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Question #47631

Difficulty: 8/10 | 🟢 Free

The Question

A plant physiologist is studying the photosynthetic rate of a $C_3$ plant (Bell pepper) and a $C_4$ plant (Sorghum) under varying atmospheric conditions. Based on Blackman's Law of Limiting Factors and the dual nature of RuBisCO, which of the following statements is INCORRECT?

Options

A.
In the $C_3$ plant, an artificially high $O_2:CO_2$ ratio induces a metabolic pathway that sequentially involves the chloroplast, peroxisome, and mitochondrion, leading to ATP consumption rather than synthesis.
B.
For the $C_3$ plant, if light and temperature are optimal, $CO_2$ acts as the major limiting factor, but its assimilation rate is directly antagonized by competitive binding of $O_2$ at the active site of RuBisCO.
C.
In the $C_4$ plant, an increase in atmospheric $O_2$ concentration induces photorespiration by triggering the oxygenase activity of RuBisCO located in the mesophyll cells.
D.
The $C_4$ plant avoids the systemic carbon loss seen in the $C_3$ plant because the decarboxylation of $C_4$ acids in the bundle sheath cells maintains a high intracellular $CO_2$ concentration, outcompeting $O_2$ .

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Regulatory_Failure

Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.

Concepts Behind This Question

RuBisCO|C3_vs_C4_Plants|CO2_Compensation_Point

Why This Question Is Tricky

Common Mistakes

Location Trap & Functional Misconception.

Students often fail to compartmentalize the enzymes of the C4 pathway (PEPcase in Mesophyll vs RuBisCO in Bundle Sheath).

Furthermore, they mistakenly assume that extreme atmospheric O2 can overcome the C4 CO2-concentrating mechanism, forgetting that PEPcase's strict specificity for CO2 acts as an absolute biochemical shield against photorespiration.

Quick Facts About This Question

Question Information

Subject	Biology
Chapter	Photosynthesis in Higher Plants - Class 11
Concept	Law of Limiting Factors
Difficulty	8
Cognitive Load	5
Target Solve Time	120 sec
Access	Free