Objective questions based on biology | Homework Help

1) The resting membrane potential in most neurons is determined by open channels that are permeable to which ion?

A. K+

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B. Cl-

C. Na+

D. Ca2+

E. Impermeable anions

2) At room temperature, the equilibrium potential of K+ in a cell with an internal concentration of K+ 10 fold higher than that of the external concentration will be approximately

A. -58 mV

B. -26 mV

C. 0 mV

D. +26 mV

E. +58 mV

3) Passive spread of voltage in axons can be increased by

A. Myelination

B. Increase in axon diameter

C. Decrease in membrane resistance

D. A and B

E. B and C

4) The maximum membrane potential in a mammalian neuron during an action potential (AP) is likely to be close to

A. +100 mV

B. The equilibrium potential of Na+

C. The equilibrium potential of K+

D. 0 mV

E. None of the above

5) Hodgkin and Huxley

A. Demonstrated the quantal nature of neuromuscular transmission.

B. Described the physiological properties of synaptic transmission.

C. Invented the patch clamp technique

D. Revealed the quantitative movements of ions across the membrane that leads to an action potential.

E. Studied the quantitative relation between ion movements and the post synaptic potential in a squid.

6) The picture below shows a typical current trace obtained from a voltage clamp recording of a neuron when the membrane potential is stepped from -65 mV to 0 mV.

…The currents labeled 12, 2, and 3 represent

A. 1. Capacitive current due to membrane charging 2. Current through voltage-gated Na+ channels. 3. Current through voltage-gated K+ channels

B. 1. Current through voltage-gated Na+ channels. 2. Current through voltage-gated K+ channels. 3. Capacitive current due to membrane charging.

C. 1. Current through voltage gated Na+ channels. 2. Current through Cl- channels. 3. Capacitive current due to membrane charging.

D. 1. Recording artifact current. 2. Capacitive current due to membrane charging 3. Current through voltage gated Na+ channels

E. 1. Capacitive current. 2 and 3 represent the same current through voltage gated Na+ channels

7) Golgi and Cajal shared the 1906 Nobel Prize for physiology and medicine. This was ironic because

A. Golgi developed the staining method used by Cajal to refute the reticular theory (that neurons were a continuous structure), which Golgi supported.

B. Cajal developed the staining method used by Golgi to refute the reticular theory, which Cajal supported.

C. The men had never met, even though they worked on the same topic, using the same animals.

D. The two men were friends even though at the time there was bitter rivalry between Italy and Spain, their home countries.

E. They were both ardent believers in homeopathy

8) Most inhibitory synapses are located on

A. Dendritic spines

B. Cell bodies

C. Dendritic shafts

D. A and B

E. B and C

9) The majority of excitatory ionotropic receptors responsible for excitatory neurotransmission in the CNS are activated by

A. GABA

B. Glycine

C. 5-HT

D. Acetylcholine

E. None of the above

10) What is the main inhibitory neurotransmitter in the brain?

A. GABA

B. Glycine

C. Histamine

D. Enkephalin

E. 5-HT

11) In a typical mammalian hippocampus at resting membrane potential, the following molecule(s) is/are bound to the NMDA receptor:

A. Glycine

B. GABA

C. Mg2+

D. Ca2+

E. A and C

12) At rest, neurons typically have an intracellular resting Ca2+ concentration of around

A. 1 M

B. 100 mM

C. 1 µM

D. 100 nM

E. 1 nM

13) The decision to fire an action potential is made at the axon initial segment. The reason for this is

A. It has a very low membrane resistance

B. It has a high density of voltage-gated Na+ channels

C. It is close to many excitatory synaptic inputs

D. It has a small diameter

E. All of the above

14) Which of the following statements are not true

A. Dendrites are capable of firing action potentials

B. To ensure that synapses have comparable strength at the axon initial segment, more glutamate receptors are often found in synapses more distal to the cell body.

C. Ca2+ transients can be localized to individual dendritic spines

D. Dendrites can grow in response to synaptic activity

E. No inhibitory synapses are found in the dendrites

15) The neuromuscular junction has been used a model for synaptic transmission because

A. It is an easily accessible preparation

B. Only one neurotransmitter is released

C. The end plate is the only region of the muscle fiber where neurotransmission occurs

D. Endplates are easily observable under a light microscope

E. All of the above

16) The chemical basis of neurotransmission was initially demonstrated by

A. Charles Sherrington

B. John Eccles

C. Otto Loewi

D. Bernard Katz

E. Henry Dale

17) Eserine prolongs the end plate potential by

A. Inhibiting choline transferase activity

B. Acting as a nicotinic acetylcholine receptor agonist

C. Blocking voltage-gated potassium channels

D. Inhibiting cholinesterase activity

E. A and B

18) The reversal potential of nicotinic acetylcholine receptors ion channel is close to zero in normal cells because

A. It is selectively permeable to chloride ions

B. It is permeable to both Na+ and K+

C. It is a metabotropic receptor

D. It is permeable to Ca2+ ions

E. It displays inward rectification

19) Blocking voltage gated Ca2+ channels in mammalian nerve terminals will

A. Increase spontaneous neurotransmitter release

B. Have no effect on neurotransmitter release

C. Block nerve terminal action potentials

D. Block action potential-evoked neurotransmitter release

E. A and D

20) Miniature end plate potentials

A. Represent release of single vesicles of neurotransmitter

B. Are blocked by tubocurarine

C. Can be mimicked by stimulating the motor neuron in the presence of a low extracellular Ca2+ concentrations

D. Occur spontaneously

E. All of the above

21) Synaptotagmin, a protein required for action-potential evoked neurotransmitter release

A. Has four binding sites for Ca2+

B. Is cleaved by botulinum toxin

C. Has relatively high affinity for Ca2+

D. Is responsible for spontaneous neurotransmitter release

E. None of the above

22) During chemical synaptic transmission, which of the following sequences of events occurs in a presynaptic neuron?

A. Depolarization of the terminal ? Ca2+ entry ?AP in axon ? vesicle fusion ? transmitter release.

B. AP in axon ? depolarization of the terminal ? Ca2+ entry ? vesicle fusion ? transmitter release.

C. Ca2+ entry ?AP in axon ? depolarization of the terminal ? vesicle fusion ? transmitter release.

D. AP in axon ? Ca2+ entry ? depolarization of the terminal ? vesicle fusion ? transmitter release.

E. Depolarization of the terminal ?AP in axon ?Ca2+ entry ? vesicle fusion ? transmitter release.

23) Metabotropic receptors

A. Underlie the majority of fast neurotransmission in the brain

B. Activate intracellular signaling pathways that undergo significant amplification

C. Directly couple to ion channels

D. Dimerize upon binding neurotransmitters

E. A and C

24) ?9-tetrahydracannabinol

A. Supresses appetite

B. Binds to on the same receptors as anandamide and 2-arachidonoylglycerol

C. Leads to adenylate cyclase activation

D. Is the drug menace which is destroying the youth of America in alarmingly increasing numbers

E. B and C

25) Endocannabinoid signaling

A. Can act on presynaptic nerve terminals by retrograde signaling

B. Can be induced by activation of postsynaptic Ca2+ channels

C. Can lead to long-term reduction of neurotransmitter release by phosphorylation of the proteins involved in neurotransmitter release

D. Can lead to short-term reduction of neurotransmitter release by inhibition of voltage-gated Ca2+ channels.

E. All of the above.

Section 2: Multiple choice questions (5 pts each)

26. Insulin stimulates glucose uptake in all of the following tissues EXCEPT:

a) liver

b) brain

c) skeletal muscle

d) white adipose

27. If an action potential is generated at the axon hillock of a neuron, all of the following are likely to have happened earlier, in this same neuron, EXCEPT:

a) spatial and/or temporal summation

b) conduction with decrement

c) graded potentials

d) all-or-none propagation

28. All of the following brain regions are part of the “Limbic System”, EXCEPT:

a) Locus coeruleus

b) Hippocampus

c) Amygdala

d) Prefrontal cortex

29. Long-term potentiation (LTP) is a mechanism that is heavily studied in the field of neuroscience and thought to underlie learning and memory. All of the following steps are involved in the process of LTP, EXCEPT:

a) NMDA receptor activation

b) Removal of a magnesium (Mg2+) blockade

c) Low frequency stimulation of the presynaptic neuron

d) AMPA receptor activation

30. Which of the following characteristics best accounts for the hypothalamus being the key brain region for control of homeostasis?

a) The hypothalamus is the only brain region that has both direct neural input and output to the peripheral nervous system

b) The hypothalamus has the greatest concentration of nuclei at which physiological set points are encoded, monitored, and controlled

c) The hypothalamus is the key brain region for the integration of neuroendocrine and autonomic function with emotion

d) The hypothalamus is essential for normal circadian timing

 

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