Photosynthesis Test Flashcards
How do plants obtain water?
Through their roots
Where does photosynthesis take place?
In thylakoids in chloroplasts
(Thylakoids stack into grana)
(Surrounded by stroma)
How do plants obtain CO2?
Through the stomata
Photosynthesis equation
Energy + 6CO2 + 6H2O —> C6H12O6 + 6O2
What becomes reduced/oxidized in photosynthesis?
CO2 reduced to C6H12O6
H2O oxidized to O2
4 achievements in light reaction?
- Splits H2O
- Release O2
- Reduces NADP+ to NADPH
- Creates ATP from ADP using photophosphorylation
What do chlorophyll a, b, and carotenoids do?
They are pigments and absorb light in the visible spectrum for the plant in order to perform photosynthesis.
Carotenoids absorb light that could harm chlorophyll a or b as well
Which wavelengths are shorter?
Which have more energy?
ROYGBIV
- ———> shorter wavelengths
- ———> more energy
Are the light cycle and Calvin cycle dependent on each other?
Yes, the Calvin cycle requires ATP and NADPH from the light cycle and returns ADP and NADP+
Which photo system comes first?
Photo system 2
Describe what happens in photo system 2
Light hits a electron and it becomes excited. It jumps between chlorophyll molecules and gets to p680. From there, it is given to the primary acceptor and then the electron transport chain. After the electron leaves. P680 becomes p680+ and 2 electrons from a water molecule enter
Describe the electron transport chain
It includes pq, the cytochrome complex, and pc
Describe Photosystem 1
The electron enters from the etc and jumps through chlorophyll to p700, where it heads to the primary acceptor and leaves. After it leaves, p700 becomes p700+
What happens to an electron after photosystem 1?
It heads to ferredoxin, where it can be recycled to the electron transport chain or head to the NADP+ reductase enzyme, which produces NADPH
How is ATP made in the light reactions?
ATP synthase has a spinning top from protons passing through it and it synthesizes ATP
What are the Calvin cycle phases?
- Carbon fixation
- Reduction
- Regeneration of the CO2 acceptor (RuBP)
Describe the Calvin cycle
3 carbon atoms enter one at a time, forming 3 of a short lived intermediate, then 6 3PGA. Then 6 ATP are added to make 6 1,3 biphosphoglycerate and 6 NADPH are added and 6 NADP+ and released along with 6 phosphates.
Then 6 G3P forms, one is released for glucose and other compounds. 5 G3P continue in the cycle and 3 ATP are added and 3 ADP are released. This creates 3 RuBP which bonds with carbon in the rubisco enzyme to restart the cycle.
What is the difference between c3, c4, and cam plants?
C3: creates a 3 carbon molecule in the first stage of the Calvin cycle.
C4: creates a 4 carbon molecule in stage 1 of the Calvin cycle, has cycle occur in two different cells
CAM: first stage at night, the rest during day and fixes the carbon into an organic acid
