5.1 Photosynthesis - Limiting Factors (GCSE Recap)

Question 1

what are the 3 factors which can limit photosynthesis?

Answer 1

light intensity, temperature and carbon dioxide concentration

Question 2

draw the graph showing how light intensity affects the rate of photosynthesis

Answer 2

(check against notes)

Question 3

draw the graph showing how temperature affects the rate of photosynthesis

Answer 3

(check against notes)

Question 4

draw the graph showing how carbon dioxide concentration affects the rate of photosynthesis

Answer 4

(check against notes)

Question 5

how does light intensity affect the rate of photosynthesis? (2 points)

Answer 5

1) Increasing the light intensity causes photosynthesis to occur at a faster rate due to light energy being required for the endothermic reaction
2) Rate plateaus (remains constant) as another factor is now limiting the rate

Question 6

how does temperature affect the rate of photosynthesis? (3 points)

Answer 6

1) Increasing the temperature increases the kinetic energy, leading to a faster rate as there are more collisions of reactants with enzymes
2) Fastest rate at optimum temperature
3) Active site loses its shape as the enzyme becomes denatured, and so rate decreases as less enzyme-substrate complexes are formed

Question 7

how does carbon dioxide concentration affect the rate of photosynthesis? (2 points)

Answer 7

1) Increasing the carbon dioxide concentration will increase the rate of photosynthesis due to it being a reactant
2) Rate plateaus as another factor is now limiting the rate