Unit 3 Photosynthesis Flashcards
What are the stages of photosynthesis?
- Light reactions
- Carbon fixation
Describe light reactions.
The light energy from the sun is trapped by chlorophyll in the chloroplasts and is converted into chemical energy which is used to generate ATP.
Water is split to produce hydrogen and oxygen. Oxygen diffuses from the cell.
Describe carbon fixation.
A series of enzyme controlled reactions, which use hydrogen and ATP (produced by the light reactions) with carbon dioxide to produce sugar.
Summarise the process of photosynthesis.
Carbon dioxide + water —>light energy—> sugar + oxygen
What is chemical energy in sugar used for?
The chemical energy in sugar is available for respiration or the sugar can be converted into other substances such as starch (storage) and cellulose (structural)
What are some limiting factors?
Carbon dioxide concentration, light intensity and temperature.
How does light intensity affect plant growth and photosynthesis as a limiting factor?
Light intensity is a limiting factor which limits the rate of photosynthesis when it is in short supply . As light intensity increases the rate of photosynthesis increases up to the a certain rate. Beyond this rate photosynthesis stops measuring even through even though light intensity continues to increase.
How does carbon dioxide concentration affect the rate of photosynthesis and plant growth as a limiting factor?
As the rate of CO2 concentration increases the rate of photosynthesis increases UNTIL a certain point where CO2 no longer acts as a limiting factor.
How does temperature affect photosynthesis and plant growth as a limiting factor?
As the temp increases so does the rate o photosynthesis UNTIL a certain temp after this temp no longer acts as a limiting factor. After a higher temperature the rate of photosynthesis decreases as the enzymes in photosynthesis start to denature.
