The Calvin Cycle Do Now 1.Complete diagram at left.

1 – minute review Photosynthesis is the process most autotrophic organisms use to capture energy and build carbohydrates. It requires light, CO 2, and H 2 O. It produces sugar and oxygen. The light reactions capture solar energy, and store it in the energy carrier molecules ATP and NADPH, which are needed to power the Light-Independent Reactions, aka the Calvin Cycle

The Calvin Cycle The Calvin Cycle (named after its discoverer) is the biochemical pathway that produces fixed carbon, in the form of glucose. Carbon fixation is the process of bonding carbon to organic compounds.

The Calvin Cycle takes place in the stroma of the chloroplasts

RUBISCO Rubisco is the enzyme that fixes CO 2 from the atmosphere in green plants. As such, it is arguably THE most important biological enzyme on Earth.

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Recap The Calvin Cycle is the most common pathway plants use for carbon fixation. Cabon fixation is the process of using CO2 from the air to build organic compounds. It takes a lot of energy from the light reactions to power the Calvin Cycle (detail: 18 ATP & 12 NADPH for 1 molecule of glucose!)

The Rate of Photosynthesis Several factors can affect the speed at which photosynthesis happens. Most importantly, light and temperature.

The Effect of Light Intensity and CO 2 Concentration As light and CO 2 increases, the rate of photosynthesis increases to a maximum

The Effect of Temperature There is an optimum temperature at which photosynthesis happens as fast as possible

What’s Next? Tomorrow: other forms of carbon fixation.