AP BIOLOGY

Detailed explanation-1: -The majority of plants produce 3-carbon acid called 3-phosphoglyceric acid (PGA) as a first product during carbon dioxide fixation. Such a pathway is known as the C3 pathway which is also called the Calvin cycle.

Detailed explanation-2: -3-Phosphoglyceric acid (3PG, 3-PGA, or PGA) is the conjugate acid of 3-phosphoglycerate or glycerate 3-phosphate (GP or G3P). This glycerate is a biochemically significant metabolic intermediate in both glycolysis and the Calvin-Benson cycle. The anion is often termed as PGA when referring to the Calvin-Benson cycle.

Detailed explanation-3: -The G3P is ultimately converted to glucose. Every 3 cycles of the Calvin Cycle (light independent reaction), 6 molecules of G3P are produced; only 1 is used to produce glucose. The remaining 5 molecules of G3P are used to regenerate RuBP to allow the Calvin Cycle to continue.

Detailed explanation-4: -Since the first stable compound in Calvin cycle is a 3 carbon compound (3 phosphoglyceric acid), the cycle is also called as C3 cycle. The reactions of Calvin’s cycle occur in three phases.

Detailed explanation-5: -In the second stage, ATP and NADPH are used to convert the 3-PGA molecules into molecules of a three-carbon sugar, glyceraldehyde-3-phosphate (G3P). This stage gets its name because NADPH donates electrons to, or reduces, a three-carbon intermediate to make G3P.