Many of the glyceraldehyde 3-phosphate produced by the Calvin cycle in chloroplasts is exported to the cytosol and used to produce the disaccharide, sucrose. 1st the glyceraldehyde 3-phosphate is changed to fructose 6- phosphate and glucose 1-phosphate. The chemical reactions included are essentially a reversal of glycolysis. The glucose 1-phosphate is then chnaged to UDP-glucose and this reacts with fructose 6-phosphate to synthesize sucrose 6-phosphate:
UDP-glucose + fructose 6-phosphate→ sucrose 6-phosphate +UDP
Hydrolysis of the sucrose 6-phosphate yields sucrose. This is the major sugar which is transported between plant cells, analogous to the supply of glucose by the bloodstream to animal tissues.