Limiting Factors

What are the requirements for photosynthesis?

Photosynthetic pigments carbon dioxide water light and suitable temperature

What is the role of photosynthetic pigments?

Absorb light energy

What is the role of carbon dioxide in photosynthesis?

Provides carbon to make glucose

What is the role of water in photosynthesis?

Provides electrons and protons

What is the role of light in photosynthesis?

Provides energy for photolysis ATP production and reduction of NADP

What is the role of temperature in photosynthesis?

Provides kinetic energy for reactions

What is a limiting factor?

A requirement that is in shortest supply

What happens when a limiting factor increases?

The rate of photosynthesis increases

What are the three main limiting factors of photosynthesis?

Light intensity carbon dioxide concentration and temperature

What happens at low light intensity?

The light dependent reaction is limited

Why does low light intensity reduce photosynthesis?

Less ATP and reduced NADP are produced

What happens as light intensity increases?

The rate of photosynthesis increases

Why does photosynthesis plateau at very high light intensity?

Another factor becomes limiting

What is the light compensation point?

The point where photosynthesis and respiration have equal gas exchange

What happens at the light compensation point?

Oxygen production equals oxygen uptake and carbon dioxide uptake equals carbon dioxide production

What happens at low carbon dioxide concentration?

The light independent reaction is limited

Why does low carbon dioxide reduce photosynthesis?

Less carbon dioxide is fixed

What happens as carbon dioxide concentration increases?

The rate of photosynthesis increases

Why does photosynthesis plateau at high carbon dioxide concentration?

Another factor becomes limiting

What is the saturation point?

The point where the factor being measured is no longer limiting

What happens at low temperature?

Enzyme controlled reactions slow down

Why does low temperature reduce photosynthesis?

There is less kinetic energy for enzyme catalysed reactions

What happens as temperature increases?

The rate of photosynthesis increases up to an optimum

What happens at very high temperature?

Enzymes denature and the rate of photosynthesis decreases

Which enzyme catalyses carbon fixation?

Rubisco

How does temperature affect rubisco controlled reactions?

Low temperature slows them and high temperature can denature enzymes