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