Fri February 11, 2011 By: Subhash Chand

HI MA'M Q1:why does oxygen bubbles increases on adding baking soda to beaker containing water and hydrila in it ? Q2:how the CO2 splits up to carbohydrates in absence of light energy (or sunlight) ?

Expert Reply
Tue February 15, 2011
Dear student,
1) This is because soda bicarbonate acts as a source of carbon dioxide.
2) During photosynthesis, two general kinds of reactions are involved i.e the light reactions and the dark reactions.
Light reactions, as their name suggests, can take place only in the presence of sunlight. In these reactions, light energy is used to generate certain kinds of energy-rich compounds. These compounds do not themselves become part of the final carbohydrate product. Instead, they are used to "carry" energy from one compound to another in the process of photosynthesis.

The dark reactions are able to take place in the absence of sunlight, although they often occur during the daylight hours. During the dark reactions, the energy-rich compounds produced in the light reactions generate the compounds from which carbohydrates are eventually produced.

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