A B C
(a) Vm PK PNa
(b) PNa Vm PK
(c) PK Vm PNa
(d) Vm PNa PK
- Which of the following is not true about
depolarizing phase of action potential
(a) Depolarisation occurs due to rapid influx
of Na+.
(b) The polarity of the membrane at the site
of depolarisation is reversed.
(c) The outer surface of the membrane
becomes negatively charged.
(d) The membrane is more permeable to K+
and nearly impermeable to Na+. - Study the following events that occur during
the generation of an action potential.
(1) Hyperpolarization (2) Stimulation
(3) Repolarization (4) Depolarization
What is the correct sequence of these events?
(a) (3), (4), (2), (1) (b) (2), (3), (4), (1)
(c) (2), (4), (3), (1) (d) (2), (1), (4), (3) - During an action potential, repolarization of
the axonal membrane is due to
(a) Influx Na+ (b) Influx of K+
(c) Efflux of Na+ (d) Efflux of K+ - Each of the following is an integral part of
neuron except
(a) Nissl’s granule (b) Dendrite
(c) Nucleus (d) Myelin sheath - Which of the following is true about an action
potential?
(a) The membrane to first hyperpolarizes
and then depolarizes
(b) It is triggered when depolarization
reaches the threshold
(c) Its amplitude varies depending on the
strength of the stimulus
(d) Action potentials are generated in the
dendrites and cytons - The ion channels in the axonal membrane are
analogous to
(a) Capacitors (b) Resistors
(c) Batteries (d) Insulators - The movement of Na+ and K+ into and out
of the axoplasm through channels during an
action potential occurs by
(a) Simple diffusion
(b) Facilitated diffusion
(c) Primary active transport
(d) Secondary active transport
Q.Nos.(16-20)Study the following diagram
depicting an action potential in a neuron and
answer the questions that follow.- The change in membrane potential between
‘B’ and ‘D’ is primarily due to
(a) Influx of K+ (b) Efflux of K+
(c) Influx Na+ (d) Efflux of Na+ - The membrane potential is closest to K+
equilibrium potential at which point?
(a) A (b) G (c) D (d) F - What happens at the point ‘D’?
(a) Voltage-gated Na+ channels are
inactivated and voltage-gated K+
channels are activated
(b) Voltage-gated Na+ channels are activated
and voltage-gated K+ channels are
inactivated
(c) Voltage-gated Na+ channels and voltage-
gated K+ channels are activated
(d) Voltage-gated Na+ channels and voltage-
gated K+ channels are inactivated - Relative refractory period is represented by
(a) DF (b) BD (c) FH (d) BF - Threshold potential is represented by the
point
(a) A (b) B (c) D (d) G - c 2. a 3. b 4. a 5. d
- c 7. b 8. d 9. d 10. c
- d 12. d 13. b 14. b 15.a
- c 17. b 18. a 19. c 20. b