Molecular Mechanisms of Ion Transport: New Insights by Patch-Clamp Studies
New insights into the molecular processes involved in ion and nutrient transport across membranes of animal and plant cells were obtained since the application of the patch-clamp technique to isolated cells, protoplasts (wall-free plant cells) and organelles. While excitable electrical behaviour was first observed in plant cells about a century ago, the underlying mechanisms are only now being directly studied at the molecular level. Ion channels are integral transmembrane proteins which, when open, allow the movement of ions and some non-electrolytes down their electrochemical potential gradients. Although ion currents in plant cells were among the first to be studied in detail, the electrophysiological characterization of plant ion channels has been somewhat slower compared to their animal counterparts. This has been due to problems specific to plants, such as the presence of the cell wall, having the plasma membrane and vacuolar membrane in series separated by only a relatively small cytoplasmic compartment.
KeywordsVacuolar Membrane Single Channel Conductance Membrane Patch Electrical Potential Difference Inner Mitochondrial Membrane
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