Photosynthesis Flashcards
Structure of Chloroplast
Structure:
- Double membrane
- Thylakoids inside chloroplast -> Contains chlorophyll in thylakoid lumen
- Stroma -> Dense fluid surrounding thylakoid discs
Equation of photosynthesis
Energy (From light) + Water (For light depedent) + CO2 (For Calvin Cycle) -> Oxygen (Light dependent product) + Sugar (Calvin Cycle Product)
What is the role of light in photosynthesis?
- Photosystems
- Light energy trapped by chlorophyll pigment molecules
- Energy is then passed into reaction center complex
- Excites electron to higher energy state -> electron transferred to primary electron accepter - Photolysis of water
- Light is involved in photolysis of water
- Electrons produced replenishes the electron in reaction center of photosystem II
Features of light dependent stage
Location: Across thylakoid membrane from stroma to thylakoid space
Reactants: H2O, NADP+, ADP
Products: O2+4H+4e-, NADPH, ATP
Photosystem II -> Photosystem I -> Enters Calvin Cycle
Describe the electron transport chain in light dependent state
- Hydrolysis of water replenishes electrons in Photosystem 2
- Electron enters the electron transport chain -> transported by membrane proteins
- Drives H+ protons from stroma into the thylakoid space -> Creates a proton gradient -> Protons diffuse from thylakoid space to stroma through ATP synthase
- Electrons are used to reduce NADP+ to NADPH at end of chain -> used in kelvin cycle
Features of light independent stage
Location: Stroma
Reactants: 3CO2, 6ATP, 6NADPH
Products: G3P, 6ADP, 6NADP+
- Regenerates ADP and NADP+ for light dependent stage
- Facilitated by enzymes