Types of Compounds. Ionic compounds are compounds composed of ions, charged particles that form when an atom (or group of atoms, in the case of polyatomic ions) gains or loses electrons. 1  A cation is a positively charged ion. 2  An anion is a negatively charged ion.
Porins are members of an extended family of transmembrane proteins found in the outer membrane of gram negative bacteria such as E. coli, or in the outer membranes of mitochondria in eukaryotes. The general porins provide a simple diffusion pathway across the membrane for molecules less than 1 kDa with little substrate selectivity.
2,3] This is accomplished by mutations of genes encoding the outer-membrane protein channels called porins. How to overcome resistance These proteins, called porins, are usually employed by bacteria to form channels that allow nutrients to enter through the cell wall. The bacteria in the stone: extra-tiny microorganisms may lead to kidney stones and other diseases