2. Today
Taste
Experiments/projects

3. Bumps on your tongue are NOT taste buds
Few. At the back of tongue
Taste buds
Most common type
NO taste buds
Taste buds
Taste buds

4. Papillae
Increase surface area of tongue
Makes tasting ‘easier’

5. Taste Buds Chemo receptors ‘down inside’ papillae
Some also produce saliva

6. Taste Buds

7. Taste Sweet, Salty, Sour, Bitter, Umami(amino acids, proteins)
Receptor proteins on/in taste buds are coded for via genes
Mutations (and gene duplications) happen
You get variation among and between individuals and groups

8. Taste Sweet – your body needs sugar
Umami – protein (proteins can also taste sweet)
Salt – need salts (Na+, K+, etc.)
Sour – “bad” or ‘rotting’ food - acid
Bitter – poison, “bad” food
Fat usually tastes “sweet”

9. Taste What you can taste has evolved within groups/species
Cats – can’t taste sweet
No cat can – lion, tiger, house cat, etc.
Appears to have happened at least different times

10. Taste Pandas – NO umami They eat bamboo
No/little protein – no need to taste it
Most birds can’t taste sweet
One group (hummingbirds) regained ability

11. Taste Dolphins – No bitter OR umami receptors But mostly meat diet…
Swallow meals whole – no need to ‘taste’

12. Taste Humans – Some can taste bitter better than others
Helps avoid alkaloids/poisons
Also helps avoid foods that interrupt thyroid function
“We” can produce up to 25 different bitter receptors (25 different genes)
Dogs – 16
Rats- 37!

13. Taste Humans – Some can taste bitter better than others
Variation within populations
PTC – Phenylthiocarbamide
You either taste it, or you don’t

14. Taste Humans – Some can taste bitter better than others
Variation within populations
PTC – Phenylthiocarbamide
You either taste it, or you don’t
Do YOU taste it?

15. Taste
How about ‘spicy’ foods?

16. Homework
Quiz on how taste and smell work tomorrow?