B4: Limiting Factors/ The Rates of Photosynthesis

Question 1

What are the four main factors that affect the rate of photosynthesis

Answer 1

• temperature
• light intensity
• carbon dioxide concentration
• amount of chlorophyll

Question 2

How does temperature affect the rate of photosynthesis

Answer 2

Kinetic energy of particles are increased.

The rate decreases past 45 degrees as enzymes become denatured.

Question 3

What is a limiting factor?

Answer 3

An environmental factor which can restrict the rate of photosynthesis

Question 4

Explain how you can calculate the rate of photosynthesis by measuring oxygen production (P)

Answer 4

• set up a bubble potometer apparatus ( pondweed practical)
• oxygen gas produced causes the bubble in the capillary tube to move.
• The distance moved by the bubble is used to calculate the volume of oxygen produced

Question 5

How can farmers use their knowledge of limiting factors to increase their profits?

Answer 5

They can control : temperature
- light intensity( artificial light)
- CO2 concentration ( paraffin heaters)
leading to a greater yield

Question 6

State the law which describes the relationship between the distance of a light source from a plant and light intensity

Answer 6

Inverse square law- light intensity 1/ distance^2