Limiting factors on photosynthesis

Recap ~ where is Rubisco found in photosynthesis ?

Rubisco is found in the storm of the chloroplast

Recap ~ How are chloroplast adapted to maximise the light independent reaction ?

Large SA of thylakoid membrane so more ATP and NADPH

Stroma contains DNA / ribosomes to synthesis enzymes / rubisco

Stroma contains enzyme / rubisco requires for LIR

Stroma surrounds grand / thylakoid so products of the LDR can diffuses into stroma for LIR.

what is a limiting factor ?

Any essential factor or condition that is in short supply and restricts the rate of a physiological process. 

what are the limiting factors in photosynthesis ? 

Light intensity , temperature , con.c of CO2 and Chlorophyll 

Draw a graph of temperature 

Draw a graph of light intensity

Draw a graph of concentration of CO2

Explain why temperature is an important factor of photosynthesis 

The enzymes catalysing the reactions of the light independent stage and some of the light dependent stage are affected by temperature.

Photosynthesis is affected by temperature because many of its reactions are enzyme-controlled. As temperature rises, the rate of photosynthesis increases until it reaches an optimum, after which enzymes denature and the rate decreases. The light-dependent reactions are less influenced by temperature since they rely on light energy, but the Calvin cycle depends strongly on temperature-sensitive enzymes like rubisco. Other factors, such as stomatal closure at high temperatures (limiting CO₂ uptake) and changes in membrane permeability that disrupt the proton gradient, can also reduce photosynthesis under extreme conditions.

Explain why light is an important factor of photosynthesis 

As light intensity increases, the rate of photosynthesis rises because more ATP and reduced NADP are produced in the light-dependent reactions, driving the Calvin cycle faster. However, once light intensity is no longer limiting, the rate plateaus and another factor, such as temperature or carbon dioxide concentration, becomes limiting.

Explain why CO2 is an important factor of photosynthesis 

As carbon dioxide concentration increases, the rate of photosynthesis rises because CO₂ is needed for carbon fixation in the Calvin cycle. However, once CO₂ is no longer limiting, the rate plateaus and other factors such as light intensity or temperature become limiting.

CO2 is fixed with RuBP, using the enzyme Rubisco in the initial reaction of the light independent reaction.