Photosynthesis Flashcards
When an atom or molecule is _________ it loses an electron
OXIDIZED
When an atom or molecule is _________ it gains an electron
REDUCED
Define:
The process in which plants and other photosynthetic organisms capture and convert light energy from the sun into chemical energy
Photosynthesis
What is the formula for photosynthesis?
6 H2O + 6 CO2 + light —–> C6H12O6 + 6 O2
Where does the light-dependant reaction occur?
The thylakoid membrane
What is a photosystem?
Clusters of chlorophyll and other pigments embedded in the thylakoid membrane
What are the two photosystems in chloroplasts
Photosystem I (PSI) & Photosystem II (PSII)
What are the steps of Photosystem II
- Light enters
- Photons excite chlorophyll molecules
- Light energy transferred to reaction center
- Photolysis occurs (splitting of water - H4 & O2)
- Oxygen released
- Hydrogen accumulates inside thylakoid lumen/space
- Hydrogen electrons are transferred to Photosystem I via electron transport chain
Define:
Chemiosmosis
Hydrogen electrons are pulled into the ATP synthesis enzyme due to concentration gradient and the the energy stored in the gradient is used to make ATP
What are the steps of Photosystem I
- Electrons move through the transport chain to PSI
- More light enters
- Chemiosmosis occurs - Hydrogen electrons are pulled into the ATP synthesis enzyme due to concentration gradient
- NADP+ combines with H+ to make NADPH
What are the products of the light-dependant reaction?
- NADPH
- Separate Oxygen and hydrogen ions
- ATP
What is ATP
- ATP is a byproduct of photosynthesis
- ATP supplies the energy for cellular function (transport, cell division, cell movement, muscle contraction, etc.)
ATP releases energy when the bond of the 3rd phosphate groups breaks, creating ADP
How is ADP formed?
ATP releases energy when the bond of the 3rd phosphate groups breaks, creating ADP
Where does the light-independent reaction (Calvin Cycle) occur?
Takes place in stroma
What is required for the Calvin Cycle to take place? (reactants)
Reactants required:
- ATP
- NADPH
- CO2