In sugarcane plant,${}^{14}\mathrm{CO}_2$ is fixed in malic acid in which the enzyme that fixes ${\mathrm{CO}}_2$ is
1. Ribulose biphosphate carboxylase
2. Phosphoenol pyruvic acid carboxylase
3. Ribulose phosphate kinase
4. Fructose phosphatase

Identify the incorrect statement regarding the enzyme PEP carboxylase:
1. PEP carboxylase has a lower Km for bicarbonate ions, hence, higher affinity — than RuBisCO.
2. ${\mathrm{O}}_2$ is a very poor substrate for this enzyme.
3. It plays an important role in ${\mathrm{C}}_4$ cycle but not in CAM plants.
4. PEP carboxylase is also significant in non-photosynthetic metabolic pathways.

The first stable product of CO₂ fixation in sorghum is:

Current availability of carbon dioxide is limiting to C3 plants . This means that:
1. At low light intensity, C₃ plants respond to high CO₂ concentrations
2. Growing plants like tomatoes in carbon dioxide-rich environment is unlikely to increase yield
3. They show saturation in the rates of photosynthesis at carbon dioxide concentration higher than the current level
4. They have better water use efficiency and thus, adapted to warm tropical climates

Photosynthesis in ${\mathrm{C}}_4$ plants is relatively less limited by atmospheric ${\mathrm{CO}}_2$ levels because
1. The primary fixation of ${\mathrm{CO}}_2$ is mediated via PEP carboxylase.
2. Effective pumping of ${\mathrm{CO}}_2$ into bundle sheath cells.
3. Four carbon acids are the primary initial ${\mathrm{CO}}_2$ fixation products.
4. RuBisCO in ${\mathrm{C}}_4$ plants has higher affinity for ${\mathrm{CO}}_{2.}$

Identify the incorrect match:

Which of the following statements is incorrect?
1. RuBisCO is a bifunctional enzyme
2. In C₄ plants, the site of RuBisCO activity is mesophyll cell
3. The substrate molecule for RuBisCO activity is a 5-carbon compound
4. RuBisCO action requires ATP and NADPH