Question

Calvin cycle operates in chloroplasts. Where does Hatch-Slack pathway occur

• A. Mitochondria
• B. Golgi bodies
• C. Chloroplasts
• D. Cytoplasm.

Answer 1

The correct option is C Chloroplasts

Hatch-Slack pathway is a cyclic process. It occurs in chloroplasts. It was discovered by two Australian scientists Hatch and Slack. It is also known as $C_4$ pathway because it is found in $C_4$ plants. 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 catalyses 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 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.