Here is the net photosynthesis equation:

6CO2 + 12H20 + light photons - C6H12O6 + 6H2O + 6O2

We start with six molecules of carbon dioxide + 12 water molecules + photons

We end up with 1 glucose molecule, 6 water molecules and 6 oxygen molecules

Two things to note:

--It is the water molecules that are split, NOTthe CO2 molecule. The CO2 is used to make the glucose molecule.

--Water (H2O) appears on both sides of the equation. The water molecules that come out the other end are not the water molecules that go in. Plants rearrange the atoms.

The equation gives you the general idea of photosynthesis in the sense that saying iron ore, plastic, bauxite, glass, etc go into the making of an Aston Martin. It tells you the raw materials that are the starting point but nothing about how to build a car.

Photosynthesis takes place in little “organelles” called chloroplasts. Physically chloroplasts in land plants appear to be discs about 5 micrometres in diameter. Every leaf cell in a land plant contains 10-100 chloroplasts.

Chloroplasts are exquisitely precise little nano-factories. For decades scientists have been trying to piece together what goes on inside the factory.

One part of the "manufacturing process" requires a manganese-based catalyst. And this is where Vittal Yachandra(1) comes in. He has spent over a quarter of a century trying to figure the structure of this one catalyst.

He explains his work in this youtube video, How Plants Do it: Light, Oxygen, Action! (2)

This is not a slick video. There is no music, no special effects. It’s just a video of a lecture given at Stanford. It provides an insight into how a real scientist spends his time.

This is what most science is about – the patient piecing together of bits of a puzzle to see how they fit into the greater whole. If Dr. Yachandra cracks it he may get a Nobel prize. As you’ll see from the video, he and his team are getting close.

(1) http://pbd.lbl.gov/PBD_web_site/web_site/html/about/people/yachandra.html

(2) http://www.youtube.com/watch?v=jvZ-uAdfKH4

Dear Steven,

Thanks for the links.

Almost as good as watching the Big Bang Theory.

Interesting world you live in.

Thanks Lexi

Yep, science is endlessly fascinating. To quote Steven Weinberg:

>>The effort to understand the universe is one of the very few things which lifts human life a little above the level of farce and gives it some of the grace of tragedy.>>

For those who are interested:

The 12 "output" oxygen atoms (6O2) come from the 12 "input" water molecules.

The 24 hydrogen atoms in the "input" water molecules are split as follows:

--12 end up in the glucose molecule

--12 end up in the "ouput" water molecules.

All six of the carbon atoms in the "input" CO2 end up in the glucose molecule.

of the 12 oxygen molecules in the input CO2, 6 end up in the glucose molecule and 6 in the "output" water molecules.

The "output" water thus gets its hydrogen atoms from the "input" water and its oxygen items from the "input" CO2 molecules.

Here is a link to a youtube video with a 5 minute introduction to what we know about photosynthesis:

http://www.youtube.com/watch?v=hj_WKgnL6MI

And here is a link to a piece explaining the role of the manganese catalyst.

http://www.lbl.gov/Science-Articles/Archive/PBD-water-split.html

And just to demonstrate that this is an ongoing story:

New Twist on Life’s Power Source

http://carnegiescience.edu/news/new_twist_life_s_power_source

Some organisms break the rules.

Stanford, CA — A startling discovery by scientists at the Carnegie Institution puts a new twist on photosynthesis... Photosynthesis by plants, algae, and some bacteria supports nearly all living things by producing food from sunlight, and in the process these organisms release oxygen and absorb carbon dioxide. But two studies by Arthur Grossman and colleagues...suggest that certain marine microorganisms have evolved a way to break the rules—they get a significant proportion of their energy without a net release of oxygen or uptake of carbon dioxide. This discovery impacts not only scientists’ basic understanding of photosynthesis, but importantly, it may also impact how microorganisms in the oceans affect rising levels of atmospheric carbon dioxide.>>

No one expected that!

Dear Steven,

Are there any studies to improve the process of
microorganisms absorbing more carbon as a contribution
to the current carbon pollution concerns?

If nature creates the problem - nature should be
able to resolve the problem.

Aah, a breath of fresh air! Thanks for sharing.

In my brief foray into science at uni, photosynthesis was something that fascinated me. It seemed to me that, if we could duplicate the process, there would be many rewards just waiting to be uncovered. Even if we can't, understanding the process better would give us some opportunities to exploit (hopefully in the positive sense of the word) these little natural factories.