Reference no: EM133368847

Assignment:

Miraculin is homodimeric protein extracted from the fruit of Synsepalum dulcificum, sometimes referred to as the miracle fruit or miracle berry. After it is dissolved on the tongue, normally sour foods like citrus or vinegar taste sweet. Miraculin does this by binding the hT1R2-hT1R3 sweet receptor located on taste cells on the tongue, and activating the receptor in a pH-dependent manner (i.e. in the presence of the acidic pH of sour foods).

1. How would you expect taste cells of each type to respond to lime juice in the presence of miraculin? How does that compare to your expectations for the patterns of activation produced by lime juice in the absence of miraculin?

2. How would geniculate ganglia neurons respond to lime juice in the presence of miraculin? Be sure to describe how individual geniculate ganglia neurons normally respond to sweet and sour tastes in your answer.

3. Consider the neurons in the anterior portion of gustatory cortex (i.e. "sweet cortex"). How would these neurons normally response to lime juice and how would they respond to lime juice in the presence of miraculin? Please describe the evidence for your answer, including the relevant brain measurement approach(es).

4. If sweet cortex was inactivated, how would that affect your perception of lime juice in the presence of miraculin? Would it still taste sweet? Sour? Please describe the evidence for your answer, including the relevant behavioral tests and brain manipulation approach(es).