Limiting Factors

• What are the limiting factors of photosynthesis and what stage of photosynthesis will they effect?

  1. Low carbon dioxide concentration - affects the light independent reaction.
  2. Low light intensity - affects both stages.
  3. Low/High temperature - affects the enzymes of the light independent reaction.
• With limited light how is the light dependent stage of photosynthesis impacted?

  Fewer electrons are released and lost from the chlorophyll, resulting in less photoionisation. Less photolysis will occur so less dissociation occurs and fewer electrons are released by water.
• With limited light how is the light independent stage of photosynthesis impacted?

  No ATP or NADPH is produced in the light dependent stage so glycerate 3-phosphate cannot be reduced to triose phosphate, leading to a build up of glycerate 3-phosphate.
• With low temperatures how is photosynthesis impacted?

  There is less kinetic energy and so fewer enzyme-substrate complexes form through the enzyme rubisco.
• With high temperatures how is photosynthesis impacted?

  Enzymes are denatured (rubisco) and so enzyme-substrate complexes cannot form. This leads to a decrease in the rate of the light independent stage of photosynthesis.
• With limited carbon dioxide how is photosynthesis impacted?

  The rate of the Calvin cycle decreases as less ribulose bisphosphate is converted into glycerate 3-phosphate, this leads to the accumulation of ribulose bisphosphate and a decrease in glycerate 3-phosphate.