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In a hypothetical experiment, a scientist genetically modifies a C4 plant to lack PEP carboxylase. Which of the following would be the MOST likely outcome under normal atmospheric conditions?
The plant would switch to CAM photosynthesis.
The plant would exhibit significantly reduced CO2 fixation and increased photorespiration.
CO2 fixation would remain unchanged, but the plant would require more water.
The plant would grow more efficiently due to reduced energy expenditure in the C4 pathway.
A mutation in a plant affects the enzyme responsible for converting glyceraldehyde-3-phosphate (G3P) to dihydroxyacetone phosphate (DHAP). Which of the following is the MOST likely direct consequence of this mutation on the Calvin cycle?
Complete cessation of the Calvin cycle
Accumulation of 3-PGA
Increased RuBisCO activity
Reduced export of triose phosphates from the chloroplast and impaired sucrose synthesis
A researcher exposes two genetically identical plants to different light intensities. Plant A receives high intensity monochromatic red light, while Plant B receives low intensity polychromatic light. Assuming all other factors are optimal, which statement is MOST likely true regarding the quantum yield of photosystem II (ΦPSII)?
Plant A will likely have a higher ΦPSII than Plant B.
Plant B will likely have a higher ΦPSII than Plant A.
The ΦPSII will be approximately equal in both plants.
The ΦPSII will be zero in both plants due to the different light conditions.
A C4 plant and a CAM plant are grown under identical environmental conditions. Which statement BEST describes their relative water use efficiency (WUE) and photosynthetic rates under prolonged high light intensity and high temperature?
The C4 plant will have both higher WUE and a higher photosynthetic rate than the CAM plant.
The CAM plant will have higher WUE than the C4 plant, but the C4 plant will have a higher photosynthetic rate.
The C4 plant will have higher WUE than the CAM plant, but the CAM plant will have a higher photosynthetic rate.
The CAM plant will have both higher WUE and a higher photosynthetic rate than the C4 plant.
Which of the following statements about the light-independent reactions of photosynthesis is INCORRECT?
CO2 is fixed
ATP and NADPH are required
Glucose is the immediate product
The reactions occur in the stroma
A researcher observes a plant exhibiting high photosynthetic rates even under high light intensity and temperature conditions. Which of the following is the LEAST likely explanation for this observation?
The plant utilizes a C4 photosynthetic pathway.
The plant exhibits low photorespiration rates.
The plant has an extensive root system.
The plant effectively manages water loss.
Select the incorrect statement w.r.t. Photosystem II.
It is located in the thylakoid membrane.
Water is the ultimate electron donor.
Its reaction center chlorophyll a is P680.
It produces NADPH directly.
Select the incorrect one about photosystem I
Found in stroma lamellae
Involves in non cyclic photophosphorylation
Has chl a which shows maximum absorption at 700 nm
Is not involved in cyclic photophosphorylation
Which of these ensures that the RUBISCO functions as a carboxylase minimising the oxygenase activity at the site of fixation in plants?
Agranal chloroplast in bundle sheath cells
Special type of leaf anatomy
Breaking down of malic acid in bundle sheath cells
Much greater affinity of rubisco for than for in bundle sheath cells
