Question

Sugarcane shows high efficiency of $C{O}_2$ fixation because it performs

• A. Calvin cycle
• B. EMP pathway
• C. Hatch and Slack pathway
• D. TCA cycle

Answer 1

Answer: (C)

Hatch and Slack pathway

Most of the plants that are adapted to dry tropical regions have the $C_4$ pathway. These plants are called $C_4$ plants. Sugarcane, Maize, Sorghum, Corn, etc., are the examples of these plants. Sugarcane is also a $C_4$ plant, so it has high efficiency of $C{O}_2$ fixation because it performs Hatch-Slack pathway. It is also known as $C_4$ pathway. Carbon dioxide fixation is done in this pathway. The primary $C{O}_2$ acceptor is a three-carbon molecule phosphoenol pyruvate (PEP) and it is present in mesophyll cells. The enzyme that catalyzes this $C{O}_2$ fixation is PEP carboxylase or PEPcase. The mesophyll cells of $C_4$ plants lack the enzyme RuBisCO. The 4-carbon oxaloacetic acid (OAA) is formed in the mesophyll cells which is further converted into the malic acid or aspartic acid and then transported into bundle sheath cells. In the bundle sheath cells, these $C_4$ acids are broken down to release $C{O}_2$ and a three-carbon molecule.