biol 1103 calvin cycle

carbon fixation

:the process of converting inorganic CO2 gas into organic compounds

Calvin cycle

:the reactions of photosynthesis that use the energy stored by the light-dependent reactions to form glucose and other carbohydrate molecules

What is the molecule that leaves the Calvin cycle to be converted into glucose?

ADP G3P RuBP 3-PGA B

Which part of the Calvin cycle would be affected if a cell could not produce the enzyme RuBisCO?

None of the cycle could take place, because RuBisCO is essential in fixing carbon dioxide. Specifically, RuBisCO catalyzes the reaction between carbon dioxide and RuBP at the start of the cycle.

Explain the reciprocal nature of the net chemical reactions for photosynthesis and respiration.

Photosynthesis takes the energy of sunlight and combines water and carbon dioxide to produce sugar and oxygen as a waste product. The reactions of respiration take sugar and consume oxygen to break it down into carbon dioxide and water, releasing energy. Thus, the reactants of photosynthesis are the products of respiration, and vice versa.

Section Summary

Using the energy carriers formed in the first stage of photosynthesis, the Calvin cycle reactions fix CO2 from the environment to build carbohydrate molecules. An enzyme, RuBisCO, catalyzes the fixation reaction, by combining CO2 with RuBP. The resulting six-carbon compound is broken down into two three-carbon compounds, and the energy in ATP and NADPH is used to convert these molecules into G3P. One of the three-carbon molecules of G3P leaves the cycle to become a part of a carbohydrate molecule. The remaining G3P molecules stay in the cycle to be formed back into RuBP, which is ready to react with more CO2. Photosynthesis forms a balanced energy cycle with the process of cellular respiration. Plants are capable of both photosynthesis and cellular respiration, since they contain both chloroplasts and mitochondria.

Which statement correctly describes carbon fixation?

the conversion of CO2 to an organic compound the use of RUBISCO to form 3-PGA the production of carbohydrate molecules from G3P the formation of RuBP from G3P molecules the use of ATP and NADPH to reduce CO2 A

Where in eukaryotic cells does the Calvin cycle take place?

thylakoid membrane thylakoid space stroma granum C