homework help 12451

Just did this in school recently._x005F_xD83D__x005F_xDE42_

In the Calvin Cycle, the inorganic carbon in ##CO_2## is incorporated into organic molecules, initially glycerate 3-phosphate (GP). This is known as Carbon Fixation. The carbon is fixed in organic molecules making it available to other organisms.

This process of carbon fixation is actually the first step in the Calvin Cycle.

1) Carbon dioxide combines with a 5-carbon compound called RuBP( ribulose biphosphate). The reaction is catalysed by the enzyme RuBISCO. This is the most abundant enzyme in the world.

2) A 6-carbon compound is formed, but it is unstable and therefore immediately breaks down into 2 3-carbon molecules, called GP (glycerate 3-phosphate).

3) The Calvin Cycle does continue, but it is not part of Carbon fixation. Still look it up, so you can understand where I am coming from.

It relates to because for each molecule of carbon dioxide that is fixed, two molecules of NADPH and three molecules of ATP from the light reactions during photosynthesis are required.