Photosynthesis: energy capture

Published on October 1, 2007 Reviewed on March 30, 2022   40 min

A selection of talks on Plant & Animal Sciences

Please wait while the transcript is being prepared...
Photosynthesis: Energy Capture. My name is Robert Blankenship from the Departments of Biology and Chemistry at Washington University in St. Louis.
Photosynthesis is a biological process in which plants store the sun's energy in the form of chemical energy. It is the source of all of our food and most of our energy resources.
The basic concept of photosynthesis is that light energy is absorbed by a plant, and chemical processes take place in which carbon dioxide and water are converted into the organic matter of the plant and oxygen is given off as a byproduct.
Photosynthesis takes place on a global scale. This diagram shows a map of the Earth in which the areas that do photosynthesis are color-coded. On land, it is coded in terms of the vegetation index, and you can see the areas with dark green are the most productive. Some areas, like the Sahara desert and the center of Australia, have low productivity, while much of the rest of the landmass has high productivity. The oceans are coded in terms of chlorophyll concentration, there the green color indicates regions of the ocean with high productivity. Approximately equal primary production occurs on land and in the ocean.
Photosynthesis takes place in plants, algae and bacteria. While details differ in the various types of organisms, the basic chemical mechanism of photosynthesis is essentially the same in all organisms that do chlorophyll-based photosynthesis. This mechanism is light-driven electron transfer. We will explore how this works and some of the basic concepts involved in this light energy transduction process during this talk.