Question

11. Within the light-independent reactions, what can be said about the 3-carbon-atom molecules produced?

Answer 1

The 3 - carbon molecules formed in the light independent reactions of photosynthesis are important precursors to the main products of photosynthesis namely glucose, starch and cellulose. They are necessary for making these end products

The 3 - carbon molecules that are formed are:

1. 3- phosphoglycerate (3-PGA) - formed in the first stage of light independent reactions when a molecule of carbon dioxide gas is attached to a molecule of ribulose. The newly formed 6 -carbon sugar quickly breaks down  into two identical 3 carbon molecules, 3 -PGA.

2. Glyceraldehyde 3 phosphate (G3P) - formed when one phosphate molecule is removed from 3 - PGA. 

G3P is then used to make glucose, sucrose, starch, cellulose and other carbohydrates essential for the plant.