# Photosynthesis and leaves

1. Oct 10, 2014

### Maylis

So I was thinking, in the process of photosynthesis

$CO_{2} + 6H_{2}O \xrightarrow{light} C_{6}H_{12}O_{6} + 6O_{2}$

Where is the glucose being deposited in the leaf tissue? Also, why aren't leaves sweet if I were to eat them, considering they are making sugar!!

2. Oct 10, 2014

### Simon Bridge

The glucose gets burned as energy to help the plant grow.
Excess glucose is stored int he leaves and other parts of the plant as starch: think where potatoes get all that starchy goodness from?
Glucose is transported around the plant in sap - think: Maple syrup.
Some leaves do taste sweet. But generally plants don't want animals eating their leaves and sap and so on, so they add other stuff to them to make them taste bad and maybe make them poisonous.

3. Oct 10, 2014

### Torbjorn_L

Intriguing question.

First I note that the anabolic carbon from photosynthesis isn't all destined to become C6 sugars. It starts out as phosphated C3 sugars:

Then there is the RuBP regeneration:

[ http://en.wikipedia.org/wiki/Light-independent_reactions#Calvin_Cycle]

I don't know how sweet C3 sugars are, and if cells would chose to export them. Obviously the mitochondria expects hexoses rather than trioses, so the internal cellular use would rely on C6 production.

I think Simon's response covers the rest of this.