Topic Set 5: Melanin & Skin Pigmentation

What factors determine skin color?

Pigments (melanin, hemoglobin, carotene) and UV radiation

How does UV radiation affect skin color?

Increases melanin production to darken skin

Where is melanin made and packaged?

Made by melanocytes and packaged into melanosomes

What is a melanosome?

A vesicle that contains melanin

What two substances are required for melanin production?

Tyrosine and tyrosinase

What is the function of tyrosinase?

Links tyrosines together to form melanin

How does melanin protect epidermal cell DNA?

Surrounds the nucleus to shield DNA from UV radiation

Why is UV damage to nuclear DNA dangerous?

Mutates DNA and causes skin cancer

How does melanin affect vitamin D synthesis?

Decreases vitamin D synthesis

What determines the amount of melanin an individual produces?

Genetics

Does the total number of melanocytes differ between skin tones?

No

What causes differences in skin tone?

Amount of melanin produced, and size and number of melanosomes

What effect does more melanin have on skin tone?

Darker skin tone