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.
Answers. Best Answer: An electron transport chain couples a chemical reaction between an electron donor (such as NADH) and an electron acceptor (such as O2) to the transfer of H+ ions across a membrane, through a set of mediating biochemical reactions.nswers. Best Answer: An electron transport chain couples a chemical reaction between an electron donor (such as NADH) and an electron acceptor (such as O2) to the transfer of H+ ions across a membrane, through a set of mediating biochemical reactions.