Neurobiology-Final

in the plasma membrane, ion channels can be associated with these electric-cicuit components:

Resistors

the ion current that flows through a voltage-gated ion channel

1. is described by ohms law 2. depends on the equilibrium potential of the ion 4. is determined by the resistance of the channel 5. depends on the ion's driving force

label A through D

1. resting membrane potential 2. depolarization phase 3. repolarization phase 4. hyperpolarization

event 4

Ca2+ activates proteins on the surface. of synaptic vesiclles

event 3

Ca2+ enter into the cell through voltage-gated Ca2+ channels

which of the following ions are necessary for the exocytosis of neurotransmitter?

Ca2+ ions

in the plasma membrane, the phospholibid bilater can be associated with these electric-circuit components:

Capacitators

the GABAa receptor is permeable to:

Cl- ions

what would you do to prolong the duration of the repolarization phase of an action potential?

Decrease the outflow of K+ ions

the Golgi-staining technique allows one to visualized only the soma of a neuron

False

compared to non-myelinated axons, conduction velocity in myelinated axon is:

Faster because myelinated axons exhibit saltatory conduction

broadening the duration of the repolarizing phase of the action potential would cause:

Greater amount of neurotransmitter is released

which of these equations describe a calcium current?

ICa=gCa x (Vm-ECa)

which of these equations describes a potassium current?

Ik=gk x (Vm-Ek)

which of the following enzymes are shared by the synthetic pathways of dopamine, adrenaline and noradrenaline?

L-dihydroxy-phenylalanine (dopa) decarboxylase tyrosine hydroxylase

which unit is used to measure the membrane resistance of a cell?

Megaohm (MΩ)

event 7

Neurotransmitter diffuses across the synaptic cleft and binds to the receptors on the postsynaptic membrane

which of the following factors determine the amount of neurotransmitter release at the level of the presynaptic terminal?

Number of vesicles released in the synaptic cleft

Cutting the dorsal root of a spinal nerve would cause:

loss of sensation

which unit is used to emasure the resting membrane potential?

millivolt (mV)

Which of these cellular components are abundant in the presynaptic terminal?

mitochondria

Glutamate bings an AMPA postsynaptic receptor. the resting membrane pot of the postsynaptic cell is -65mV. which of the following is correct?

more Na+ enters than K+ exits teh cell and there is net depolarization

Cutting the ventral root of a spinal nerve would cause

muscle paralysis

which unit is used to measure ion currents?

nanoampere (nA)

the resting membrane potential of a typical neuron is:

negative because, at rest, the membrane is mainly permeable to K+ ions

ffor the ACh recepetors in the neuromuscular junction, which is the correct combination of agonists and antagonists?

nicotine, curare

which if the following receptors produce excitatory postsynaptic potentials

nicotinic receptor AMPA receptor NMDA receptor

which of the following ligand-gated membrane receptors are blocked by curare?

nicotinic receptors

which tyoe if ion channel is blocked by tetrodotoxin? a. voltage gated Ca2+ channel b. ligand-gated Cl- channel c. ligan gated K+ channel d. voltage gated K+ channel e. none of the above

none

Which of these equations describes a sodium current?

none of the above

which of the following neurotransmitters have glutamate as a precursor a. adrenaline b. dopamine c. serotonin d. noradrenaline e. acetylcholine f. none of the above

none of the above

event 5

synaptic vesicles move to the plasma membrane

the inactivation of the voltage-gated Na+ channels contributes to:

the absolute refractory period

what happens to the action potential if tthe voltage-gated Na+ channels are blocked by the selective inhibitor tetrodoxin(TTX)?

the action potential fails to occur

which of the following features of the action potential are correct?

the action potential travels from axon hillock to synaptic terminal b. the action pot. cant be evoked during the absolute refractory perios. c. the action potential is an "all or nothing" phenomenon

In neurons, voltage-gated Na+ channels are responsible for:

the depolarization phase of the action potential

which of the following statements baout the eq. potential is correct?

the eq. potential depends on both the charge and the valence of the iron

the velocity of tthe acion pottential alfong an axon is detetrmied by:

the presence of myelin sheath the diameter of the axon

the voltage-gated K+ channels are responsible for:

the repolarization phase of the action potential

which of the following stamements about the sodium-potassium pump are correct?

the sodium-potassium pump requires ATP to function b. the sodium potassium pump is an enzyme c. the sodium-potassiump pump pushes Na+ and K+ ions across the membrane against their concentration gradients d. th sodium-potassium pump exchanges internal Na+ for external K+ e. the sodium potassium pump is inserted into the plasma membrane

the lady-gaga-toxin is a toxin that disrupts the docking of synaptic vesivles in the presynaptic terminals of cholinergicneurons. what happens to synaptic transmission once the toxin is applied?

the synapse stops working because the cholinergic receptors on the postynaptic vesicles are blocked

in the nicotinic receptor of the neuromuscular junction, which subunits bind acetylcholine?

the α subunits

anterograde axonal transport

transport of molecules from the soma to the synaptic terminal

1 of the main differences btwn computed tomography and magnetic resonance imaging is that computed tomography utilizes X-rays whereas magnetic resonance utilizes a strong mag. field

true

G protein-coupled receptors consistt of a single polypeptide containing seven membrane-spanning alpha helices

true

Protein synthesis occurs in tthe ribosomes

true

The Nissl-staining technique allows one to visualized only the soma of a neuron

true

based on the example from class, the equilibrium potential for K+ ions is negative

true

each of the two connexons that constittute a gap junction is amde of 6 molecules of connexin

true

synaptic transmission is faster at synapses containng nicotinic receptors than muscarinic receptors

true

the eq. potential for a given ion species can be determined by using the nernst's equation

true

the physiological mechanisms underlying the generation of the action potential were leucidates using the giant axon in the nervous system of the squid

true

the plane of a section resulting from splitting a brain speciment into equal right and left halves is called midsagittal plane

true

event 2

voltage gated cA2+ channel open

which of these channels is responsible for the absolute refractory period?

voltage-gaetd Na+ channels

Retrogade axonal transport

Transport of molecules from the synaptic terminal to the soma

Phrenology was a discipline that attempted to correlate the srtucture of the head with personality traits

True

in a myelinated neuron, there is no myelin sheath at the level of the nodes of Ranvier

True

the resting membrane potential can be calculated using a mathematical formula called the Goldman equation

True

5-hydroxytryptamine in synthesized from:

Tryptophan

the precursor of dopamine is:

Tyrosine

which is the first event that occurs when an action potential arrives at the synaptic terminal?

Voltage-gate calcium channels open

which tyoes of ion channnels is called: "delayed rectifier"?

Voltage-gated K+ channel

which statement about axoplasmic trasport are correct?

a. anterograde axoplasmic transport does not require ATP b. anterograde axoplasmic transport is mediated by dyenin c. retrograde axoplasmic transport requires ATP d. retrograde axoplasmic transport is mediated by kinesin

if you are asked to engineer a biology-inspired voltafe gated Na+ channel, which of the following mechanisms will you include?

a. mechanism for channel inactivation b. a mechanism for ion selectivity c. mechanism for sensing changes in voltage d. a mechanism for channel opening.

which of the following features of the action potential are not correct? a. the action potential does not require the opening of voltage-gated ion channels b. the action potential travels drom the axon hillock to the synaptic terminal c. an ction potential consists of a depolarizing phase dollowed by a repolarizing phase d. the action potential does not require ATP to be generated e. the action potential cannot be evoked during the absolute refractory period. f. all of the above g. none of the above

a. the action potential does not require the opening of a voltage-gated ion channel

Which of these memrane receptors is an ionotropic receptor?

a.GABAa receptor b. glutamate receptor of AMPA type c. glutamate receptor of NMDA type d. Nicotinic receptor

Which is the first neurotransmitter that was discovered by scientist otto loewi

acetylcholine

which is the neurotransmitter of the neuromuscular junction

acetylcholine

which is the enzyme responsible for the degradation of acetylcholine?

acetylcholinesterase

Event 1

action potential arrives at the axon terminal

Which of the following costumes is mot likely to occur once ACh(acetylcholine) binds the nicotinic receptor of a neuron at rest?

an excitatory postsynaptic potential is generated in the postynaptic cell

the falling phase of the action potnetial is due to

an outward K+ current

event 6

docked synaptic vesicles fuse onto the pre-synaptic plasma membrane and release neurotransmitter

which of the following structures are meninges?

dura mater arachnoid membrane pia mater

which of the following statements about ion channels are correct?

each type of ion channel is selective to specific ions ion channels are expressed along the axon ion channels dont require ATP to function ion channelsare not exclusively present in neurons each ion channel is asociated with a specific conductance

serotonin is classified as a catecholamine

false

the depolarization phase of the action potential is due to an outward Na+ current

false

tyrosine is the precursor of serotonin

false

which of the following are characteristic of an electrical synapse?

ions and small molecules can pass from one cell to the other transmission in an electrical synapse is faster than in a chemical synapse the presynaptic and postsynaptic elements are connected by gap junctin made of connexons

All voltage-gatetd channels rapifly inactivatte after being opened

False

Tetrodotoxin(TTX) is a toxin that selectively blocks voltage-gated K+ channels

False

The repolarization phase of the action potential is due to an inward k+ current

False

what happens ot the action potential if the delayed-rectifier channes are blocked by a selective inhibitor called tetraethylammonium (TEA)?

A normal raising phase is followed by a much slower repolarization phase

which of the following channels or receptors are ligand-gated?

AMPA receptor Glycine receptor nicotinic receptor

which of the following is a G-protein coupled receptor?

Acetylcholine receptor of muscarinic type

the falling phase of the action potential is due to:

Exit of K+ ions out of the neuron through voltage -gated K+ channels

A synapse in which a presynaptic axon contacts the soma of a postsynaptic neuron is called

axosomatic

why the NMDA recepror is not functional at the restim membrane potential?

because Mg2+ ions block the recptor channel

how do you explain that in a standard neuron ENa is positive whereas EK is negative?

because Na+ and K+ are differently distributed across the plamsa membrane

which of these vents are characteristic of chem synaptic transmission?

binding of neurotransmitters to postsynaptic receptors activation of voltage gated Ca2+ channels in the presynaptic neuron recyle of the synapttic vesicles

Depolarization

change in a membrane potential from the value at resto to a less negative value

hyperpolarization

change in membrane potential from the value at rest to a more negative value

youre studying the synapse between neuron A and neuron B. stimulation of neuron A leads to the acrivation of neuron B but not vice versa. what is the type of synapse btween neuron A and neuron B?

chemical

Microtubule

contaclie element of the cytoskelon made of tubulin molecules

Microfilament

contractile element of the cytoskeleton made of actin molecules