C4 Plants and Photorespiration Prevention — NEET Biology
✅ Asked in NEET 2016The process which makes major difference between C₃ and C₄ plants is: (NEET 2016 Phase 2)
The process which makes major difference between C₃ and C₄ plants is: (NEET 2016 Phase 2)
Q33. A plant in your garden avoids photorespiratory losses, has improved water use efficiency, shows high rates of photosynthesis at high temperatures and has improved efficiency of nitrogen utilisation. In which of the following physiological groups would you assign this plant? (NEET 2016 Phase 1)
Answer & NCERT explanation
Correct answer: C — Photorespiration
Photorespiration is the major differentiating process between C3 and C4 plants. In C3 plants, photorespiration occurs significantly due to RuBisCO's oxygenase activity, leading to loss of fixed carbon. C4 plants have evolved mechanisms to minimize photorespiration by concentrating CO2 around RuBisCO in bundle sheath cells. Glycolysis, Calvin cycle, and respiration occur in both plant types with similar mechanisms.
Read more NCERT concept on the PYQ
In C₄ plants photorespiration does not occur. This is because they have a mechanism that increases the concentration of CO₂ at the enzyme site. This takes place when the C₄ acid from the mesophyll is broken down in the bundle sheath cells to release CO₂ – this results in increasing the intracellular concentration of CO₂. In turn, this ensures that the RuBisCO functions as a carboxylase minimising the oxygenase activity.
C4 plants avoid photorespiration by concentrating CO₂ inside bundle sheath cells, forcing RuBisCO to act as a carboxylase instead of an oxygenase. Students often confuse this with C3 plants and don't understand that the C4 acid breakdown in bundle sheaths is the key mechanism. The common mistake is thinking photorespiration is completely absent in all plants or that it's simply avoided by CO₂ availability in the atmosphere. Remember: C4 plants use a spatial separation strategy (mesophyll → bundle sheath) to maintain high intracellular CO₂, ensuring RuBisCO performs carboxylation, not oxygenation. This distinction between C3 and C4 pathways is fundamental to understanding plant adaptation to different environments.
What does NCERT say about C plants photorespiration does?
Has this concept appeared in NEET?
Which chapter is this from?
Through deep analysis of NEET and NTA, 88 of 90 questions from the NEET 2026 paper were matched straight from the MedicNEET Biology question bank.
88/90MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.