Electrons have four important roles in biological systems: forming covalent bonds, transferring energy from the environment, forming free radicals, and which other function?

The fourth role in biological systems of the electrons is to form ions

Explanation:

Ion is an atomic or molecular particle that is electrical charged. This occurs, because there is an imbalance between the amount of protons and electrons in the particle. Ions are important in biological systems because:

Metals are mostly in ionic form in the nature. And metals are very important for several reactions at the cellular level of living organisms. For example, about 30% of all proteins in cells.