Which one of these occurs durning the light reactions of photosynthesis?
a. carbon dioxide fixation
b. g3P production
c. NADPH production
d. reduction in carbon dioxide
What is your response to this question. After you have indicated, one of the teachers will be happy to make further comments.
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The correct answer is c. NADPH production.
To understand why, let's break down the options and explain each one:
a. Carbon dioxide fixation: Carbon dioxide fixation occurs during the Calvin cycle, which is part of the dark reactions or light-independent reactions of photosynthesis. In carbon dioxide fixation, carbon dioxide molecules react with a five-carbon compound called RuBP (ribulose-1,5-bisphosphate) using an enzyme called RuBisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase). This process does not occur during the light reactions.
b. G3P production: G3P (glyceraldehyde-3-phosphate) is a three-carbon molecule that is produced during the Calvin cycle as a result of carbon dioxide fixation. It is not directly associated with the light reactions.
c. NADPH production: NADPH (nicotinamide adenine dinucleotide phosphate) is an energy-carrying molecule that is crucial for the light reactions of photosynthesis. During the light reactions, sunlight is absorbed by chlorophyll molecules in the thylakoid membranes of chloroplasts. This energy is used to generate high-energy electrons, which are then transferred through a series of electron carriers, ultimately leading to the production of NADPH. NADPH is an important reducing agent that provides the necessary electrons for the Calvin cycle to fix carbon dioxide and produce glucose.
d. Reduction in carbon dioxide: Reduction refers to the gain of electrons or a decrease in the oxidation state of a molecule. While reduction does occur in the Calvin cycle when carbon dioxide is converted into G3P with the help of NADPH, it is not specific to the light reactions.
Therefore, the correct answer is c. NADPH production, as it is directly associated with the light reactions of photosynthesis.