What are melanosomes?

• A. Cells that produce keratin
• B. Pigment-carrying granules
• C. Cells that nourish the skin
• D. Small blood vessels in the skin

Answer: (B)

Melanosomes are specialized organelles found within melanocytes, the cells responsible for producing melanin, the pigment that gives color to the skin, hair, and eyes. These organelles function as pigment-carrying granules that store melanin and play a crucial role in determining skin tone and protecting the skin from the harmful effects of ultraviolet (UV) radiation. When melanocytes are activated—often in response to UV light—they produce melanin that is packaged into melanosomes and transferred to surrounding keratinocytes, where it contributes to the skin's pigmentation.

The other options refer to different components and functions within the skin. Cells that produce keratin are keratinocytes, which play a key role in forming the outer barrier of the skin, but they are not involved in pigment production. The option mentioning cells that nourish the skin likely refers to fibroblasts or other cell types involved in maintaining overall skin health, rather than pigment production. Lastly, small blood vessels in the skin pertain to the vascular system and circulation, which provide nutrients to the skin but do not relate to melanin production. Thus, the correct characterization of melanosomes is that they are pigment-carrying granules.