Q1. The table below shows the current recorded from patch clamp experiments on potassium channels in cultured rabbit lacrimal gland cells at different stimulating membrane potentials.Current (pA)Membrane potentials (mV)1.9600.95500.0540-0.930-1.8520-2.810-3.80-4.8-10-5.7-20-6.65-30-7.6-40-8.6-50 Draw an I – V curve. (8 marks)Calculate the reversal potential. (2 marks)Calculate the conductance of this ion channel. (6 marks) Q2. A human red blood cell has a membrane surface area of about 81µm2 and a membrane thickness of about 110 Aº. If the concentration of urea in the extracellular fluid is 1.6mM, and its intracellular concentration is 0.8mM, calculate the flux of urea in µmoles/sec across the red blood cell membrane. Assume that the diffusion coefficient of urea is 1 x 10-8 cm2/sec. (10 marks) Q3. During the course of a neurosurgical procedure a drug is applied to the surface of the brain in order to inhibit the activity of a group of neurons that lie 3mm below the surface. Approximately how long will it take the drug to diffuse from the surface to those neurons? Assume the diffusion coefficient of the drug in brain tissue is 3 x 10-4 cm2/sec. (6 marks) Q4. Calculate the membrane potential (Vm) of a cell, given the following resistances and equilibrium potentials. Need to show all calculations. (12 marks)EK = – 94mV, RK = 0.5 x 106 Ω, ENa = 66mV, RNa = 0.5 x 106 Ω Q5. If EK = -92 mV and VM = -72 mV what will be the direction and magnitude of the ECDF? (4 marks) Q6. If ENa = 66 mV and VM = -52 mV what will be the direction and magnitude of the ECDF? (4 marks) Q7. Draw an I-V plot for two different non-voltage dependent ionic currents IA and IB under the following conditions:· When the conductance (g) is the same (2pS) for both ions A and B, but equilibrium potentials (-70mV for A, -50mV for B respectively) are different. Label the axes. (5 marks)· When the equilibrium potentials for both are the same (-40mV) but they have different conductance’s (2pS for A, 4pS for B respectively). Label the axes. (5 marks) Q8. A cell has a membrane potential of – 68 mV with the concentration of an ion [X+] inside (135mM) and concentration outside (8mM). What will be the direction and magnitude of the ECDF? (8 marks) Q9. Consider a situation where K+ ion has an intracellular fluid (ICF) concentration of 320 mM and an extracellular fluid (ECF) concentration of 35 mM. What will be the direction and magnitude of the ECDF acting on K+ at Vm = – 82 mV? (8 marks) Q10. If ICF (K+) ion concentration is 165 mM, what ECF (K+) concentration is required for the condition of no net passive flux of K+ across the membrane at Vm = – 66 mV ? (6 marks) Q11. What is the Donnan Effect? Two solutions are separated by a membrane permeable to sodium and chloride ions. The concentrations on side 1 are sodium = 100 mM and proteins = 100mM and the concentrations on side 2 are sodium = 100 mM and chloride = 100 mM. At steady state approximate the concentrations of the different species and describe the different forces contributing to this steady state. (10 marks) Q12. The concentration of carbon at 1 mm into the surface of the titanium slab is 0.25 kg/m3 and at 3 mm the concentration is 0.68 kg/m3. The temperature of the carburizing environment is 925 degrees Celsius, and the rate at which carbon is entering this 2 mm thick region is 1.27 x 10-9 kg/(m2s). What is the diffusion coefficient for this particular treatment? (6 marks)
by admin | Sep 23, 2022 | Biology | 0 comments
Q1. The table below shows the current recorded from patch clamp experiments on potassium channels…
A professional Academic Service Provider
Distinguished Writers Ensure Accountability, Confidentiality, High-Quality, and Timely Execution
Distinguished Writers comprises of well-trained professionals striving to give our clients an awesome experience. We engage with our customers throughout the learning process to ensure they are comfortable with both their classwork and homework in order to achieve excellent grades. The team is well-balanced across different fields to suit our clients. Our diversified fields include article writing, thesis proposals, project management, coursework, essay writing, and dissertations among others.Fundamental Values
1. Accountability: The company values professionalism in all our undertakings. As such, we interact transparently with our customers.
2. Confidentiality: The company does not disclose anything to third-parties, and our interactions with customers remain confidential.
3. High-Quality The products are thoroughly proofread and counter-checked to ensure they meet the expected quality levels.
Guarantees
4. Quality is a Guarantee: Our writers are accurately matched with their area of expertise to ensure proper quality is maintained. We are also equipped with adequate software to guarantee error-free products.
5. Money Back Policy: As a client-oriented service, we offer 100% refund for the following: if we received a double payment from you; if you placed similar orders twice (or more) and paid for all of them; the writer has not been assigned; you asked to cancel the order within 20 minutes after placing it; an e-Check payment has been sent (the Dispute Manager will contact you accordingly). Other cases involve a comprehensive investigation by the Dispute Department and feedback given within 24 hours. We value our customers; therefore, the process will be fair, fast, and precise.
5 .Free Revisions: You can request for revisions at no additional cost. Nonetheless, this does not include complete change of the initial order instructions and if it is not past ten days upon your approval.
6. 24/7 Customer Support: Our support staff are always online to provide any assistance when needed
Ordering Process
NOTE: If you have any question, always contact our support team before the commencement of your project. ALL THE BEST”:
Recent Comments