However, the brightness of a star depends on its composition and how far it is from the planet. Astronomers define star brightness in terms of apparent magnitude â how bright the star appears from Earth â and absolute magnitude â how bright the star appears at a standard distance of 32.6 light-years, or 10 parsecs.
What is the electron transport chain? A: The electron transport chain is a chemical reaction where electrons are transferred from a high-energy molecule to a low-energy molecule. These reactions can be used to convert energy from sunlight in photosynthesis or extract energy from sugars in respiration. The electron transport chain is critical to the production of adenosine triphosphate, or ATP, which is a source of energy for living things.
In the mitochondrial electron transport chain electrons move from an electron donor (NADH or QH 2) to a terminal electron acceptor (O 2) via a series of redox reactions. These reactions are coupled to the creation of a proton gradient across the mitochondrial inner membrane.lectron transport chains are redox reactions that transfer electrons from an electron donor to an electron acceptor. The transfer of electrons is coupled to the translocation of protons across a membrane, producing a proton gradient. The proton gradient is used to produce useful work.