What is photosynthesis?
The process that converts solar energy into chemical energy
It occurs in plants, algae, and cyanobacteria.
What are photoautotrophs?
Organisms that use light to manufacture their own food
Examples include plants and some bacteria.
What are heterotrophs?
Organisms that must feed on other organisms to get energy
Examples include animals and fungi.
What is the general equation for photosynthesis?
C6H12O6 + 6O2 + 6CO2 + 6H2O + Energy (Sunlight)
This summarizes the inputs and outputs of the process.
Where does photosynthesis take place?
In chloroplasts
Chloroplasts are the organelles responsible for photosynthesis in plant cells.
What is a photosystem?
A reaction-center complex surrounded by light-harvesting complexes
It plays a crucial role in the process of photosynthesis.
What do light-harvesting complexes do?
Transfer the energy of photons to the reaction center
They consist of pigment molecules bound to proteins.
What is a primary electron acceptor?
A molecule that accepts excited electrons in the reaction center
It is reduced as a result of accepting these electrons.
Which photosystem functions first in photosynthesis?
Photosystem II (PSII)
It is best at absorbing a wavelength of 680 nm.
What is the reaction-center chlorophyll a of Photosystem II called?
P680
This name reflects its optimal absorption wavelength.
What is the optimal absorption wavelength for Photosystem I (PSI)?
700 nm
PSI functions after PSII in the photosynthetic process.
What is the reaction-center chlorophyll a of PSI called?
P.700
P.700 is crucial for the photosynthetic process.
What happens when a photon hits a pigment in the photosystem?
Its energy is passed to the pigment
This energy transfer is essential for initiating the photosynthetic process.
What is transferred to the primary electron acceptor from P680+?
Electrons from hydrogen atoms
This process reduces P680+ and releases O2 as a by-product.
What is released as a by-product when H2O is split by enzymes?
O2
The splitting of water is a critical step in photosynthesis.
What drives the creation of a proton gradient across the thylakoid membrane?
Energy released by electrons falling down the electron transport chain
This gradient is essential for ATP synthesis.
In PS I, what happens to P700 when it is excited by transferred light energy?
It loses an electron to an electron acceptor
This process is similar to what occurs in PS II.
What do the excited electrons in PS I fall down towards after being transferred?
The protein ferredoxin (Fd)
This transfer is part of the electron transport chain.
What is NADP+ reduced to during the photosynthetic process?
NADPH
NADPH becomes available for the reactions of the Calvin cycle.
What is removed from the stroma during the electron transfer process?
An electron
This removal is part of the overall electron transport mechanism.
What are the products produced on the side facing the Stroma during photosynthesis?
- ATP
- NADPH
These products are essential for the Calvin cycle, which takes place in the Stroma.
The Calvin cycle uses the chemical energy of ATP and NADPH to reduce _______ to sugar.
CO2
The cycle builds sugar from smaller molecules using ATP and the reducing power of electrons carried by NADPH.
What is the sugar produced at the end of the Calvin cycle?
glyceraldehyde 3-phosphate (G3P)
For net synthesis of one G3P, the cycle must take place three times, fixing three molecules of CO2.
Name the three phases of the Calvin cycle.
- Carbon fixation
- Reduction
- Regeneration of the CO2 acceptor
Each phase plays a critical role in the overall process of photosynthesis.
