Factors Affecting the Rate of Photosynthesis

Question 1

what are the factors that affect the rate of photosynthesis

Answer 1

1. carbon dioxide concentration
2. light intensity
3. temperature

Question 2

how does the concentration of carbon dioxide affect the rate of photosynthesis

Answer 2

• increase in CO2 concentration -> corresponding increase in rate of photosynthesis until the CO2 concentration is at its optimum
• rate of photosynthesis will decrease at very high carbon dioxide concentrations
• any factor that results in the closing of stomata will limit the amount of CO2 available, for photosynthesis, thereby reducing its rate

Question 3

how does light intensity affect the rate of photosynthesis

Answer 3

• at low light intensity => rate of photosynthesis is low
• as light intensity increases, rate of photosynthesis also increases up to the optimum for a particular environmental temperature
• any increase in light intensity beyond the optimum temperature does not result in an increase in the rate of photosynthesis

Question 4

how does temperature affect the rate of photosynthesis

Answer 4

• photosynthesis can take place in mesophytic plants between 10C and 35C (optimum is 25C)
• as temperature reaches 25, rate photosynthesis increases
• above 25, process slows down and can stop once the enzymes involved become denatured
• at low temperatures photosynthetic enzymes become inactive and the energy available for reactions is also decreased