A process that makes important difference between $C_3$ and $C_4$ plants is
- Glycolysis
- Calvin cycle
- Photorespiration
- Respiration
The Correct Option is C
Solution and Explanation
Photorespiration
Photorespiration is the light-dependent process of oxygenation of ribulose bisphosphate (RuBP) and the release of carbon dioxide by the photosynthetic organs of a plant. This process occurs in the chloroplast and involves the participation of peroxisomes and mitochondria to complete the cycle.
Key Points of Photorespiration:
- It is a light-dependent process where oxygen is consumed and carbon dioxide is released.
- Photorespiration occurs in the chloroplast, peroxisomes, and mitochondria.
- This process is important in distinguishing C3 plants from C4 plants, as it is absent in C4 plants.
Conclusion:
In C3 plants, photorespiration is a common process, whereas C4 plants have adapted mechanisms to minimize or eliminate photorespiration, making them more efficient in hot and dry climates.
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Concepts Used:
Photorespiration
Photorespiration is a wasteful process in plants in which plants intake oxygen, and sunlight and release carbon dioxide and no glucose is formed. Photorespiration generally takes place when the concentration of oxygen in the leaves is very high and that of carbon dioxide is very low.
In Calvin cycle carbon dioxide fixation does not take place . Hence, instead of carbon dioxide oxygen reacts with RuBP.
Photorespiration in C3 and C4 Plants:
- C4 plants do not undergo photorespiration due to their special mechanism to increase the CO2 level for enzyme binding.
- In Hatch and Slack Pathway, C4 acid and oxaloacetic acid breaks down to release CO2.
- This ensures a high concentration of intercellular CO2.
- Thus, in C4 plants, RuBisCO is more active as a carboxylase enzyme rather than as an oxygenase.
- This is why C4 plants have better productivity.