Mercurial > rlmcintyre

     1 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? 

     2 a) Photoreceptors depolarize to light. 

     3 b) Photoreceptors hyperpolarize to light. 

     4 c) Photoreceptor voltage does not change in the presence of light.

     5 d) None of the above

     6 

     7 

     8 What happens in a photoreceptor cell (a rod, for example) in response to a light stimulus?

     9 a) rod membrane depolarizes because Na+ channels open as a result of a decrease in second messenger cGMP

    10 b) rod membrane hyperpolarizes because K+ channels open as a result of a decrease in second messenger cGMP

    11 c) rod membrane hyperpolarizes because Na+ channels close as a result of a decrease in second messenger cGMP

    12 d) rod membrane depolarize because K+ channels close as a result of a increase in second messenger cGMP

    13 

    14 

    15 A difference between rods and cones is:

    16 a) Rods hyperpolarize to light, while cones depolarize to light

    17 b) Rods are much larger than Cones, and more numerous.

    18 c) Cones and rods use different types of opsins

    19 d) The total volume of all Cones is smaller than that of Rods

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    26 To approximate an ideal OpAmp, all OpAmps should:

    27 

    28 a) have almost infinite positive open loop gain

    29 b) have almost infinite negative open loop gain

    30 c) have almost infinite positive output drift

    31 d) have almost infinite negative output drift

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    37 Normal OpAmps all approximate an ideal OpAmp. An Ideal OpAmp:

    38 

    39 I 		Has infinite positive open loop gain

    40 II		Has zero open loop gain

    41 III 	Is an IC

    42 IV		Has zero output drift

    43 V		Has output drift of -1

    44 

    45 

    46 a) I,III,V

    47 b) II,III,V

    48 c) II,V

    49 d) I,IV

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    54 A difference between the 741 OpAmp and the K2-W OpAmp is:

    55 

    56 a) the 741 has a large negative open loop gain while the K2-W has a large positive open loop gain

    57 b) the 741 is an IC while the K2-W is not

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    64 I
author	Robert McIntyre <rlm@mit.edu>
date	Mon, 27 Sep 2010 16:57:26 -0400
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