Photosynthesis Flashcards
What is photosynthesis?
The process by which autotrophs convert light energy into chemical energy in the form of glucose, using carbon dioxide and water.
What is the summary equation for photosynthesis?
6CO2+6H2O+light—>C6H12O6+6O2
Compare the reactants and products of photosynthesis and Calvin cycle.
Photosynthesis: Reactants = CO2,H2O, and light; Products = sugar and O2.
Calvin cycle: Reactants = sugar and O2; Products = CO2, H2O, and ATP.
What are autotrophs?
Organisms that produce their own food using light or chemical energy (e.g., plants, algae).
What are heterotrophs?
Organisms that obtain energy by consuming other organisms (e.g., animals, fungi).
Where does photosynthesis occur?
In the chloroplasts: light-dependent reactions in the thylakoid membranes, and the Calvin cycle in the stroma.
What are the two major stages of photosynthesis?
- Light-dependent reactions: Convert solar energy to ATP and NADPH.
- Calvin cycle: Uses ATP and NADPH to fix carbon into glucose.
What are the two possible results of an electron in an excited state?
- It falls back to a lower energy state, releasing heat or light.
- It is transferred to an electron acceptor in the electron transport chain.
How is ATP synthesized in the light-dependent reactions?
Through chemiosmosis, where ATP synthase uses a proton gradient across the thylakoid membrane to produce ATP.
What reactant contains the oxygen released in photosynthesis?
Water (H_2O).
What supplies electrons to the light-dependent reactions?
Water molecules, which are split into electrons, protons, and oxygen.
Where are the electrons at the end of the light-dependent reactions?
Stored in NADPH, ready to be used in the Calvin cycle.
In what three ways are the light-dependent reactions similar to cellular respiration?
- Both use an electron transport chain.
- Both create a proton gradient for ATP synthesis.
- Both rely on ATP synthase to generate ATP.
What supplies energy for the Calvin cycle?
ATP and NADPH from the light-dependent reactions.
What supplies electrons and hydrogen for the Calvin cycle?
NADPH from the light-dependent reactions.
Where are electrons at the end of the Calvin cycle?
Incorporated into glucose (C6H12O6).
In what form does carbon enter the Calvin cycle?
As carbon dioxide (CO2).
In what form is carbon at the end of the Calvin cycle?
As glucose (C6H12O6).
Is CO2 oxidized or reduced in the Calvin cycle?
Reduced to form glucose.
What happens to ADP and NADP+ produced in the Calvin cycle?
They are recycled back to the light-dependent reactions to regenerate ATP and NADPH.
