Limiting Factors

Question 1

give the 3 limiting factors of photosynthesis?

Answer 1

• light intensity
• Carbon dioxide concentration
• temperature

Question 2

how does light intensity affect the rate of photosynthesis?

Answer 2

• the higher the light intensity, the more energy there is for the light dependent reaction
• faster the rate of photosynthesis
• light needs to be the right wavelengths
• so they look green because they reflect green light
• they absorb red and blue
• different pigments absorbs different wavelengths

Question 3

how does carbon dioxide affect the rate of photosynthesis?

Answer 3

• carbon dioxide needed for the light independent reaction
• carbon dioxide is continuously the limiting factor (day twice)
• carbon dioxide is about 0.04% of the atmosphere
• optimum carbon dioxide concentration is 0.4%
• above 0.4% - carbon dioxide has a negative effect on the rate of photosynthesis

Question 4

how does temperature affect the rate of photosynthesis?

Answer 4

• photosynthesis is controlled by enzymes
• if you increase temperature, you increase the rate of reaction up to the optimum temperature
• beyond the optimum temperature, the temperature decreases
• high temp can cause the stomata to close -> carbon dioxide decreases
  therefore decreases the calvin cycle

Question 5

how could someone increase light intensity?

Answer 5

• use lighting at night (correct wavelength)
• absorbs light to pass in

Question 6

how could someone increase carbon dioxide?

Answer 6

• burns fossil fuel in a greenhouse
• increase carbon dioxide concentration
  e.g. propane

Question 7

how could someone increase temperature?

Answer 7

• burner increases temperature
  greenhouse traps warm air
• heating/ cooling to maintain optimum temperature (thermostat)