electron transport chain
thylakoids
thylakoids
electron transport chain
The series of molecules through which excited electrons are passed down a thylakoid membrane during photosynthesis is called the electron transport chain. This chain consists of various protein complexes and molecules, such as plastoquinone, cytochrome b6f complex, and plastocyanin, that work together to transfer electrons and generate a proton gradient used to produce ATP.
Ultraviolet Light
Excited electrons in a chlorophyll molecule are transferred through a series of proteins in the thylakoid membrane, known as the electron transport chain, generating ATP and NADPH through the process of photosynthesis. These high-energy molecules will then be used in the Calvin cycle to produce glucose from carbon dioxide.
Electrons become excited in the electron transport chain due to the energy input from electron carrier molecules like NADH and FADH2. These electron carriers donate the electrons to the proteins in the chain, creating a flow of electrons that drives the production of ATP.
An electron transport chain.
In Photosystem II, electrons excited by sunlight are replaced by electrons derived from the splitting of water molecules (photolysis). This process releases oxygen as a byproduct and provides the necessary electrons to replenish those lost by the chlorophyll when it absorbs light energy. In Photosystem I, the excited electrons are eventually transferred to NADP+, forming NADPH, which is crucial for the Calvin cycle in photosynthesis.
The event that accompanies energy absorption by chlorophyll or other pigment molecules of the antenna complex is the excitation of electrons. When light energy is absorbed by the pigment molecules, their electrons get excited to a higher energy state. This excited state is essential for the subsequent transfer of energy to the reaction center of the photosystem for further processing.
The excited electrons flowing through photosystem II come from water molecules that are split during the light-dependent reactions of photosynthesis. This process, known as photolysis, releases oxygen as a byproduct and provides electrons to replace those lost when chlorophyll is excited by sunlight.
The series of electron acceptors in the thylakoid membrane that remove energy from excited electrons to produce ATP is known as the electron transport chain (ETC). As electrons move through the ETC, their energy is used to pump protons across the membrane, creating a proton gradient. This gradient drives ATP synthesis through ATP synthase.