Question

ATP and NADPH produced in light reaction by
the movement of electrons in ETC are used
immediately for
(a) oxidation of carbohydrate
(b) synthesis of sugar
c) reduction of carbon dioxide
(0) Both (b) and ic)​

Answer 1

Answer:

(d). Both (b) and (c)

Explanation:

The ATP and NADPH produced in the light-dependent reaction move to the stroma and contribute to the light-independent reaction (dark reaction/ Calvin cycle). These stored chemical energies aid the fixation of “C” from CO2 into the molecules that are used to build glucose (sugar molecule).

1. Carbon fixation - An enzyme present in the stroma called RuBisCo combines RubP (five-carbon molecule, ribulose biphosphate) to CO2 molecule which creates a six-carbon molecule. Later, this molecule will be broken down into two 3-phosphoglycerate molecules (three-carbon molecules).
2. Reduction - A hydrogen atom is transferred to each 3-phosphoglycerate molecule by the ATP and NADPH to create two molecules of G3P (glyceraldehyde-3-phosphate). These two G3P molecules are used to build a molecule of glucose.

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Answer 2

Answer:

The correct option is (d):both(b) and(c)

Explanation:

ATP and NADPH produced in the light reaction by the movement of electrons in ETC are used for the synthesis of sugar and oxidation of carbohydrates

• In Calvin cycle or dark reaction the ATP and NADPH are used up to produce sugar molecule
• Calvin cycle has 3 steps: Carboxylation, Reduction and Regeneration
• Carboxylation: In this step,5 carbon RuBP molecule is converted to 3 phosphoglycerate (3PGA) molecule in presence of Carbon dioxide,water and RuBP carboxylase enzyme; crucial step of the Calvin cycle
• Reduction:This is the step where two ATP and two NADPH are used per cycle to produce glucose molecule from 3 PGA molecule by reduction; this step is done 6 times to produce one glucose molecule
• Regeneration: This step requires one ATP to generate the RuBP molecules

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