Which of the following facts accounts for the variation in skin tone that exists between individuals?
A)
Someone with dark skin has more melanocytes in his or her skin layers.
B)
Darker-skinned individuals have melanosomes that produce melanin faster.
C)
Dark skin is associated with spherical melanosomes, which produce and "package" pigment differently.
D)
Greater numbers of keratinocytes result in darker skin tone.
Ans:
B
Feedback:
The amount of melanin in the keratinocytes determines a person's skin color. Dark-skinned and light-skinned people have the same amount of melanocytes. However, in dark-skinned people, larger melanosomes are produced and transferred to the keratinocyte individually. In light-skinned people, a number of smaller melanosomes are packaged together in a membrane and then transferred to the keratinocyte. The way the melanosomes are packaged is responsible for the pigmentation in darker-skinned persons. Darker-skinned people do not have more melanocytes than light-skinned people, but the production and packaging of pigment is different.
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