Engineering Questions with Answers - Multiple Choice Questions

MCQs on Cellular Membranes – Membrane Potential and Nerve Impulses

1 - Question

Response to external stimulus is called _______________
a) reaction
b) immunity
c) response
d) irritability

View Answer

Answer: d
Explanation: All organisms respond to external stimulus, a property known as irritability. Even the smallest amoeba and bacterial cell possess this feature. In response to external stimulus, a cell may activate from its whole range of metabolic pathways.




2 - Question

Information is coded in the form of fast moving impulse in which types of cells?
a) epithelial
b) endothelial
c) neurons
d) hepatocytes

View Answer

Answer: c
Explanation: Nerve cells are called neurons; they conduct, transmit and collect information in form of electrical impulses. The structure of neurons is unique and different from other cells in the body.




3 - Question

Which part of a neuron receives information from other neurons?
a) cell body
b) axon
c) dendrites
d) myelin sheath

View Answer

Answer: c
Explanation: The fine extensions from cell body of the neurons are called dendrites which receive information from external sources, usually other neighboring neurons.




4 - Question

The information is forwarded from the neuron through which part?
a) axon
b) soma
c) dendrites
d) nucleus

View Answer

Answer: a
Explanation: Axon is a single prominent extension that emerges from the cell body and is responsible for conducting outgoing impulses away from the cell and towards other cells.




5 - Question

Myelin sheath is composed mainly of _____________
a) proteins
b) lipids
c) nucleic acids
d) cholesterol

View Answer

Answer: b
Explanation: Myelin sheath surrounds the axon which extends from the soma of a neuron. Myelin sheath is composed mainly of lipids and their function is to prevent loss of impulses.




6 - Question

Membrane potential is present only in nerve cells.
a) True
b) False

View Answer

Answer: b
Explanation: A membrane potential of -70 mV is present in neurons. However this phenomena is not specific to neurons, membrane potential exists in other types of cells as well from anywhere between -15 to -100 mV.




7 - Question

. Which of the following exists in nerve and muscle cells?
a) resting potential
b) membrane potential
c) potassium equilibrium potential
d) sodium equilibrium potential

View Answer

Answer: a
Explanation: Nerve and muscle cells are the only excitable cells in the body; the potential difference that exists between extracellular and intracellular environments is termed as resting potential. However in other cells this voltage is termed as membrane potential.




8 - Question

Which of the following has the highest permeability in a resting nerve cell?
a) Na+
b) Cl–
c) I–
d) K+

View Answer

Answer: d
Explanation: K+ has the highest permeability in resting nerve cells. Most of the ion channels open in the membrane of a resting nerve cell are selective for potassium, referred to as potassium leak channels.




9 - Question

On which of the following organisms, the research on nerve cells was first carried out?
a) Drosophila melanogaster
b) Grasshopper
c) Giant squid
d) Octopus

View Answer

Answer: c
Explanation: The first research on action potential and nerve impulses was carried on the axons of giant squid in the late 1940s and early 1950s by Alan Hodgkin, Andrew Huxley, and Bernard Katz.




10 - Question

Depolarization is when ___________ ions flow inside the neuron’s membrane.
a) Potassium
b) Sodium
c) Chloride
d) Magnesium

View Answer

Answer: b
Explanation: Depolarization is the flow of sodium ions into the membrane. These are positively charged and reduce the polarity of a cell with respect to external environment and are therefore cause depolarization.




11 - Question

A neuron fires when _____________________
a) action potential is achieved
b) apoptosis is induced
c) re-stimulation occurs
d) stimulation ceases

View Answer

Answer: a
Explanation: When the external stimulation is strong enough to reach the threshold value which is around -50 mV, the action potential is generated, and firing of the neurons occurs. This is actually the response to stimulus.




12 - Question

Saltatory conduction occurs due to _______________
a) axon hillock
b) soma
c) myelin sheath
d) nodes of ranvier

View Answer

Answer: c
Explanation: Saltatory conduction occurs due to the presence of lipid-rich myelin sheath on the length of the axon. Due to this the action potential jumps from one node to the other, resulting in faster action potential transmission.




13 - Question

The parts in the figure are a)__________, b)_____________, c)___________, d)____________.
a) dendrites, soma, myelin sheath, nodes of ranvier
b) dendrites, soma, cell body, axon hillock, myelin sheath
c) soma, axon hillock, myelin sheath, dendrites
d) soma, axon hillock, axon, dendrites

View Answer

Answer: a
Explanation: Dendrites are the fine extensions from cell body, responsible for receiving information from other neurons. The information is processed in soma and then travels down the length of the axon where myelin sheath is discontinuously present. The gaps between the sheath are called nodes of Ranvier.




14 - Question

Local anesthetics act by _____________ the ion channels.
a) inactivating
b) opening
c) closing
d) mutating

View Answer

Answer: c
Explanation: Local anesthetics act by closing the ions channels present in the membranes of sensory cells and neurons. As a result no action potential is generated and information can not be sent to the brain about events occurring at the skin or teeth.




15 - Question

Action potential can only flow in the forward direction.
a) True
b) False

View Answer

Answer: a
Explanation: Action potential can only move in the forward direction generating nerve impulses. This is because the area of the membrane that has just experienced action potential, remains in a refractory period and can not be stimulated again.

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