[Campbell Biology P.261] If a drug were developed that specifically blocked the receptors fo... | Practice Question

If a drug were developed that specifically blocked the receptors for epinephrine on muscle cells, what would be the most likely immediate physiological consequence for an impala attempting to flee a cheetah?

  • A: The impala's brain would not signal the adrenal glands to release epinephrine.
  • B: The impala's heart would pound more rapidly.
  • C: Glycogen in the muscle cells would not be efficiently converted to glucose.
  • D: Relay molecules within the muscle cells would be overactivated.

Explanation

The pathway described shows epinephrine binding to receptors, leading to signal transduction relay molecules, enzyme activation and then cellular response glycogen to glucose for energy . If the receptor is blocked, epinephrine cannot bind, thus the entire downstream pathway, including glycogen breakdown, would be inhibited. The impala would lack the necessary energy for sustained muscle activity.