Answer
Hypothesis:
UV radiation from the sun causes the production of more melanosomes by melanocytes. These are captured by keratinocytes, resulting in skin darkening.
Experimental design:
A part of the skin would be exposed to UV radiation for a specific duration, and another part would be protected. Samples from both skin regions can be taken and visualized under the microscope to evaluate the number of melanosomes in melanocytes. The hypothesis can be accepted if there is a significant increase in the number of melanosomes in the skin region exposed to UV light.
Work Step by Step
The melanin pigment present in the skin is responsible for skin darkening on exposure to the sun. It is produced in melanosomes that are present in melanocytes. Pigment globules are released by protoplasmic extensions of melanocytes and are taken up by microvilli of keratinocytes in the epidermal layer of the skin via phagocytosis.
