What process occurs when a hormone binds to its receptor and triggers a cascade of changes inside the cell?

• A. Gene activation
• B. Endocrine glands
• C. Target cells
• D. Pheromones

Answer: (A)

When a hormone binds its receptor, it starts a signaling cascade inside the cell. This cascade often ends by activating transcription factors that turn specific genes on or off, leading to changes in which proteins the cell makes—i.e., gene activation. This is a common way hormones bring about longer-term cellular changes.

Endocrine glands are the organs that produce hormones, not the intracellular process. Target cells are the cells that respond to the hormone, not the signaling mechanism itself. Pheromones are external chemical signals used for communication between organisms, not the inside-the-cell cascade described here.