Question

The source of hydrogen for carbon assimilation is derived from
A. $FAD{H_2}$
B. CHlorophyll
C. RuBP
D. NADPH

Answer 1

Hint: Plants do photosynthesis at a very slow rate in the night. They need sunlight to make their food. Conversion of sunlight to chemical energy needs electrons, ATP, NADPH, etc. They run through a cascade to produce CO2, water, and energy.

Step by step answer:Carbon fixation is another name for carbon assimilation. The process in which the carbon source is used to form the major organic end products is the carbon fixation process. Photosynthesis is an example of this process. In the literal sense, carbon fixation means to fix carbon at a place. In this, the inorganic compounds are converted into organic compounds. In photosynthesis, light-independent reactions do the carbon fixation via the Calvin cycle. Photosynthesis is the process of making plant food in the presence of sunlight. This process occurs in the chlorophyll in the plastids. The photosynthesis process is done by absorbing the sunlight and converting it into chemical energy. The process needs light to occur. It has two photosystems- light reaction and dark reaction. Both processes occur in the day time. Plant do photosynthesis at a good rate in the day only. So the light reaction will produce NADPH, ATP which will be used by the dark reaction. In the Calvin cycle, 9 ATP and 6 NADPH molecules are formed.
Option A: $FAD{H_2}$: This is a side energy molecule formed but the primary energy sources are ATP and NADPH.
Option B: Chlorophyll: It is the place where the whole process occurs in the plants.
Option C: RuBP: carbon dioxide binds with RuBP sugar with the help of Rubisco to split the 6C compound into a 3C compound.
Option D: NADPH: Energy provided to pursue this whole process is given by ATP and NADPH, these are the molecules having energy captured from the sunlight.
Hence, the answer is option D: NADPH

Note: This reaction is also called the C3 cycle or the reductive pentose phosphate process. The plants carrying out the Calvin cycle are called C3 plants. The Calvin cycle occurs in three steps- fixation, reduction, and regeneration.