[Campbell Biology P.269] Aldosterone is a hormone that circulates throughout the body but on... | Practice Question

Aldosterone is a hormone that circulates throughout the body but only affects kidney cells. Based on the information about intracellular receptors, what is the most logical explanation for this specificity?

  • A: Aldosterone is a very large molecule and can only enter kidney cells.
  • B: Kidney cells are the only cells that produce aldosterone.
  • C: Only kidney cells possess the specific intracellular receptors for aldosterone.
  • D: Aldosterone is rapidly degraded in all other cell types before it can exert an effect.

Explanation

The text clearly states that aldosterone travels throughout the body, but a response occurs only in kidney cells 'because they alone contain receptors for aldosterone.' This highlights the principle of receptor specificity: a cell can only respond to a signaling molecule if it possesses the specific receptor to which that molecule can bind.