• Properties of Rubisco:
• Substrate Promiscuity: Rubisco catalyzes both carboxylation and oxygenation of ribulose 1,5-bisphosphate (RuBP).
• Oxygenase Reaction: $\text{RuBP} + \text{O}_2 \rightarrow \text{3-PGA} + \text{2-phosphoglycolate}$.
• Kinetic Affinities: Apparent $K_m$ for $\text{CO}_2$ is $\approx 9\ \mu\text{M}$, whereas $K_m$ for $\text{O}_2$ is $\approx 350\ \mu\text{M}$.
• Photorespiratory Loss: Photorespiration consumes ATP and reducing equivalents without net carbon fixation, dissipating up to 30–50% of fixed carbon in $C_3$ crop canopies.
• Conclusion: Statements (A), (B), (C), and (D) are all correct.

Correct option: (3) (A), (B), (C) and (D).

• Statement (I) is True: Starch (insoluble glucan polymer) serves as the primary long-term storage carbohydrate, while sucrose (water-soluble disaccharide) serves as the primary transport and short-term storage carbohydrate in vascular plants.
• Statement (II) is False: Starch is synthesized and stored in plastids—transient starch in photosynthetic chloroplasts during the day, and storage starch in non-photosynthetic amyloplasts—never in mitochondria.
• Conclusion: Statement (I) is true but Statement (II) is false.

Correct option: (3) Statement (I) is true but Statement (II) is false.