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.
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A spherical neuron, 10 um in diameter, when hyperpolarized falls
50% of the voltage from rest...
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...
2. (20 pts) A 20 um diameter cell at rest has a potential of -60 mV...
2. (20 pts) A 20 um diameter cell at rest has a potential of -60 mV across its membrane. The cell membrane has a capacitance of 1 uF/cm². Charge of an electron = -1.6 x 10-*°C. a) How many potassium ions in the cell are needed to charge the membrane? i. 320 ii. 1.6 x 10 iii. 4.7 x 10 iv. 9.1 x 1011 b) How much energy is stored in the cell membrane?! i. 1.2 x 10-16 ii. 2.3...
9. Voltage clamps are normally used to “clamp” or “freeze” membrane potential at a particular value...
9. Voltage clamps are normally used to “clamp” or “freeze”
membrane potential at a particular value and then measure the
resulting ionic currents. Explain how setting a voltage clamp at
the presynaptic terminal to a very positive potential can prevent
synaptic transmission (hint: synaptic transmission is triggered
using voltage-gated Ca++ channels, and you can assume typical Ca
concentrations inside and outside the cell from the table.
Please explain how setting a voltage clamp at the presynaptic
terminal to a very...
Lo 10: Electrochemical Gradient The difference in voltage across the membrane is called the __________________________________. The...
Lo 10: Electrochemical Gradient The difference in voltage across the membrane is called the __________________________________. The inside of a normal cell is ___________________ (+/-); while the outside is ___________(+/-). The resting membrane potential of a neuron is ___________mV. Diagram the relative ratios of Ca++, Na+ and K+ in a cell under resting conditions. Draw an arrow for each of the molecules indicating which direction would be passive transport (into or out of the cell). For each of the following sentences, fill in...
Question 9 10 pts _cells show electromotility, they increase or decrease in length when the voltage...
Question 9 10 pts _cells show electromotility, they increase or decrease in length when the voltage of the cell changes. Outer hair Inner hair Auditory Nerve Primary auditory cortex Question 8 10 pts True/False The bones in the middle ear amplify sound energy. True False Question 5 10 pts When auditory nerve fibers show phase-locking of their action potentials to a location on a periodic soundwave it is called: Hint: "Phase locking" could occur at a peak, trough, or somewhere...
An axon is a long, slender projection of a nerve cell, or neuron e , that...
An axon is a long, slender projection of a nerve cell, or neuron e , that typically conducts electrical impulses e away from the neuron's cell body e . Capacitance (C) is the ability of a system to store an electric charge. In this activity, you'll use information given about these fascinating structures to calculate the capacitance of an axon. Αxon Axon terminal Dendrite Node of Ranvier Soma Axon Schwann cell Myelin sheath Nucleus plasma membrane cytoplasm, a conducting liquid...
4. Inspired by the natural design of cell membranes, you have invented a strange new semi-permeable...
4. Inspired by the natural design of cell membranes, you have invented a strange new semi-permeable membrane consisting of a water-impemeable base layer interspersed with hydrophilic transmembrane glycoproteins which form three types of channels. Channel type 'A' is approx imately 3 angstroms in diameter and lined with negative charges Channel type 'B' is approximately 3 angstroms in diameter also but lined with positive charges Channel type C is approximately 4 angstroms in diameter and electrically neutral This membrane separates two...
11) For the circuit shown, R1= R3 = R9 = R11= 102.0 Ohms, the rest of...
11)
For the circuit shown, R1= R3 =
R9 = R11= 102.0 Ohms, the rest of the
resistors are 204.0 Ohms.
a) Without doing any simplification (or combination) identify
the number of pairs of resistors (that is 2 resistors) that are in
series.
b) Without doing any simplification (or combination) identify
the number of pairs of resistors (that is 2 resistors) that are in
parallel.
c) Find R12 the equivalent resistance of resistors
R1, and R2.
d) Find R123 the...
Sorry for posting more than one question -- someone said they needed the rest of the...
Sorry for posting more than one question -- someone said they
needed the rest of the questions to better understand how to answer
one!
Question 1 1 pts Using the data provided in the table below for an "average" axon, we found in the previous lab and in the pre-lab questions for this lab) that the membrane resistance and membrane capacitance were about 44M0 = 44 x 102 and 60pF = 60 x 10-12 F, respectively, for a membrane segment...
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...
2. (20 pts) A 20 um diameter cell at rest has a potential of -60 mV across its membrane. The cell membrane has a capacitance of 1 uF/cm². Charge of an electron = -1.6 x 10-*°C. a) How many potassium ions in the cell are needed to charge the membrane? i. 320 ii. 1.6 x 10 iii. 4.7 x 10 iv. 9.1 x 1011 b) How much energy is stored in the cell membrane?! i. 1.2 x 10-16 ii. 2.3...
9. Voltage clamps are normally used to “clamp” or “freeze”
membrane potential at a particular value and then measure the
resulting ionic currents. Explain how setting a voltage clamp at
the presynaptic terminal to a very positive potential can prevent
synaptic transmission (hint: synaptic transmission is triggered
using voltage-gated Ca++ channels, and you can assume typical Ca
concentrations inside and outside the cell from the table.
Please explain how setting a voltage clamp at the presynaptic
terminal to a very...
Question 9 10 pts _cells show electromotility, they increase or decrease in length when the voltage of the cell changes. Outer hair Inner hair Auditory Nerve Primary auditory cortex Question 8 10 pts True/False The bones in the middle ear amplify sound energy. True False Question 5 10 pts When auditory nerve fibers show phase-locking of their action potentials to a location on a periodic soundwave it is called: Hint: "Phase locking" could occur at a peak, trough, or somewhere...
An axon is a long, slender projection of a nerve cell, or neuron e , that typically conducts electrical impulses e away from the neuron's cell body e . Capacitance (C) is the ability of a system to store an electric charge. In this activity, you'll use information given about these fascinating structures to calculate the capacitance of an axon. Αxon Axon terminal Dendrite Node of Ranvier Soma Axon Schwann cell Myelin sheath Nucleus plasma membrane cytoplasm, a conducting liquid...
4. Inspired by the natural design of cell membranes, you have invented a strange new semi-permeable membrane consisting of a water-impemeable base layer interspersed with hydrophilic transmembrane glycoproteins which form three types of channels. Channel type 'A' is approx imately 3 angstroms in diameter and lined with negative charges Channel type 'B' is approximately 3 angstroms in diameter also but lined with positive charges Channel type C is approximately 4 angstroms in diameter and electrically neutral This membrane separates two...
Sorry for posting more than one question -- someone said they
needed the rest of the questions to better understand how to answer
one!
Question 1 1 pts Using the data provided in the table below for an "average" axon, we found in the previous lab and in the pre-lab questions for this lab) that the membrane resistance and membrane capacitance were about 44M0 = 44 x 102 and 60pF = 60 x 10-12 F, respectively, for a membrane segment...
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