Photosynthesis in C3 plants Flashcards
What do the stomata do?
Open up to allow O2 to leave (prevent photorespiration) and allow CO2 to enter
Also limits water loss
Light dependent
Location: Grana
- Light splits water into H+ and Oxygen
- H+ is picked up by NADP to form NADPH
- Energy from splitting water is stored as ATP
- ATP and NADPH move onto the light-independent
Inputs and outputs of light dependent
Inputs : NADP, H20, ADP
Outputs: O2, NADPH, ATP
Light independent
Location: Stroma
- CO2 enters the calvin cycle
- Rubisco fixes CO2 into 3-PGA
- Then, that is reduced to PGAL by NADPH and ATP
- PGAL is used to create glucose
- NADP and ADP return to the light dependent stage
Inputs and outputs of light independent
Inputs: CO2, NADPH, ATP
Outputs: Glucose, NADP, ADP, H2O (as a byproduct)
What is Rubisco
An enzyme that binds to CO2 to ‘fix’ the carbon into 3-PGA
- a molecule used to initiate the Calvin Cycle
What does photorespiration do?
- Less glucose for the plant
- Wasted energy
- Plant cannot grow and reproduce
What are the disadvantages of Rubisco
Sometimes it uses Oxygen as a substrate instead of CO2… Which causes photorespiration
What are factors that affect Rubisco’s ability to catalyse
- Temperature
- Substrate concentration
How does outside temperatures (substrate concentration) affect Rubisco?
- In hotter temperatures, the stomata close, keeping the O2 in and CO2 out, causing photorespiration
How does temperature affect Rubisco?
- Temperature: In higher temperatures, Rubisco is more likely to bind to Oxygen than CO2
Describe the structure of chloroplasts
Stroma: Light-independent stage, gel-like, enriched in enzymes
Grana: Light-dependent stage, grana stacks
Photosynthesis equation
6CO2 + 6H2O → C6H12O6 + 6O2
