4: Three resistors are placed in a circuit as shown. What is the equivalent resistance between the points A and B? 3002 20 Ω 15 Ω B 5- ○ a) 30 £2 b) 65 ₤2 ◎c) 15 ○ d) 35 £ Ω e) 20 £2

123. Read the following flow regarding to voltage :- 55mv → 0 mv → -70 mv- +30 mv A (B) D) at which potential Na*-K* pump is closed :- (1) A (2) A & B (3) В & C (4) A & D

Patch clamp recording of a single ion channel yields the following results:         Holding Potential (mV) Measured Current (pA) -100 -1.0 -50 0.0 0 +1.0 +50 +2.0 +100 +3.0 Part a. What is the equilibrium potential for ion X+1? a.) 0 mv  b.)+55 mv c.)-50 mv d.) -60 mv  e.) -75 mv Part b. Is ion X+1 in higher concentration inside or outside the cell? a.) inside  b.) outside  Part c.  Calculate the membrane potential at the instant when a neuron has the following relative permeabilities: PK+ = 1.0, PNa+ = 1.0, PCl- = 1.0.  Use the ionic concentration values in the picture included.  a.) -12 mv  b.) -35mv  c.) -60 mv  d.) +20 mv  e.) 0 mv

18. How much voltage would be necessary to generate 10 amps of current in a circuit that has 5 ohms of resistance? 50 2 25 0.5