AP BIOLOGY

Detailed explanation-1: -In stage 3, RuBP, the molecule that starts the cycle, is regenerated so that the cycle can continue. Only one carbon dioxide molecule is incorporated at a time, so the cycle must be completed three times to produce a single three-carbon GA3P molecule, and six times to produce a six-carbon glucose molecule.

Detailed explanation-2: -These energy-carrying molecules travel into the stroma where the Calvin cycle reactions take place. In plants, carbon dioxide (CO2) enters the chloroplast through the stomata and diffuses into the stroma of the chloroplast-the site of the Calvin cycle reactions where sugar is synthesized.

Detailed explanation-3: -The Calvin cycle reactions can be divided into three main stages: carbon fixation, reduction, and regeneration of the starting molecule.

Detailed explanation-4: -The remaining G3P molecules regenerate RuBP, which enables the system to prepare for the carbon-fixation step. ATP is also used in the regeneration of RuBP. Figure 5.15 The Calvin cycle has three stages.