BHU PMT BHU PMT (Screening) Solved Paper-2005

  • question_answer
    'Adaptation' of eyes in dark is due to :

    A)  depletion of vision pigment in rod

    B)  depletion of vision pigment in cones

    C)  repletion of vision pigment in rods

    D)  repletion of vision pigment in cones

    Correct Answer: C

    Solution :

                     Two types of phoioreceptor cells are present in retina, i'.e., rods and cones. (i) Rods : These cells are active in dark. Rhodopsin a vision pigment is present in rods. In strong light, rhodopsin is bleached due to splitting of its two components i.e., scotopsin and retinal. But is reformed in dim light i.e., dark. (ii) Cones : These cells are active in strong light. lodopsin a pigment is present in cones. These cells produce sharp coloured image in bright light.


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