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InterviewSolution
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With reference to factors affecting the rate of photosynthesis, which of the following statements is not correct ?A. Light saturation for `CO_(2)`-fixation occurs at 10% of full sunlightB. increasing atmospheric `CO_(2)` concentration upto 0.05% can enchance `CO_2`-fixation rateC. `C_(3)`-plants respond to higher temperature with enchanced photosynthesis, while `C_(4)`-plants have much lower temperature optimumD. Tomato is greenhouse crop, which can be grown in `CO_(2)` enriched atmosphere for higher yield. |
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Answer» Correct Answer - C In `C_(4)`-plants, the initial fixation of `CO_(2)` occurs in mesophyll cells. The primary acceptor of `CO_(2)` in phosphoenol Pyruvate (PEP). It combines with `CO_(2)` in the presence of enzyme PEP carboxylase to form the first stable product, i.e. Oxalo acetic Acid (OAA). Where as `C_(3)`-plants lack `PEP_("carboxylase")` enzyme. The possess RuBisCO enzyme. This enzyme can work as both carboxylase (fixation of `CO_(2)`) and oxygenase (fixation of `O_2`). RuBisCO has a much greater affinity for `CO_(2)` than for `O_(2)` and the binding is competitive. At higher temperature, its affinity for `CO_(2)` decrease and it works as oxygenase. Therefore, at higher temperature photosynthesis decrease in `C_(3)`-plants, while in `C_(4)`-plants it increases. |
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