What Is an Ion Channel?
Operation of cells in the nervous system, contraction of the heart and of skeletal muscle, and secretion in the pancreas are examples of physiological processes that require ion channels. In addition, ion channels in the membranes of intracellular organelles are important for regulating cytoplasmic calcium concentration and acidification of specific subcellular compartments.
Permeation through the comparatively wider and less selective Na+ channels also proceeds via a loosely coupled knockon mechanism, although the ions do not need to be fully dehydrated. While simple structural concepts are often invoked to rationalize the mechanism of ion selectivity, a deeper analysis shows that subtle effects play an important role in these flexible dynamical structures.
Therefore the daphnia can be used for educational purposes in undergraduate study.
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Bagneris C, Naylor CE, McCusker EC, Wallace BA. Structural model of the open-closed-inactivated cycle of prokaryotic voltage-gated sodium channels. The Journal of general physiology. 2015