Final answer:
A response inside the cell can indeed be turned “on” or “off” by hormones which act as chemical messengers. The regulation is controlled by receptors and signaling pathways, which are complex and specific to the needs of the organism.
Step-by-step explanation:
When considering how a response within a cell is turned “on” or “off,” it involves a complex signaling pathway. Hormones are chemical messengers that alter conditions inside the cell, often in response to some external stimuli. They must indeed be activated and deactivated at specific times based on the needs of the organism. The regulation of hormones and their responses is typically controlled by a variety of mechanisms, including the presence of specific receptors on the surface of cells and the activation or inhibition of signaling pathways within the cell.
For example, when a hormone binds to a receptor on the cell surface, it triggers a series of reactions inside the cell that result in the “on” response, like the expression of certain genes or activation of enzymes. Conversely, the removal of the hormone or the binding of another molecule that inhibits the signaling pathway can turn off the response.
Therefore, the statement that a response is simply turned “on” and “off” is true in the context of cellular responses to hormones, but the mechanisms involved are highly intricate.