Photosynthesis Flashcards
Equation for photosynthesis.
6CO2 + 6H20 -> C6H12O6 + 6O2
Where does photosynthesis occur and why does it require?
- Occurs in chloroplasts in chlorophyll.
- Requires light energy in form of photons.
How do plants gain organic molecules and what type of species does this make them?
- Plants are photoautotrophs - make own organic molecules using glucose.
What do plants use glucose for?
- For respiration.
Thylakoid definition.
Site of light depend and internal network of membranes that form flattened sacs.
Granum definition
Contain chlorophyll pigment, site of light dependent.
Lamellae
Joins grana
Stroma
Fluid inside chloroplast.
What can can photosynthetic pigments do and what are the different types?
- Can absorb light energy.
- Chlorophyll a = primary photosynthetic pigment
- Chlorophyll b = accessory pigment
Examples of accessory pigments?
- chlorophyll b, carotene, xanthophyll
How to work out RF value?
Spot/solvent
What is the colour of plants that photosynthesise and why?
- Green.
- Contain chlorophyll (green pigment).
- Absorbs red and blue light, but reflect green.
What happens to rate of photosynthesis if you put a plant under a green light only?
Rate of photosynthesis would decrease significantly as the light would be reflected.
What are the two main stages of photosynthesis and what does it involve?
1 - light dependent - involves photosystems - cyclic/non-cyclic photophosphorylation.
2- light independent - involves Calvin cycle.
Where does light dependent stage take place?
In the thylakoid membrane.
What happens during non-cyclic photophosphorylation?
1- light hits PSII, accessory pigment absorbs light and transfer light energy to chlorophyll a, which excited an e-.
2- photolysis of water occurs to replace the e- that chlorophyll a excited.
3- e- is transported to the protein and then PSI, where chlorophyll a also excited an e-.
4- The build up of H+ ions in the thylakoid lumen due to photolysis of water create an electrochemical gradient so chemiosmosis occurs using ATP synthase to counteract charge imbalance.
5- H+ moves through ATP synthase, which creates a proton motive force that turns ADP + Pi into ATP.
6- The H+ and e- joins to NADP, which is the final e- acceptor, forming NaDPH.
What happens during cyclic photophosphorylation?
1- light hits PSI.
2- e- shuttle back and forth from PSI to protein to replace the e- lost.
3- This maintains the electrochemical gradient, so chemiosmosis can occur using ATP synthase.
4- Short e- transport chain. ATP is only product.
