Student Id: 123456
Name: Joan Dow
Course: Biology 99
Instructor: Brian Einstein
Photosynthesis is the physico-chemical process by which plants, algae and photosynthetic
bacteria use light energy to drive the synthesis of organic compounds. In plants, algae and
certain types of bacteria, the photosynthetic process results in the release of molecular
oxygen and the removal of carbon dioxide from the atmosphere that is used to synthesize
carbohydrates (oxygenic photosynthesis). Other types of bacteria use light energy to
create organic compounds but do not produce oxygen (anoxygenic photosynthesis).
Photosynthesis provides the energy and reduced carbon required for the survival of
virtually all life on our planet, as well as the molecular oxygen necessary for the survival
of oxygen consuming organisms1 . In addition, the fossil fuels currently being burned to
provide energy for human activity were produced by ancient photosynthetic organisms.
Although photosynthesis occurs in cells or organelles that are typically only a few
microns across, the process has a profound impact on the earth's atmosphere and climate.
Each year more than 10% of the total atmospheric carbon dioxide is reduced to
carbohydrate by photosynthetic organisms. Most, if not all, of the reduced carbon is
returned to the atmosphere as carbon dioxide by microbial, plant and animal metabolism,
and by biomass combustion. In turn, the performance of photosynthetic organisms
depends on the earth's atmosphere and climate. Over the next century, the large increase
in the amount of atmospheric carbon dioxide created by human activity is certain to have
a profound impact on the performance and competition of photosynthetic organisms.
Knowledge of the physico-chemical process of photosynthesis is essential for
understanding the relationship between living organisms and the atmosphere and the
balance of life on earth. Several books on photosynthesis are available for the uninitiated
(Hall and Rao, 1994; Lawlor, 1993; and Walker, 1992) or advanced student (Govindjee,
1982; Amesz, 1987; Briggs, 1989; Barber, 1992; Scheer, 1991; Bryant, 1994;
Blankenship et al. 1995; Amesz and Hoff, 1996, Baker, 1996; and Ort and Yocum, 1996).
Taiz and Zeiger (1991) place the photosynthetic process in the context of over all plant
physiology, and Cramer and Knaff (1991) describe the bioenergetic foundation of
The overall equation for photosynthesis is deceptively simple. In fact, a complex set of
physical and chemical reactions must occur in a coordinated manner for the synthesis of
carbohydrates. To produce a sugar molecule such as sucrose, plants require nearly 30
distinct proteins that work within a complicated membrane structure. Research into the
mechanism of photosynthesis centers on understanding the structure of the photosynthetic
components and the molecular processes that use radiant energy to drive carbohydrate
synthesis. The research involves several disciplines, including physics, biophysics,