Question

in the second stage of photosynthesis, the calvin cycle, once some of the reactants are used they are

Answer 1

The Calvin cycle utilizes ATP and NADPH to transform CO2 into glucose, with most of the intermediate molecules being recycled to regenerate RuBP, enabling continuous glucose production.

Step-by-step explanation:

Understanding the Calvin Cycle in Photosynthesis

The Calvin cycle is the second stage of photosynthesis involving the production of glucose from carbon dioxide. It uses the chemical energy stored in ATP and NADPH, which were produced during the light-dependent reactions. The Calvin cycle has three main stages: carbon fixation, reduction, and regeneration of ribulose bisphosphate (RuBP).

In the initial stage, carbon dioxide is fixed into a stable intermediate. Then, ATP and NADPH provide energy to reduce this fixed carbon and transform it into the sugar glucose. Finally, during the regeneration stage, most of the molecules created are used to regenerate RuBP, which is necessary for the cycle to continue.

Specifically, every three turns of the Calvin cycle produce six molecules of glyceraldehyde-3-phosphate (G3P). Out of these, five are used to regenerate RuBP, and only one G3P molecule is exported to the cytoplasm to contribute to the formation of glucose and other compounds needed by the plant. This efficient recycling of molecules within the Calvin cycle enables plants to continuously synthesize glucose as long as they have the necessary inputs from the light-dependent reactions and from the environment in the form of CO2.

Answer 2

In the Calvin Cycle, which is the second stage of photosynthesis, some of the reactants are regenerated as the cycle progresses. The primary reactant consumed and then regenerated is ribulose-1,5-bisphosphate (RuBP). RuBP is a five-carbon sugar that combines with carbon dioxide in the initial step of the Calvin Cycle, facilitated by the enzyme (RuBisCO).

The Calvin Cycle can be summarized in three main stages:

Carbon Fixation: In this phase, carbon dioxide is added to RuBP, resulting in the formation of a 3-carbon compound.

Reduction: The 3-carbon compounds undergo a series of chemical reactions, ultimately leading to the production of glyceraldehyde-3-phosphate (G3P), a three-carbon sugar. In this process, ATP and NADPH (products of the light-dependent reactions) are used to convert the 3-carbon compounds.

Regeneration of RuBP: Some of the G3P molecules are used to regenerate RuBP, ensuring that the Calvin Cycle can continue. This regeneration step involves additional chemical reactions and consumes ATP.