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     1.2 +++ b/test.tex	Mon Sep 27 16:57:26 2010 -0400
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     1.4 +Photoreceptors in the retina (such as cones) have special channels that are open to Na+ in the dark. When light hits photoreceptors, these special channels close. What can you conclude from this? 
     1.5 +a) Photoreceptors depolarize to light. 
     1.6 +b) Photoreceptors hyperpolarize to light. 
     1.7 +c) Photoreceptor voltage does not change in the presence of light.
     1.8 +d) None of the above
     1.9 +
    1.10 +
    1.11 +What happens in a photoreceptor cell (a rod, for example) in response to a light stimulus?
    1.12 +a) rod membrane depolarizes because Na+ channels open as a result of a decrease in second messenger cGMP
    1.13 +b) rod membrane hyperpolarizes because K+ channels open as a result of a decrease in second messenger cGMP
    1.14 +c) rod membrane hyperpolarizes because Na+ channels close as a result of a decrease in second messenger cGMP
    1.15 +d) rod membrane depolarize because K+ channels close as a result of a increase in second messenger cGMP
    1.16 +
    1.17 +
    1.18 +A difference between rods and cones is:
    1.19 +a) Rods hyperpolarize to light, while cones depolarize to light
    1.20 +b) Rods are much larger than Cones, and more numerous.
    1.21 +c) Cones and rods use different types of opsins
    1.22 +d) The total volume of all Cones is smaller than that of Rods
    1.23 +
    1.24 +
    1.25 +
    1.26 +
    1.27 +
    1.28 +
    1.29 +To approximate an ideal OpAmp, all OpAmps should:
    1.30 +
    1.31 +a) have almost infinite positive open loop gain
    1.32 +b) have almost infinite negative open loop gain
    1.33 +c) have almost infinite positive output drift
    1.34 +d) have almost infinite negative output drift
    1.35 +
    1.36 +
    1.37 +
    1.38 +
    1.39 +
    1.40 +Normal OpAmps all approximate an ideal OpAmp. An Ideal OpAmp:
    1.41 +
    1.42 +I 		Has infinite positive open loop gain
    1.43 +II		Has zero open loop gain
    1.44 +III 	Is an IC
    1.45 +IV		Has zero output drift
    1.46 +V		Has output drift of -1
    1.47 +
    1.48 +
    1.49 +a) I,III,V
    1.50 +b) II,III,V
    1.51 +c) II,V
    1.52 +d) I,IV
    1.53 +
    1.54 +
    1.55 +
    1.56 +
    1.57 +A difference between the 741 OpAmp and the K2-W OpAmp is:
    1.58 +
    1.59 +a) the 741 has a large negative open loop gain while the K2-W has a large positive open loop gain
    1.60 +b) the 741 is an IC while the K2-W is not
    1.61 +
    1.62 +
    1.63 +
    1.64 +
    1.65 +
    1.66 +
    1.67 +I 
    1.68 \ No newline at end of file