Q:

What are the reactants of the Calvin cycle?

A:

The reactants in the Calvin cycle are carbon dioxide, water and a sugar with five carbon atoms known as ribulose. The enzyme catalyst RuBisCo and energy donators aAdenosine triphosphate, or ATP, and nicotinamide adenine dinucleotide phosphate, or NADPH, are necessary for the reaction but aren't reactants in the technical sense.

The Calvin cycle is one of the major ways photosynthetic organisms make carbon dioxide and water into sugars, such as glucose and fructose. They do this by combining water and carbon dioxide with ribulose, which produces an intermediate molecule with six carbon atoms. This immediately splits into two molecules with three carbon atoms each, known as phosphoglyceric acid. Energy from ATP is used to strip the phosphate from the acid, and some of the molecules that result are used to make fructose. The remainder is recycled back into ribulose to continue the cycle.

The Calvin cycle takes place in the chloroplast, the same organelle that generates chemical energy from sunlight, but the cycle is not directly involved in that reaction. Instead, the energy is transferred from the parts of the organelle that process the sunlight to the site of the Calvin cycle. The Calvin cycle is one of the most important chemical reactions on earth, and the enzyme catalyst RuBisCo is probably the most common protein in existence.

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Related Questions

  • Q:

    How does the Calvin cycle depend on light reactions?

    A:

    The Calvin cycle depends on light reactions because they power the electron transport necessary to produce ATP, which in turn powers the Calvin cycle. The Calvin cycle is the major method by which plants and algae produce carbohydrates and oxygen from water and carbon dioxide. It is thus one of the most important chemical cycles in nature as the basis of nearly every food chain.

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  • Q:

    What are the products of the Calvin cycle?

    A:

    The final product of the Calvin cycle, the second metabolic cycle of photosynthesis, is the sugar glucose. Carbon dioxide joins with organic molecules to produce glyceraldehyde-3-phosphate. After several glyceraldehyde-3-phosphates are produced from the cycle, they join together to form glucose.

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  • Q:

    When does the Calvin cycle of photosynthesis begin?

    A:

    The Calvin cycle of photosynthesis begins after light energy is transformed into chemical energy by the cells of plants. The adenosine triphosphate, or ATP, molecules created power the Calvin cycle. The Calvin cycle uses the energy to create carbohydrates from water and carbon dioxide.

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  • Q:

    What happens during the Calvin cycle?

    A:

    The Calvin cycle is a metabolic process that occurs in the chloroplasts of plant cells. Its main function is to create sugar from carbon dioxide for the plant to use as a source of energy.

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