, if the membrane were more permeable to Na⁺ at rest, instead of K⁺, what would the approximate resting membrane potential be?