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More Than 475 Free MCAT Questions with Detailed Answers!


MCAT Question A Day - 3/26/14 - Answer!

In the rod cells of the retina of a mammal, the conjugated protein rhodopsin is present. The prosthetic group of rhodopsin is 11-cis-retinal:

When light impinges on the retina, 11-cis-retinal is transformed into 11-transretinal:

Energy is then required to convert the trans isomer back into the less stable cis isomer. The difference in stability of the two isomers is due to

A.  an inductive effect.
B.  a resonance effect.
C.  an isotope effect.
D.  steric hindrance.

The correct answer is (D).
