Limiting Factors

Question 1

How can chlorophyll be a limiting factor?

Answer 1

Less Magnesium ions, yellow spots on leaves meaning they haven’t photosynthesised

This condition is called chlorosis

Tobacco mosaic virus - mottled mosaic of yellow patches where chloroplast has been destroyed

Variegated leaves - lead is not entirely green, naturally photosynthesising slower than non variegated leaves

Question 2

Rate of photosynthesis and light intensity graph

Answer 2

Increases until reaching optimum, it then remains the same

Question 3

Rate of photosynthesis and co2 graph

Answer 3

Continuous increase (co2 is the limiting factor) until reaches optimum, then stays the same

Question 4

Rate of photosynthesis and temperature graph

Answer 4

Increases to an optimum because higher kinetic energy means more collisions and then it falls as the enzymes denatured until reaching zero

Question 5

What’s the optimum percentage of co2 and temperature?

Answer 5

0.4% and 30°C

Question 6

How can you increase percentage of Co2?

Answer 6

With a paraffin heater

Question 7

Benefits of using greenhouse?

Answer 7

Decreases risks of diseases
Decreased competition due to weed
Fertiliser can be added