B1.4.4 Interaction Of Limiting Factors

Question 1

How can you investigate the rate of photosynthesis?

Answer 1

Using pondweed, volume of oxygen given off is a measure of the rate of photosynthesis
This can be measured by simply counting the no. of bubbles produced

Question 2

What is the inverse square law?

Answer 2

When you double the distance from a light source, the light intensity falls by a factor of four.

Question 3

What is the formula for relative light intensity?

Answer 3

relative light intensity = 1/distance from light source^2

Question 4

On a cloudy day, what happens to the rate of photosynthesis?

Answer 4

It decreases as the light intensity decreases

Question 5

What is the limiting factor on a cold sunny winters day?

Answer 5

The temperature

Question 6

Why do commercial growers increase levels of carbon dioxide in their greenhouses?

Answer 6

Carbon dioxide concentration in the atmosphere is low, and is often a limiting factor to photosynthesis.
Increasing the level in greenhouses makes sure there is enough for the plants to continue growing quickly.