A series of electron carrier molecules that shuttle electrons during a series of redox reactions that release energy used to make ATP; located in the inner membrane of mitochondria, the thylakoid membranes of chloroplasts, and the plasma membranes of prokaryotes.
Electron transport chain (ETC)
The process is called electron transport chain (ETC). It is a crucial part of cellular respiration in mitochondria and photosynthesis in chloroplasts. The main function of the electron transport chain is to generate adenosine triphosphate (ATP), which is the main energy currency of the cell.
In mitochondria, the electron transport chain is located in the inner membrane. In chloroplasts, it is found in the thylakoid membranes. In prokaryotes, it is present in the plasma membrane. This localization allows for proper compartmentalization and efficient functioning.
The electron transport chain consists of a series of electron carrier molecules, also known as respiratory complexes or protein complexes. These molecules are embedded within the membrane and are organized in order of increasing reduction potential from one end to the other.
During cellular respiration, high-energy electrons from molecules such as NADH (Nicotinamide adenine dinucleotide) and FADH2 (Flavin adenine dinucleotide) are fed into the electron transport chain. The electrons are then passed along a series of protein complexes, each of which plays a specific role in the sequential transfer of electrons.
As the electrons move through the electron transport chain, their energy levels decrease, and this energy is used to pump protons (H+) across the membrane from the matrix (inner compartment of the mitochondria) or stroma (inner compartment of the chloroplasts) to the intermembrane space or lumen. This establishes an electrochemical gradient, with more protons on one side of the membrane than the other.
The final destination of the electron transport chain is an enzyme called ATP synthase. This enzyme uses the energy from the proton gradient to convert adenosine diphosphate (ADP) to ATP in a process called oxidative phosphorylation. ATP is then released and made available for cellular activities.
Overall, the electron transport chain extracts energy from high-energy electrons and utilizes it to pump protons across the membrane, creating a proton gradient. The potential energy stored in this gradient is then used to produce ATP. This process is vital for the functioning of cells and is an excellent example of how cells efficiently utilize energy.
More Answers:
Harnessing the Power of Chemiosmosis: ATP Production during the Light Reactions of PhotosynthesisThe Role of Photosystem II and Photosystem I in Electron Transfer and NADPH Production
The Role of Chloroplasts in Photosynthesis: The Significance of the Transfer of Light-Excited Electrons to Primary Electron Acceptors