Final answer:
Gymnemic acids from the plant Gymnema sylvestre bind to sweet taste receptors on the tongue, inhibiting the perception of sweetness by preventing sugar molecules from activating these receptors. This interaction can be modeled by having gymnemic acid molecules attached to sweet receptors in a diagram of the taste buds. Bitter taste and the gag reflex, primarily mediated by the posterior part of the tongue and different receptors, are not directly affected by gymnemic acids.
Step-by-step explanation:
To create a model showing how gymnema affects the taste receptors on the tongue, we must understand the taste transduction pathways. The primary tastes include salty, sour, sweet, bitter, and umami. Sweet taste receptors bind to G protein-coupled receptors when they encounter sugar molecules such as glucose, leading to the depolarization of gustatory cells and the perception of sweetness.
Gymnemic acids from the plant Gymnema sylvestre are known to interact with sweet receptors. Once gymnemic acids bind to these receptors, they interfere with the activation by sugar molecules, thereby temporarily inhibiting the sweet taste. In such a model, the taste buds would show the gymnemic acid molecules bound to the sweet receptors, preventing glucose or other sugars from binding and activating the G protein-coupled receptors.
In the context of bitter taste, the reception is primarily located in the posterior part of the tongue, where a gag reflex can prevent the ingestion of potentially poisonous substances. This area receives sensory input from the glossopharyngeal and vagus nerves. When gymnemic acids are applied to the tongue, this may modulate the taste receptors response to sweet by blocking the receptor's activation, which is not directly related to the bitter taste and gag reflex.