BIOL371 MODULE 2 EXAM QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTIONS GRADED A++ LATEST
UPDATE
Active Transporter (protein)
A transmembrane protein that can move ions or other molecules across the membrane
against their concentration/electrochemical gradients. If an active transporter is called a
'pump', this indicates that the transporter itself hydroylzes ATP to provide the chemical
energy needs to oppose the diffusive force acting on the transported molecule. Active
transporters typically move only 1 or a few (2-3) molecules per ATP hydrolysis cycle,
meaning they act relatively slowly (100000s of molecules per second).
Current (I)
A flow of charge (i.e. charged particles) from one location to another, measured by the
unit the Ampere (1 coulomb per second)
Depolarization
A change in membrane potential where Vm becomes less negative (or more positive)
than RMP.
Diffusive Force (Df)
The force on particles that is generated by concentration gradients (which according to
Brownian motion causes particles to move from an area of high concentration to an
area of lower concentration)
,Electromotive Force (EMF)
The force experienced by charged particles in an environment with a voltage gradient,
which would cause the charged particles to move from one location to another.
Excitable
Excitable cells are able to rapidly alter their transmembrane potential (Vm), encoding
information by voltage changes from the resting Vm. These changes occur over the
time scale of milliseconds.
Hyperpolarization
A change in membrane potential where Vm becomes more negative than RMP.
Ion Channel
A transmembrane protein that creates a pore or hole between one side of the
membrane and the others, allowing specific ions to travel rapidly and in large numbers
(millions to billions per second) from one side to the other.
Ion Valence
The total charge on an individual ion species.
Permeability
The ability of a given molecule to cross a membrane.
Potential
A 'potential' is a specific change in the membrane potential of an excitable cell, which
makes it deviate away from RMP for a brief period of time (typically on the order of
milliseconds to tens of milliseconds).
- typically grouped as AP or graded potential
Post-synaptic Potential (PSP)
, An electrical signal in neuronal (or muscle) cell membranes which is induced when a
neurotransmitter activates receptors at the (post-synaptic side of the) synapse. PSPs
can be excitatory or inhibitory, and can vary in their amplitude and duration, though they
are almost always smaller in amplitude and longer in duration than APs.
- ex stretch receptor, interneuron, etc.
Repolarization
A change in membrane potential where Vm returns toward RMP.
Resting Membrane Potential (RMP)
The transmembrane potential of an excitable cell when it is 'at rest' -i.e. when no
stimulus (sensory or synaptic) has occurred.
- -60mV to -80mV in most organisms
Resistance (R)
Measures how difficult (energy-intensive) it is for current (I) to flow from one location to
another.
- Measured by the unit Ohm
(Trans)membrane Potential (Vm)
A voltage difference across the cell membrane that can be measured using a pair of
electrodes (one inside the cell and one outside).
- usually -60mV to -90mV
Voltage (V)
The difference in electrical potential between two points. It corresponds to the amount of
work (energy) that needs to be done to move a charge between those points. Voltage
differences can act as a force, providing the energy for currents to flow, or can be built
WITH COMPLETE SOLUTIONS GRADED A++ LATEST
UPDATE
Active Transporter (protein)
A transmembrane protein that can move ions or other molecules across the membrane
against their concentration/electrochemical gradients. If an active transporter is called a
'pump', this indicates that the transporter itself hydroylzes ATP to provide the chemical
energy needs to oppose the diffusive force acting on the transported molecule. Active
transporters typically move only 1 or a few (2-3) molecules per ATP hydrolysis cycle,
meaning they act relatively slowly (100000s of molecules per second).
Current (I)
A flow of charge (i.e. charged particles) from one location to another, measured by the
unit the Ampere (1 coulomb per second)
Depolarization
A change in membrane potential where Vm becomes less negative (or more positive)
than RMP.
Diffusive Force (Df)
The force on particles that is generated by concentration gradients (which according to
Brownian motion causes particles to move from an area of high concentration to an
area of lower concentration)
,Electromotive Force (EMF)
The force experienced by charged particles in an environment with a voltage gradient,
which would cause the charged particles to move from one location to another.
Excitable
Excitable cells are able to rapidly alter their transmembrane potential (Vm), encoding
information by voltage changes from the resting Vm. These changes occur over the
time scale of milliseconds.
Hyperpolarization
A change in membrane potential where Vm becomes more negative than RMP.
Ion Channel
A transmembrane protein that creates a pore or hole between one side of the
membrane and the others, allowing specific ions to travel rapidly and in large numbers
(millions to billions per second) from one side to the other.
Ion Valence
The total charge on an individual ion species.
Permeability
The ability of a given molecule to cross a membrane.
Potential
A 'potential' is a specific change in the membrane potential of an excitable cell, which
makes it deviate away from RMP for a brief period of time (typically on the order of
milliseconds to tens of milliseconds).
- typically grouped as AP or graded potential
Post-synaptic Potential (PSP)
, An electrical signal in neuronal (or muscle) cell membranes which is induced when a
neurotransmitter activates receptors at the (post-synaptic side of the) synapse. PSPs
can be excitatory or inhibitory, and can vary in their amplitude and duration, though they
are almost always smaller in amplitude and longer in duration than APs.
- ex stretch receptor, interneuron, etc.
Repolarization
A change in membrane potential where Vm returns toward RMP.
Resting Membrane Potential (RMP)
The transmembrane potential of an excitable cell when it is 'at rest' -i.e. when no
stimulus (sensory or synaptic) has occurred.
- -60mV to -80mV in most organisms
Resistance (R)
Measures how difficult (energy-intensive) it is for current (I) to flow from one location to
another.
- Measured by the unit Ohm
(Trans)membrane Potential (Vm)
A voltage difference across the cell membrane that can be measured using a pair of
electrodes (one inside the cell and one outside).
- usually -60mV to -90mV
Voltage (V)
The difference in electrical potential between two points. It corresponds to the amount of
work (energy) that needs to be done to move a charge between those points. Voltage
differences can act as a force, providing the energy for currents to flow, or can be built
