BME365R Homework #3

Due September 14, 2004

 

    1. Silverthorn, question 4, p. 166

 

    1. Silverthorn, question 8, p. 166

 

    1. Silverthorn, question 20, p.167

 

    1. Michael and Rovick, Problem 2, pages 21-22

 

    1. Michael and Rovick, Problem 4, pages 26-27

 

    1. After they have influenced the receptors in the post-synaptic membrane, those neurotransmitter molecules which are not broken down by enzymes diffuse back to the pre-synaptic membrane, which lies 20 nm away, with a diffusion coefficient which has been determined to be 5 x 10-6 cm2s-1.  How long does it take the molecules to make this short journey?

 

    1. Assume a membrane is only permeable to calcium.  Derive the expression for the flow of calcium.  Find the Nernst potential for calcium.

 

    1. Suppose a membrane is given with RK = 0.1kW, RNa = 2kW, RCl = 0.25 kW, VK = -74 mV, VNa = 55 mV and VCl = -68 mV.  (a)  Draw the circuit.  (b)  Find the resting membrane potential. 

 

    1. Suppose a membrane has an active Na-K pump with RK = 0.1kW, RNa = 2kW, RCl = 0.25 kW, VK = -74 mV, VNa = 55 mV and VCl = -68 mV.  (a) Draw the circuit. (b) Find INa and IK for the active pump.  (c)  Estimate the rate of energy consumption of the active pump.