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February 8, 2009, 5:40 pm

Photosynthesis in a flash!

That amazing process that plants and some bacteria use to feed themselves - photosynthesis - has fascinated scientists for decades... if only we could understand it to be able, perhaps, to copy it! The understanding is now one step closer thanks to new laser technology

[BBC News]

We rely on photosynthesis for all our food - even the animals we eat have eaten plants as their food - so plants are the producers in the food webs that provide humans with the molecules we need to build our own bodies.

Photosynthesis is a truly remarkable process - electrons are pulled out of water molecules  and are used to make glucose (a sugar). But exactly how this occurs has been difficult to study because laser beams used to take images of how the electrons are moved damage the proteins in the light-capturing complexes.

Now a new laser can take a snapshot of one hundred femtoseconds (ten thousand millionth of the normal camera flash time) ... can you imagine that fast!!!

This technique can "see" how electrons interact with eachother, and has been used to study the light-harvesting LH2 protein complex in photosynthetic bacteria - research that could help understand how photosynthesis works and also to improve the efficiency of solar cells for energy.

A solar cell is a device that converts solar energy into electricity using the photovoltaic effect - but so far the efficiency of plants and bacteria is better!

Video simulation of how molecules help in the light-dependent reactions of photosynthesis in plants


Simple interactive activities for food chains and (scroll down) food webs here

A femtosecond is one quadrillionth of a second, or one thousandth of a nanosecond. To put this in perspective, if you assume that the universe is 12 billion years old, then a femtosecond compares to a second like 10 minutes compares to the life of the universe

- a bit too fast to imagine, so try these activities to find out how quickly you can react  instead!!!