Class 11 Biology - Chapter Photosynthesis in Higher Plants NCERT Solutions | RuBisCo is an enzyme that acts both as a

Welcome to the NCERT Solutions for Class 11th Biology - Chapter Photosynthesis in Higher Plants. This page offers a step-by-step solution to the specific question from Exercise 1, Question 4: rubisco is an enzyme that acts both as a carboxyla....
Question 4

RuBisCo is an enzyme that acts both as a carboxylase and oxygenase. Why do you think RuBisCo carries out more carboxylation in C4plants?

Answer

The enzyme RuBisCo is absent from the mesophyll cells of C4 plants. It is present in the bundle-sheath cells surrounding the vascular bundles. In C4 plants, the Calvin cycle occurs in the bundle-sheath cells. The primary CO2 acceptor in the mesophyll cells is phosphoenol pyruvate – a three-carbon compound. It is converted into the four-carbon compound oxaloacetic acid (OAA). OAA is further converted into malic acid. Malic acid is transported to the bundle-sheath cells, where it undergoes decarboxylation and CO2fixation occurs by the Calvin cycle. This prevents the enzyme RuBisCo from acting as an oxygenase.

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