Question

In $C - 4$ plants, the primary $C{O_2}$ acceptor is ?

Answer 1

Hint: \[C - 4\] photosynthesis is a carbon concentration mechanism used by some plants to increase photosynthetic carbon fixation ability. Most \[C - 4\] plants' leaves have a Kranz Type anatomy composed of bundle sheath and mesophyll cells. Rubisco is only found in internalised bundle sheath cells or internalised chloroplasts in \[C - 4\] leaves, where it protects against atmospheric \[{O_2}\] and limits the oxygenase function of this enzyme.

Complete explanation:
The \[3\]-carbon molecule phosphonyl pyruvate is the main \[C{O_2}\] acceptor in \[C - 4\]plants (PEP). The first step in the \[C - 4\] pathway is the carboxylation of PEP, which results in the formation of oxaloacetic acid. It is eventually converted into malic acid, a \[4 - C\]compound. They are later moved from mesophyll to bundle sheath cells. In this step, OAA is broken down to produce carbon dioxide and a \[3 - C\] molecule. The \[C{O_2}\]generated is used in the Calvin cycle, while the \[3 - C\] molecule is transferred back to mesophyll cells for PEP regeneration.

Note:
Thus, it is stated that the \[C - 4\] pathway begins with a three-carbon molecule known as phosphoenolpyruvate (PEP). This is the main \[C{O_2}\] acceptor, and carboxylation occurs with the aid of an enzyme known as PEP carboxylase. They produce oxaloacetic acid, a \[4 - C\] molecule (OAA).

Additional knowledge:
Just about \[3\% \] of all vascular plants use the \[C4\] pathway. The plants get their name from the \[4\]-carbon compound oxaloacetate, which is formed during the pathway.
\[C4\] plants are extremely active in hot and dry climates, producing a large amount of energy. \[C4\] plants that we commonly eat include pineapple, corn, sugar cane, and so on.