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2. (20 pts) A 20 um diameter cell at rest has a potential of -60 mV...
(a) Find the capacitance of the cell membrane. (b) Suppose the potential difference across the cell...
(a) Find the capacitance of the cell membrane.
(b) Suppose the potential difference across the cell wall is
92 mV. Find the magnitude of the charge stored on either side of
the cell wall.
hboard> My courses > Spring Semester 2019 SP2019-PHYS-142-001 Topic 3 HW CH18.2 Capacitance due 1/22 Question 3 Partially correct 0.33 points out of 1.00 The fuids Inside and outside a cell are good conductors separated by the cell wall, which is a dielectric. Thus the cell...
Consider a motor neuron: Diameter = 100 um Permittivity of vacuum = 8.85 x 10-12 Farad/m...
Consider a motor neuron: Diameter = 100 um Permittivity of vacuum = 8.85 x 10-12 Farad/m Dielectric constant of plasma membrane = 8 Faraday's constant = 96,500 coulombs/mol Cell osmolarity = 290 mOsM; estimate 50% are positive ions What percentage of the positive ions within a cell need to cross the membrane to create a -80 mV Em? Hints: Find how much charge is needed to generate Em using Q=C*V (as discussed in class). Convert the charge (coulombs) to moles...
A spherical neuron, 10 um in diameter, when hyperpolarized falls 50% of the voltage from rest...
A spherical neuron, 10 um in diameter, when hyperpolarized falls 50% of the voltage from rest to of its steady-state voltage in 2 seconds. It has an Rm of 4.5 x 10-6 olhms cm2. When it is depolarized by 30 mV, how many net positive ions enter the cell? . Hint: consider how the membrane capacitor is charged.
The membrane that surrounds a certain type of living cell has a surface area of 4.2...
The membrane that surrounds a certain type of living cell has a surface area of 4.2 x 10-9 m2 and a thickness of 1.3 x 10-8 m. Assume that the membrane behaves like a parallel plate capacitor and has a dielectric constant of 5.0. (a) The potential on the outer surface of the membrane is +78.7 mV greater than that on the inside surface. How much charge resides on the outer surface? (b) If the charge in part (a) is...
The electric potential inside a cell is negative with respect to the surrounding extracellular fluid. The...
The electric potential inside a cell is negative with respect to the surrounding extracellular fluid. The potential difference across the cell membrane is 70 mV. If a sodium ion with a mass of 22.98 u and a charge of 1.6 X 10-19 C is accelerated from rest through a membrane channel (proteins which allow the passive movement of ions (ion channels), water (aquaporins) or other solutes to passively pass through the membrane down their electrochemical gradient). Find the speed of...
th charge g, are at different and with one diagonal of length a and the 10....
th charge g, are at different and with one diagonal of length a and the 10. As shown in the figure below, three particles, each wi cormers of a rhombus with sides of length a other of length b. (6 pts.) 4y 91 42 What is the electric potential energy of the charge distribution? c. E- 12ka/a 11. Under certain circumstances, potassium ions K' move across the 8 nm thick cell membrane from the inside to the outside. The potential...
The axon has a diameter of 30 um, a length of 5 cm. I calculated the...
The axon has a diameter of 30 um, a length of 5 cm. I calculated
the capacitance to be 12.525. The fractional change in the
concentration of Na+ ions inside the axon during one
action potential is 2.7 x 10-5 .
The energy used to create one action potential along this axon is pJ. (Hint: The energy to transmit one pulse is equivalent to the energy stored by charging the axon capacitance.) The minimum power that would be required for...
1. The headlights on an automobile are 125 cm apart. At what distance will the lights appear to b...
1. The headlights on an automobile are 125 cm apart. At what distance will the lights appear to be just resolvable to a person whose nocturnal pupils are 4.5 mm in 2. Assume the range of pupil variation during adaptation of a normal eye is from 2.0 to 7.1 mm. What is the corresponding range of distances over which it can detect 3. Two stars make an angle of 1 x 10-3 radians at the eye of an observer. A...
Active (uM) Cell count (% of control) DNA content (% of control) DNA fragmentation (% of...
Active (uM) Cell count (% of control) DNA content (% of control) DNA fragmentation (% of control) Caspase-3 activity (% of control) 0 100 100 100 100 1 80 80 200 200 10 50 50 350 350 100 20 20 500 500 Create a table and a graph for the effect of the active on DNA fragmentation, give a title that includes whether the active is beneficial or harmful for cancer management/treatment (use Table’s column 4/DNA fragmentation info) Create a...
(a) Find the capacitance of the cell membrane.
(b) Suppose the potential difference across the cell wall is
92 mV. Find the magnitude of the charge stored on either side of
the cell wall.
hboard> My courses > Spring Semester 2019 SP2019-PHYS-142-001 Topic 3 HW CH18.2 Capacitance due 1/22 Question 3 Partially correct 0.33 points out of 1.00 The fuids Inside and outside a cell are good conductors separated by the cell wall, which is a dielectric. Thus the cell...
Consider a motor neuron: Diameter = 100 um Permittivity of vacuum = 8.85 x 10-12 Farad/m Dielectric constant of plasma membrane = 8 Faraday's constant = 96,500 coulombs/mol Cell osmolarity = 290 mOsM; estimate 50% are positive ions What percentage of the positive ions within a cell need to cross the membrane to create a -80 mV Em? Hints: Find how much charge is needed to generate Em using Q=C*V (as discussed in class). Convert the charge (coulombs) to moles...
th charge g, are at different and with one diagonal of length a and the 10. As shown in the figure below, three particles, each wi cormers of a rhombus with sides of length a other of length b. (6 pts.) 4y 91 42 What is the electric potential energy of the charge distribution? c. E- 12ka/a 11. Under certain circumstances, potassium ions K' move across the 8 nm thick cell membrane from the inside to the outside. The potential...
The axon has a diameter of 30 um, a length of 5 cm. I calculated
the capacitance to be 12.525. The fractional change in the
concentration of Na+ ions inside the axon during one
action potential is 2.7 x 10-5 .
The energy used to create one action potential along this axon is pJ. (Hint: The energy to transmit one pulse is equivalent to the energy stored by charging the axon capacitance.) The minimum power that would be required for...
1. The headlights on an automobile are 125 cm apart. At what distance will the lights appear to be just resolvable to a person whose nocturnal pupils are 4.5 mm in 2. Assume the range of pupil variation during adaptation of a normal eye is from 2.0 to 7.1 mm. What is the corresponding range of distances over which it can detect 3. Two stars make an angle of 1 x 10-3 radians at the eye of an observer. A...
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