Bio E109 Module 1 Questions With Complete Solutions
Articulate the key distinctions between the absolute and relative
refractory periods. Correct Answers absolute- (Between zero
and 2MS) it is impossible during this period for a second action
potential from a stimulus to occur. early in the absolute
refractory period, large proportions of channels are opened and
the membrane is ready to go with the whole bunch of sodium
channels that want to depolarize and open the activation gates.
late in the absolute refractory period is when the cell begins to
repolarize and a large proportion of channels are being closed
relative- (2 to 4MS)Early in the relative refractory period is
when the large proportions of channels are swinging closed and
the inactivation gates are being opened. late in the relative
refractory period is when there is a larger proportion of channels
that have been reset
Contrast how spatial summation from an excitatory synapses
and inhibitory synapse differs from the summation from two
excitatory synapses. Correct Answers when there are two
excitatory synapses, they both allow an influx of sodium that
diffuses to interior of the cell. Later down on the axon Hillock,
the summation will cause a greater depolarization that is above
the threshold leading to an action potential. this only works if
the summation of both is above the threshold, if they are below
the threshold, then there will be no action potential
The summation of an excitatory synapse and an inhibitory
synapse will cancel out any reaction and inhibit an action
potential from being created because it's below the threshold.
The hyper polarization of the inhibitory synapse can block the
ability of the excitatory synapse to create an action potential in
the axon
,Contrast the differences between the membrane potential and the
equilibrium potential. Correct Answers The member potential
is the voltage across the cellular membrane
The equilibrium potential is the membrane potential if only one
ion mattered so for only one ion type
Contrast the major differences between the voltage-gated
channels for K+ and Na+. Correct Answers The sodium
channels occur first, they are faster than the potassium channels.
Sodium channels are used to depolarize the action potential. The
potassium channels are used to repolarize the action potential.
Sodium channels have an inactivation gate while the potassium
channels do not have an inactivation gate. The inactivation gate
for sodium channels stop the permeability of sodium into the
cell, while the potassium channel simply closes the activation
gate to stop permeability of potassium out of the cell
Contrast the major differences in functional properties between
the two types of transmembrane proteins that permit ion flux
across a cellular membrane. Correct Answers 1. carrier protein-
primary active transport uses ATP to move Na+ and K+ against
the chemical gradients
2. channel protein- leaky potassium pores (leak channel) that is
manipulated through facilitated diffusion does that not require
energy
Contrast the primary differences between inhibitory and
excitatory chemical synapses. Correct Answers excitatory
synapses (involve sodium) depolarize by ligand gated channels
that increase the permeability of sodium.
, inhibitory synapses are in different sides of the postsynaptic cell.
The hyper polarization is triggered through the ligand gated
channels that increase the permeability of chloride. Chloride
ions will be permitted to move across the membrane when they
bind onto a neurotransmitter. Chloride has a very l
electronegative potential because of it's negative valence
electrons and when the permeability is high for chloride, it tends
to hyperpolarized the membrane
Contrast the properties of a membrane that the Goldman
equation considers that the Nernst equation does not. Correct
Answers considers the permeability of the membrane for that
particular ion as well as all the ions that matter such as
potassium sodium and chloride
The equation equates how permeability dictates how close the
membrane potential is to the equilibrium potential of an ion
Define "homeostasis" and explain its relevance in physiology.
Correct Answers A constant internal state against changes in
environment and activity. Since we are constantly changing our
physiology, homeostasis becomes challenge and the organ
system stabilize internal environments
Define the 4 types of tissue in the body. Correct Answers
connective, epithelia, nervous, and muscle
Define the principle that models the rate of diffusion across a
membrane. Correct Answers fick's law: rate of diffusion is
proportional to the concentration difference x the permeability x
the area all over the thickness of the membrane
Articulate the key distinctions between the absolute and relative
refractory periods. Correct Answers absolute- (Between zero
and 2MS) it is impossible during this period for a second action
potential from a stimulus to occur. early in the absolute
refractory period, large proportions of channels are opened and
the membrane is ready to go with the whole bunch of sodium
channels that want to depolarize and open the activation gates.
late in the absolute refractory period is when the cell begins to
repolarize and a large proportion of channels are being closed
relative- (2 to 4MS)Early in the relative refractory period is
when the large proportions of channels are swinging closed and
the inactivation gates are being opened. late in the relative
refractory period is when there is a larger proportion of channels
that have been reset
Contrast how spatial summation from an excitatory synapses
and inhibitory synapse differs from the summation from two
excitatory synapses. Correct Answers when there are two
excitatory synapses, they both allow an influx of sodium that
diffuses to interior of the cell. Later down on the axon Hillock,
the summation will cause a greater depolarization that is above
the threshold leading to an action potential. this only works if
the summation of both is above the threshold, if they are below
the threshold, then there will be no action potential
The summation of an excitatory synapse and an inhibitory
synapse will cancel out any reaction and inhibit an action
potential from being created because it's below the threshold.
The hyper polarization of the inhibitory synapse can block the
ability of the excitatory synapse to create an action potential in
the axon
,Contrast the differences between the membrane potential and the
equilibrium potential. Correct Answers The member potential
is the voltage across the cellular membrane
The equilibrium potential is the membrane potential if only one
ion mattered so for only one ion type
Contrast the major differences between the voltage-gated
channels for K+ and Na+. Correct Answers The sodium
channels occur first, they are faster than the potassium channels.
Sodium channels are used to depolarize the action potential. The
potassium channels are used to repolarize the action potential.
Sodium channels have an inactivation gate while the potassium
channels do not have an inactivation gate. The inactivation gate
for sodium channels stop the permeability of sodium into the
cell, while the potassium channel simply closes the activation
gate to stop permeability of potassium out of the cell
Contrast the major differences in functional properties between
the two types of transmembrane proteins that permit ion flux
across a cellular membrane. Correct Answers 1. carrier protein-
primary active transport uses ATP to move Na+ and K+ against
the chemical gradients
2. channel protein- leaky potassium pores (leak channel) that is
manipulated through facilitated diffusion does that not require
energy
Contrast the primary differences between inhibitory and
excitatory chemical synapses. Correct Answers excitatory
synapses (involve sodium) depolarize by ligand gated channels
that increase the permeability of sodium.
, inhibitory synapses are in different sides of the postsynaptic cell.
The hyper polarization is triggered through the ligand gated
channels that increase the permeability of chloride. Chloride
ions will be permitted to move across the membrane when they
bind onto a neurotransmitter. Chloride has a very l
electronegative potential because of it's negative valence
electrons and when the permeability is high for chloride, it tends
to hyperpolarized the membrane
Contrast the properties of a membrane that the Goldman
equation considers that the Nernst equation does not. Correct
Answers considers the permeability of the membrane for that
particular ion as well as all the ions that matter such as
potassium sodium and chloride
The equation equates how permeability dictates how close the
membrane potential is to the equilibrium potential of an ion
Define "homeostasis" and explain its relevance in physiology.
Correct Answers A constant internal state against changes in
environment and activity. Since we are constantly changing our
physiology, homeostasis becomes challenge and the organ
system stabilize internal environments
Define the 4 types of tissue in the body. Correct Answers
connective, epithelia, nervous, and muscle
Define the principle that models the rate of diffusion across a
membrane. Correct Answers fick's law: rate of diffusion is
proportional to the concentration difference x the permeability x
the area all over the thickness of the membrane
