The oxygenation activity of RuBisCo enzyme in photorespiration leads t...
Photorespiration is the light dependent process. At high temperature, RuBP carboxylase functions as oxygenase and instead of fixing carbon dioxide (C3 cycle), oxidises ribulose 1, 5-biphosphate to produce a 3-carbon phosphoglyceric acid and a 2-carbon phosphoglycolate.
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The oxygenation activity of RuBisCo enzyme in photorespiration leads t...
Explanation:
The oxygenation activity of the enzyme RuBisCo in photorespiration leads to the formation of one molecule of a 3-C compound. This compound is called phosphoglycolate.
Photorespiration:
Photorespiration is a process that occurs in plants when there is a high concentration of oxygen and low concentration of carbon dioxide in the leaf cells. This can happen in conditions such as high temperatures or when the stomata are closed, limiting the entry of carbon dioxide into the leaves.
RuBisCo Enzyme:
RuBisCo (Ribulose-1,5-bisphosphate carboxylase/oxygenase) is an enzyme involved in the first step of the Calvin cycle, which is the process of carbon fixation in photosynthesis. It catalyzes the reaction between carbon dioxide (CO2) and ribulose-1,5-bisphosphate (RuBP) to form two molecules of 3-phosphoglycerate (3-PGA).
Problem with RuBisCo:
However, RuBisCo has a tendency to also react with oxygen instead of carbon dioxide. This is known as oxygenation activity and leads to the formation of one molecule of a 3-C compound called phosphoglycolate and one molecule of a 2-C compound called phosphoglycolate.
Formation of 3-C compound:
In the oxygenation reaction, RuBisCo adds one molecule of oxygen (O2) to RuBP instead of carbon dioxide. This results in the formation of one molecule of phosphoglycolate, which has three carbon atoms.
Importance of phosphoglycolate:
Phosphoglycolate is a metabolic product that cannot be directly used by the plant for further carbon fixation. It needs to be converted into a usable form through a series of reactions known as the photorespiratory pathway. This pathway involves the conversion of phosphoglycolate into a 3-C compound called phosphoglycolate, which can then reenter the Calvin cycle for further carbon fixation.
Conclusion:
In photorespiration, the oxygenation activity of RuBisCo enzyme leads to the formation of one molecule of a 3-C compound called phosphoglycolate. This compound is then converted into a usable form through the photorespiratory pathway.
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