What are the electron donors in photosynthesis?

What are the electron donors in photosynthesis?

In oxygenic photosynthesis, H2O serves as the electron donor to replace the reaction center electron, and oxygen is formed as a byproduct. In anoxygenic photosynthesis, other reduced molecules like H2S or thiosulfate may be used as the electron donor; as such, oxygen is not formed as a byproduct.

What is the main electron donor in photosystem 1?

chlorophyll
The primary electron donor of photosystem I, P700, is a chlorophyll species that in its excited state has a potential of approximately -1.2 V. The precise chemical composition and electronic structure of P700 is still unknown. Recent evidence indicates that P700 is a dimer of one chlorophyll (Chl) a and one Chl a’.

What is the electron donor in photosystem II?

chlorophyll a
The primary electron donor of photosystem II is a special form of chlorophyll a known as P680.

What are examples of electron donors?

Electron Donors and Acceptors Inorganic electron donors include hydrogen, carbon monoxide, ammonia, nitrite, sulfur, sulfide, and ferrous iron. The use of inorganic electron donors as an energy source is of particular interest in the study of evolution. NADH is the electron donor and O2 is the electron acceptor.

Is oxygen an electron donor in photosynthesis?

Is oxygen an electron donor or acceptor in photosynthesis?

The final electron acceptor is NADP. In oxygenic photosynthesis, the first electron donor is water, creating oxygen as a waste product. In anoxygenic photosynthesis various electron donors are used. Cytochrome b6f and ATP synthase work together to create ATP.

What is the main function of photosystem 1?

Photosystem I (PSI) of photosynthesis (Fig. 1) provides energy to reduce NADP to NADPH, which is required for carbon fixation and other synthetic processes.

What are the photosystems I and II in photosynthesis?

There are two types of photosystems: photosystem I (PSI) and photosystem II (PSII). Both photosystems contain many pigments that help collect light energy, as well as a special pair of chlorophyll molecules found at the core (reaction center) of the photosystem.

Does photosynthesis occur in algae?

Photosynthesis is the process by which light energy is converted to chemical energy whereby carbon dioxide and water are converted into organic molecules. The process occurs in almost all algae, and in fact much of what is known about photosynthesis was first discovered by studying the green alga Chlorella.

Why are photosystems not in the electron transport chain?

Photosystem I and II don’t align with the route electrons take through the transport chain because they weren’t discovered in that order. Photosystem I was discovered first. Later, photosystem II was discovered and found to be earlier in the electron transport chain. But it was too late, the name stuck.

How is NADPH used in the electron transport chain?

Chlorophyll, which is present in the photosystems, soaks up light energy. The energized electrons are then used to make NADPH. The electron transport chain is a series of molecules that accept or donate electrons easily. By moving step-by-step through these, electrons are moved in a specific direction across a membrane.

How is ATP created in the electron transport chain?

The Electron Transport Chain. This means that when electrons are moved, hydrogen ions move too. ATP is created when hydrogen ions are pumped into the inner space (lumen) of the thylakoid. Hydrogen ions have a positive charge. Like in magnets, the same charges repel, so the hydrogen ions want to get away from each other.

How are hydrogen ions transported down the electron transport chain?

They escape the thylakoid through a membrane protein called ATP synthase. By moving through the protein they give it power, like water moving through a dam. When hydrogen ions move through the protein and down the electron transport chain, ATP is created. This is how plants turn to sunlight into chemical energy that they can use.