Step 2 each PGA molecule receives a phosphate group from ATP each PGA molecule receives a hydrogen from NADPH+ releases 2 phosphate groups Side products: used in light reactions to synthesize new molecules of ATP and NADPH+ ADP NADP+ phosphate 2 PGALs are produced phosphoglyceraldehyde 3-carbon In short: phosphates, energy, and hydrogen are added to PGA to form PGAL side products return to light reaction