Photosynthesis in Detail
Photosynthesis is the process by which plants, algae, and cyanobacteria convert light energy into chemical energy (glucose). It is the foundation of most food chains on Earth.
What You Need to Know
Key Concept Diagram
Photosynthesis equation: 6CO2 + 6H2O + light energy → C6H12O6 + 6O2
Chlorophyll in chloroplasts absorbs light energy (mainly red and blue wavelengths)
The two stages are the light-dependent reactions (producing ATP and O2) and the light-independent reactions (Calvin cycle, producing glucose)
Rate of photosynthesis is affected by light intensity, CO2 concentration, temperature, and water availability
Key Vocabulary
Chlorophyll
The green pigment in chloroplasts that absorbs light energy for photosynthesis
Chloroplast
The organelle in plant cells where photosynthesis takes place
Calvin cycle
The light-independent stage of photosynthesis where CO2 is fixed into glucose
Limiting factor
A factor that limits the rate of photosynthesis when it is in short supply
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
A plant is kept in the dark for several days. What happens to its rate of photosynthesis?
Question 2
Which gas is released as a by-product of photosynthesis?
Question 3
A plant is given plenty of light and water but photosynthesis remains slow. What is most likely limiting it?
Key Concepts Summary
- ●Photosynthesis equation: 6CO2 + 6H2O + light energy → C6H12O6 + 6O2
- ●Chlorophyll in chloroplasts absorbs light energy (mainly red and blue wavelengths)
- ●The two stages are the light-dependent reactions (producing ATP and O2) and the light-independent reactions (Calvin cycle, producing glucose)
- ●Rate of photosynthesis is affected by light intensity, CO2 concentration, temperature, and water availability