Question 1

Match between columns Premises: Voltage-gated K⁺ channels also open immediately in response to local depolarization, reducing the magnitude of the action potential.
Voltage-gated Na⁺ channels become automatically inactivated shortly after opening, which ensures that the action potential cannot move backward along the axon.
Action potentials are usually mediated by voltage-gated Ca²⁺ channels. Neurotransmitters are small molecules released into the synaptic cleft after the fusion of synaptic vesicles with the presynaptic membrane.

Accepted Answer

The Answer of True and False is...

Question 2

The stimulation of a motor neuron ultimately results in the release of a neurotransmitter at the synapse between the neuron and a muscle cell.What type of neurotransmitter is used at these neuromuscular junctions?

Accepted Answer

A) acetylcholine 
B) glutamate 
C) GABA 
D) glycine

Question 3

Approximately, how many distinct synapses are established on the dendrites and cell body of a motor neuron in the spinal cord?

Accepted Answer

A) tens 
B) hundreds 
C) thousands 
D) millions

Question 4

Which of the following gated ion channels are involved in inhibitory synaptic signaling?

Accepted Answer

A) voltage-gated Na+ channels 
B) voltage-gated Ca2+ channels 
C) glycine-gated Cl− channels 
D) glutamate-gated cation channels

Question 5

The field of neurobiology is seeing rapid advances in our understanding of neural circuitry in the brain.Part of this work involves the physical mapping of all synapses (a project dubbed the connectome); another critical advance is in the area of optogenetics, which allows scientists to dissect neural circuits that determine specific behaviors in a range of organisms from fruit flies to monkeys.
A.Describe the method of optogenetics.
B.Optogenetics has great potential for deepening our understanding of behavior, learning, memory, and cognitive development.However, it is not as likely to be used directly for treatment of problems such as depression or anxiety.Why not? Consider the limitations of the method when answering this question.

Accepted Answer

The answer of The field of neurobiology is seeing rapid...

Question 6

You have generated antibodies that recognize the extracellular domain of the Ca2+-pump.Adding these antibodies to animal cells blocks the active transport of Ca2+ from the cytosol into the extracellular environment.What do you expect to observe with respect to intracellular Ca2+?

Accepted Answer

A) Ca2+-pumps in vesicle membranes keep cytosolic calcium levels low. 
B) Ca2+-pumps in the endoplasmic reticulum membrane keep cytosolic calcium levels low. 
C) Ca2+-pumps in the Golgi apparatus keep cytosolic calcium levels low. 
D) Ca2+ concentrations in the cytosol increase at a steady rate.

Question 7

Negatively charged ions are required to balance the net positive charge from metal ions such as K+, Na+, and Ca2+.Which of the following negatively charged ions is the most abundant outside the cell and which ion most often neutralize (written in parentheses)?

Accepted Answer

A) Cl− (Ca2+) 
B) PO43− (K+) 
C) PO43− (Ca2+) 
D) Cl− (Na+)

Question 8

Describe the two components of an electrochemical gradient.Use your description to suggest which of the following is influenced by a larger electrochemical gradient: (1) Na⁺ moving into the cell; (2) K⁺ moving out of the cell.Explain your reasoning.

Accepted Answer

The answer of Describe the two components of an electrochemical...

Question 9

Cells use membranes to help maintain set ranges of ion concentrations inside and outside the cell.Which of the following ions is the most abundant inside a typical mammalian cell?

Accepted Answer

A) Na+ 
B) K+ 
C) Ca2+ 
D) Cl−

Question 10

Identify the molecule in each pair that is more likely to diffuse through the lipid bilayer. A.amino acids or benzene B.Cl⁻ or ethanol C.glycerol or RNA D.H₂O or O₂ E.adenosine or ATP

Accepted Answer

The answer of Identify the molecule in each pair that...

Question 11

Which of the following occur WITHOUT coupling transport of the solute to the movement of a second solute?

Accepted Answer

A) import of glucose into gut epithelial cells 
B) export of Ca2+ from the cytosol 
C) export of H+ from animal cells for pH regulation 
D) the export of Na+ from cells to maintain resting membrane potential

Question 12

Which of the following statements about GABA receptors is FALSE?

Accepted Answer

A) They are located on postsynaptic membranes. 
B) They are ligand-gated channels. 
C) They inhibit synaptic signaling. 
D) They promote neuronal uptake of Na+.

Question 13

The movement of glucose into the cell, against its concentration gradient, can be powered by the co-transport of Na⁺ into the cell.Explain the thermodynamic factors governing this transporter.Under what conditions would transport of glucose slow or come to a halt?

Accepted Answer

The answer of The movement of glucose into the cell,...

Question 14

Pumps are transporters that are able to harness energy provided by other components in the cells to drive the movement of solutes across membranes, against their concentration gradient.This type of transport is called

Accepted Answer

A) active transport. 
B) free diffusion. 
C) facilitated diffusion. 
D) passive transport.

Question 15

Although the extracellular environment has a high sodium ion concentration and the intracellular environment has a high potassium ion concentration, both must be neutralized by negatively charged molecules.In the extracellular case, what is the principal anion?

Accepted Answer

A) HCO3− 
B) Cl− 
C) PO43− 
D) OH−

Question 16

Studies on the squid giant axon were instrumental to our current understanding of how action potentials are generated.You decide to do some experiments on the squid giant axon yourself. A.You remove the cytoplasm in an axon and replace it with an artificial cytoplasm that contains twice the normal concentration of K⁺ by adding KOAc, where OAc⁻ is an anion to which the membrane is impermeable.In this way, you double the internal concentration of K⁺ while maintaining the bulk electrical balance of the cytoplasmic solution.Will this make the resting potential of the membrane more or less negative? B.You add NaCl to the extracellular fluid and effectively double the amount of extracellular Na⁺ ions.How does this affect the action potential? C.You replace half of the NaCl in the extracellular fluid with choline chloride.(Choline is a monovalent cation much larger than Na⁺.Note that the presence of choline will not impede the flow of Na⁺ through its channels.) How will this affect the action potential?

Accepted Answer

The answer of Studies on the squid giant axon were...

Question 17

Match between columns Premises: Gap junctions are large pores that connect the cytosol to the extracellular space. The ion selectivity of a channel depends solely on the charge of the amino acids lining the pore inside the channel.
Most ion channels are gated, which allows them to open and close in response to a specific stimulus, rather than allowing the constant, unregulated flow of ions.
Aquaporin channels are found in the plasma membrane, and allow the rapid passage of water molecules and small ions in and out of cells.

Accepted Answer

The Answer of False and True is...

Question 18

Which of the following best describes the behavior of a gated channel?

Accepted Answer

A) It stays open continuously when stimulated. 
B) It opens more frequently in response to a given stimulus. 
C) It opens more widely as the stimulus becomes stronger. 
D) It requires a stimulus to change from closed to open.

Question 19

If ATP production is blocked in an animal cell, the cell will swell up.Explain this observation.

Accepted Answer

The answer of If ATP production is blocked in an...

Question 20

When the net charge on either side of the plasma membrane is zero, what else is true?

Accepted Answer

A) There is an equal number of K+ ions on each side of the plasma membrane. 
B) The K+ leak channels are open. 
C) The electrochemical potential across the membrane is zero. 
D) The resting membrane potential is between −20 mV and −200 mV.

Exam 12: Transport Across Cell Membranes

Indicate whether the statements below are TRUE or FALSE.If a statement is false, explain why it is false.

The stimulation of a motor neuron ultimately results in the release of a neurotransmitter at the synapse between the neuron and a muscle cell.What type of neurotransmitter is used at these neuromuscular junctions?

Approximately, how many distinct synapses are established on the dendrites and cell body of a motor neuron in the spinal cord?

Which of the following gated ion channels are involved in inhibitory synaptic signaling?

You have generated antibodies that recognize the extracellular domain of the Ca²⁺-pump.Adding these antibodies to animal cells blocks the active transport of Ca²⁺ from the cytosol into the extracellular environment.What do you expect to observe with respect to intracellular Ca²⁺?

Negatively charged ions are required to balance the net positive charge from metal ions such as K⁺, Na⁺, and Ca²⁺.Which of the following negatively charged ions is the most abundant outside the cell and which ion most often neutralize (written in parentheses) ?

Describe the two components of an electrochemical gradient.Use your description to suggest which of the following is influenced by a larger electrochemical gradient: (1) Na⁺ moving into the cell; (2) K⁺ moving out of the cell.Explain your reasoning.

Cells use membranes to help maintain set ranges of ion concentrations inside and outside the cell.Which of the following ions is the most abundant inside a typical mammalian cell?

Identify the molecule in each pair that is more likely to diffuse through the lipid bilayer. A.amino acids or benzene B.Cl⁻ or ethanol C.glycerol or RNA D.H₂O or O₂ E.adenosine or ATP

Which of the following occur WITHOUT coupling transport of the solute to the movement of a second solute?

Which of the following statements about GABA receptors is FALSE?

The movement of glucose into the cell, against its concentration gradient, can be powered by the co-transport of Na⁺ into the cell.Explain the thermodynamic factors governing this transporter.Under what conditions would transport of glucose slow or come to a halt?

Pumps are transporters that are able to harness energy provided by other components in the cells to drive the movement of solutes across membranes, against their concentration gradient.This type of transport is called

Although the extracellular environment has a high sodium ion concentration and the intracellular environment has a high potassium ion concentration, both must be neutralized by negatively charged molecules.In the extracellular case, what is the principal anion?

Indicate whether the statements below are TRUE or FALSE. If a statement is false, explain why it is false.

Which of the following best describes the behavior of a gated channel?

If ATP production is blocked in an animal cell, the cell will swell up.Explain this observation.

When the net charge on either side of the plasma membrane is zero, what else is true?

Exam 12: Transport Across Cell Membranes

Indicate whether the statements below are TRUE or FALSE.If a statement is false, explain why it is false.

The stimulation of a motor neuron ultimately results in the release of a neurotransmitter at the synapse between the neuron and a muscle cell.What type of neurotransmitter is used at these neuromuscular junctions?

Approximately, how many distinct synapses are established on the dendrites and cell body of a motor neuron in the spinal cord?

Which of the following gated ion channels are involved in inhibitory synaptic signaling?

You have generated antibodies that recognize the extracellular domain of the Ca2+-pump.Adding these antibodies to animal cells blocks the active transport of Ca2+ from the cytosol into the extracellular environment.What do you expect to observe with respect to intracellular Ca2+?

Negatively charged ions are required to balance the net positive charge from metal ions such as K+, Na+, and Ca2+.Which of the following negatively charged ions is the most abundant outside the cell and which ion most often neutralize (written in parentheses) ?

Describe the two components of an electrochemical gradient.Use your description to suggest which of the following is influenced by a larger electrochemical gradient: (1) Na+ moving into the cell; (2) K+ moving out of the cell.Explain your reasoning.

Cells use membranes to help maintain set ranges of ion concentrations inside and outside the cell.Which of the following ions is the most abundant inside a typical mammalian cell?

Identify the molecule in each pair that is more likely to diffuse through the lipid bilayer. A.amino acids or benzene B.Cl− or ethanol C.glycerol or RNA D.H2O or O2 E.adenosine or ATP

Which of the following occur WITHOUT coupling transport of the solute to the movement of a second solute?

Which of the following statements about GABA receptors is FALSE?

The movement of glucose into the cell, against its concentration gradient, can be powered by the co-transport of Na+ into the cell.Explain the thermodynamic factors governing this transporter.Under what conditions would transport of glucose slow or come to a halt?

Pumps are transporters that are able to harness energy provided by other components in the cells to drive the movement of solutes across membranes, against their concentration gradient.This type of transport is called

Although the extracellular environment has a high sodium ion concentration and the intracellular environment has a high potassium ion concentration, both must be neutralized by negatively charged molecules.In the extracellular case, what is the principal anion?

Indicate whether the statements below are TRUE or FALSE. If a statement is false, explain why it is false.

Which of the following best describes the behavior of a gated channel?

If ATP production is blocked in an animal cell, the cell will swell up.Explain this observation.

When the net charge on either side of the plasma membrane is zero, what else is true?

You have generated antibodies that recognize the extracellular domain of the Ca²⁺-pump.Adding these antibodies to animal cells blocks the active transport of Ca²⁺ from the cytosol into the extracellular environment.What do you expect to observe with respect to intracellular Ca²⁺?

Negatively charged ions are required to balance the net positive charge from metal ions such as K⁺, Na⁺, and Ca²⁺.Which of the following negatively charged ions is the most abundant outside the cell and which ion most often neutralize (written in parentheses) ?

Describe the two components of an electrochemical gradient.Use your description to suggest which of the following is influenced by a larger electrochemical gradient: (1) Na⁺ moving into the cell; (2) K⁺ moving out of the cell.Explain your reasoning.

Identify the molecule in each pair that is more likely to diffuse through the lipid bilayer. A.amino acids or benzene B.Cl⁻ or ethanol C.glycerol or RNA D.H₂O or O₂ E.adenosine or ATP

The movement of glucose into the cell, against its concentration gradient, can be powered by the co-transport of Na⁺ into the cell.Explain the thermodynamic factors governing this transporter.Under what conditions would transport of glucose slow or come to a halt?