Melanocyte Physiology and Biosignaling

The video tutorial covers the function of melanocytes, cells responsible for melanin production, which protects DNA from UV light. It explains the role of alpha-MSH in activating melanocytes through G protein-coupled receptors, leading to adenylate cyclase activation and cyclic AMP production. This biochemical pathway involves protein kinase A and transcription factors like CREB, MITF, and P300, which regulate melanin synthesis and cell survival. The video also discusses melanosomes, the organelles where melanin is synthesized, and the types of melanin, eumelanin and pheomelanin, produced in different melanosomes.

What is the primary function of melanin in the skin?

• To regulate body temperature

• To produce vitamin D

• To protect DNA from UV light

• To provide nutrients to skin cells

Which hormone is responsible for stimulating melanocytes?

• Alpha melanocyte stimulating hormone

• Growth hormone

• Thyroid hormone

• Insulin

What type of receptor does alpha MSH bind to on melanocytes?

• Enzyme-linked receptor

• Ion channel receptor

• G protein-coupled receptor

• Nuclear receptor

What is the role of adenylate cyclase in the melanin synthesis pathway?

• It converts ATP to cyclic AMP

• It transports melanin to the skin surface

• It breaks down melanin

• It inhibits protein kinase A

Which molecule activates protein kinase A in the melanin synthesis pathway?

• RNA

• DNA

• ATP

• Cyclic AMP

Which transcription factor is phosphorylated by protein kinase A?

• MITF

• CREB

• SOX10

• PAX3

What is the function of BCL-2 in melanocytes?

• To inhibit melanin synthesis

• To promote cell division

• To prevent apoptosis

• To enhance melanin degradation

Where does melanin synthesis occur within the melanocyte?

• Nucleus

• Cell membrane

• Cytosol

• Melanosomes

Which type of melanin is responsible for a reddish tint in hair?

• Eumelanin

• Pheomelanin

• Neuromelanin

• Allomelanin

What is the primary role of melanocyte dendrites?

• To synthesize melanin

• To transfer melanin to other cells

• To store nutrients

• To produce hormones