g-protein coupled receptors, taste, and miracle fruit

G-PROTEIN COUPLED RECEPTORS, TASTE, AND MIRACLE FRUIT

LAST NIGHT’S HOMEWORK• Name the 5 types of taste. Explain why each type of

taste was important in human evolution.

Sweet – detecting ripe fruit

Sour – detecting unripe fruit

Bitter – detecting poison

Salty – maintaining water balance

Umami – detecting protein

HOW DO WE TASTE?

Each taste bud is thought to contain all

types of receptors

Sweet

Bitter

Salt

Umami

Sour

control tt Tt TT

221 bp176 bp

45 bp

Nontaster (tt) GGCGGGCACT (221 bp long)

Taster gene (TT) GGCGGCCACT

When cut with restriction enzyme Hae III between GGCC what happens????

TASTE EVOLUTION• Primates have both tasters and nontasters• All monkeys are tasters and don’t taste aspartame as sweet

• Almost all vertebrates can taste sweet and umami• Cats and chickens cannot detect sweet foods• Bats that eat different foods have different genes expressed – fruit bats have active sweet receptor genes and not umami)

PANDASThey are BEARS with large canine teeth with no ability to digest vegetable matter and no chambered stomachs.

Which came first – the preference for bamboo diet or the mutated umami gene???

If the receptor was restored to functional, what effect might this have on the panda?

GCPR FOR TASTE• 1. Bitter

• 2. Sweet

• 3. Umami

LET’S TASTE-TESTMiracle Berries and Gymnema Tea