Final answer:
It is false that bitter-taste receptors do not depolarize when activated. Some bitter molecules lead to depolarization while others cause hyperpolarization, affecting the activation of G proteins in the gustatory cells and influencing the generation of action potentials.
Step-by-step explanation:
The statement that bitter-taste receptors do not depolarize when activated is false. Bitter taste is detected by food molecules binding to G protein-coupled receptors on the taste buds. There is a wide variety of bitter compounds, and they can cause different reactions in gustatory cells. Some bitter substances lead to depolarization of gustatory cells, which is an essential step in the process of taste perception as it leads to the generation of an action potential. Other bitter substances might hyperpolarize the cells instead. The outcome, either an increase in G protein activity or a decrease, is dependent on the specific bitter substance.
An essential detail to understand is that depolarization is necessary for the gustatory cell to fire an action potential. If the depolarization does not reach the threshold level, generally around -55mV, an action potential will not be generated, and the taste signal will not be transmitted to the brain. As some bitter molecules can cause depolarization, it is not correct to state that bitter-taste receptors do not depolarize when activated.