Elektrontranszportláncban

Elektrontranszportláncban, often abbreviated as ETC, refers to the electron transport chain, a fundamental process in cellular respiration and photosynthesis. In cellular respiration, it is the final stage where the majority of ATP, the energy currency of cells, is produced. Electrons, carried by molecules like NADH and FADH2, are passed along a series of protein complexes embedded in the inner mitochondrial membrane. As electrons move from one complex to another, energy is released, which is used to pump protons (H+) from the mitochondrial matrix to the intermembrane space. This creates an electrochemical gradient. Protons then flow back into the matrix through an enzyme called ATP synthase, driving the synthesis of ATP from ADP and inorganic phosphate.

In photosynthesis, a similar electron transport chain operates within the thylakoid membranes of chloroplasts. Light energy is used to excite electrons, which then travel through a series of protein complexes. This process also generates a proton gradient across the thylakoid membrane, which powers ATP synthesis. Additionally, electrons from the photosynthetic ETC are used to reduce NADP+ to NADPH, another crucial energy-carrying molecule. The ETC is therefore vital for converting light energy into chemical energy in plants and for generating the bulk of ATP in aerobic organisms. The efficiency and precise mechanisms of ETC vary between different organisms and cellular contexts.