Final answer:
The Miracle Fruit, Synsepalum dulcificum, impacts taste by binding to sweet receptors, which changes how acidic foods are perceived, making them taste sweet when the fruit's active compound miraculin is activated at a lower pH level. The taste alteration occurs due to the activation of G protein-coupled receptors involved in sweet, bitter, and umami taste perception.
Step-by-step explanation:
The Miracle Fruit, Synsepalum dulcificum, affects taste by binding to sweet receptors on your taste buds, temporarily making acidic foods taste sweet. When the active compound in Miracle Fruit, miraculin, comes in contact with the tongue, it binds to the sweet receptors. Normally, these receptors are activated by monosaccharides like glucose, fructose, and artificial sweeteners such as aspartame, or saccharine. However, when the pH level on the tongue is lowered by the consumption of an acidic substance, miraculin changes its shape, thus activating the sweet receptors, resulting in the perception of sweetness instead of sourness, which is typically triggered by acids like citric acid in sour fruits.
The key to the effect of Miracle Fruit lies in the way it interacts with the G protein-coupled receptors that are responsible for sweet, bitter, and umami tastes. These receptors, when activated by appropriate molecules, initiate a signal transduction system leading to the depolarization of the gustatory cell, transmitting the taste signal to the brain. For sweet and umami tastes, molecules like glucose and the amino acid L-glutamate, respectively, activate these receptors, while a large diversity of bitter-tasting molecules might either depolarize or hyperpolarize gustatory cells.