Component 1.2 - Limiting Factors & Mineral Nutrition

Question 1

Describe relationship between CO2 concentration and rate of photosynthesis

Answer 1

As carbon dioxide increases the rate of photosynthesis increases (it is a limiting factor)
Graph begins to plateau as increased CO2 concentration no longer has any effect on rate (no longer limiting factor)
Stomata will close when CO2 is too high and rate will decrease

Question 2

Describe relationship between light intensity and rate of photosynthesis

Answer 2

As light intensity increases, light dependent reactions and overall rate of photosynthesis increases
At a certain intensity the reactions of the light dependent reaction are at their maximum rate (light intensity no longer limiting factor)
If the light intensity is any higher the rate of photosynthesis can decrease because the photosynthetic pigments become damaged

Question 3

What is a light compensation point?

Answer 3

The light intensity at which a plant has no net gas exchange as the volume of gases used and produced in respiration and photosynthesis are equal

Question 4

Light compensation points: sun vs shaded plants

Answer 4

They occur at lower light intensities for shade plants than for sun plants, so they can grow in more shaded habitat.

Question 5

What is magnesium used for in plants?

Answer 5

In chlorophyll

Question 6

What happens when a plant has a nitrogen deficiency?

Answer 6

Reduced growth

Question 7

What is nitrogen used for in plants?

Answer 7

Synthesis of proteins, nucleic acids, chlorophyll