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Title: What products of the light-dependent reactions are important to the light-independent reaction? Post by: davashkai on Sep 9, 2012 Explain how these products are used in the Calvin Cycle.
Title: What products of the light-dependent reactions are important to the light-independent reaction? Post by: jules_78 on Sep 9, 2012 The products are ATP and NADPH, they are used to make the glucose(sugar)
Title: What products of the light-dependent reactions are important to the light-independent reaction? Post by: irina on Sep 9, 2012 Products of the light-dependent reactions vital to the dark reactions include ATP, and NADPH.
NADPH is generated in the light-dependent reactions as a powerful reducing agent. In the Calvin cycle, it is responsible for the reduction of 1,3-bisphosphoglycerate (1,3-BPG) into glyceraldehyde-3-phosphate. If you are familiar with organic chemistry, it is very hard to reduce a carboxylic acid (glycerate is a carboxylic acid) directly to an aldehyde (glyceraldehyde is an aldehyde) directly. Even if we go through the primary alcohol intermediate, it still involves very nasty reagents such as LiAlH4 (lithium aluminum hydride) and Collins reagent (chromium (VI) oxide with pyridine) which are extremely damaging and toxic to living organisms. Plants, however, overcome this difficulty with clever use of activation by phosphorylation (with ATP) and then an NADPH reduction catalyzed by G3P dehydrogenase. Simply put- The NADPH is used in the Calvin Cycle to reduce compounds in the reaction cycle. This creates sugars for use in the plant. Hoorah for diagrams: http://library.thinkquest.org/C004535/calvin_cycle.html |