[Campbell Biology P.929] The text states that hormones are broadcast throughout the body via... | Practice Question

The text states that hormones are broadcast throughout the body via the bloodstream. How do these signaling molecules exert their specific effects only on certain target cells?

  • A: Hormones are actively transported by special carriers directly to target cells, avoiding non-target cells.
  • B: Target cells possess specific receptor molecules that recognize and bind only to particular hormones, initiating a response.
  • C: Hormones are quickly degraded everywhere in the body except at the sites of their target cells, limiting their range.
  • D: Only target cells have the necessary enzymes to synthesize and release hormones, creating a localized effect.

Explanation

The text explicitly states: 'Different hormones cause distinct effects, and only cells that have receptors for a particular hormone respond Figure 40.6a .' This 'lock and key' mechanism ensures that despite hormones traveling everywhere, only cells with the correct receptor will initiate a response.