Exam style questions - photosynthesis limiting factors

explain why a decrease in light intensity limits the Calvin cycle ( LIR) 2

Less GP, reduce TP, Less RuBP regenerated in the Calvin cycle .

why temperature is a limiting factor of photosynthesis ?

Temperature is a limiting factor because :

If temp too high : Rubisco will denature = no CO2 fixation

If temp too low : Rubisco’s activity will slow down

In LDR if temp too high : protein in LDR such as H+ pump and ATP synthase can be denatured = less ATP produced

when temperature increases above 30*c , O2 competes with CO2 for Rubisco’s active site. What effect will this have on the Calvin cycle ?u

If temp at 30*c , O2 competes with CO2 for Rubisco = ;less CO2 fixation → Build up of RuBP → Less CO2 reduction , less GP reduced TP, less RuBP regenerated. 

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