To avoid ”reinventing the wheel”, we heavily rely on the excellent site HyperPhysics, hosted by the Department of Physics and Astronomy of University of Georgia. Their material is excellent for discussing engineering electricity, where the charge carriers are electrons. However, they extended their material with bioelectric phenomena, tacitly agreeing with some fallacies created by biophysics. They do not scrutinize the differences caused in the electric phenomena by the structure of living matter, the effects of the limited volume of a cell, using slow positive ions in electrolytic solutions instead of fast free electron clouds in solids, the interaction with thermodynamics, among others. So, we must discuss the deviations in detail, which originate from the same reasons as discussed in section 2.4.1.
One of the famous dichotomies (see section 2.2.4) is that there exist laws, separately, for continuous and discrete electricity, without providing a transition between them. The fundamental concepts are the same, but we must rethink several approximations. Furthermore, sometimes we must consider the classical continuous electricity, sometimes particle-based electricity; sometimes the mixture of the two, or a transition between them. In biological cells, the usual ”infinite” conditions (infinitely far, infinitely small, etc.) of the classical electronics are not fullfilled: it depends on the context what can be omitted with respect to some other quantity or size. Say, the charge in the intracellular volume is ”infinitely smaller” than that in the extracellular volume, but ”infinitely larger” than the charge handled in an ion-channel-related operations. The biological organization prevents discussing living matter as homogeneous and isotrop medium, the active ”charge production” in some biological constructions needs a precise interpretation of the conservation laws, and the charge carriers’ speed needs revisiting the interpretation of the fundamental physical laws.