The movement of solute molecules across the cell membrane toward regions of higher concentrations or against a concentration gradient, with the use of an influx of Metabolic energy is known as active transport. Binding protein transport systems or ATP-binding cassette transporters (ABC transporters) are a good example of active active transport in bacteria, archaea and eukaryotes. These transporters are an example of ATP-dependent pumps. ABC transporters are ubiquitous membrane-bound proteins. These pumps can transport substrates into or out of cells. These binding proteins bind to the molecule to be transported and then interact with membrane transport proteins to move the solute molecule inside the cell. E. coli transports different types of sugars (arabinose, maltose, galactose and ribose) and amino acids (glutamate, histidine, leucine) by this mechanism. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get the original essay Proton gradients are also used by bacteria, produced during electron transport, to initiate and control active transport. E.coli lactose permease transports a lactose molecule inward when a proton simultaneously enters the cell. Such linked transport of two molecules in the same direction is called Symport. E.coli also uses a proton symport to absorb amino acids and organic acids like succinate and malate. A proton gradient can also drive active transport indirectly, often through the formation of a sodium ion gradient. In E. coli, the sodium transport system pumps sodium outward in response to the inward movement of protons. The linked motion in which the transported molecules move in opposite directions is called Anitport. The sodium gradient generated by this proton antiport system then leads to the absorption of sugars and amino acids. E.coli at least has transport systems for the sugar galactose. Group translocation is a process in which a molecule is transported into the cell while being chemically modified. For example, Phosphoenolpyruvate: sugar phosphotransferase system (PTS). It transports a variety of sugars while phosphorylating them using phosphoenolpyruvate (PEP) as a phosphate donor. PEP + Sugar (outside)? Pyruvate + Sugar-P (inside) In E. coli and Salmonella typhimurium, it involves two enzymes and a low molecular weight heat-stable protein (HPr). HPr and enzyme I (EI) are cytoplasmic. Enzyme II (EII) has a more variable structure and often consists of three subunits. EIIA is cytoplasmic and soluble. EIIB is also hydrophilic but is frequently attached to EIIC, a hydrophobic membrane-embedded protein. Keep in mind: this is just a sample. Get a personalized article from our expert writers now. Get a Custom Essay A high energy phosphate is transferred from PEP to Enzyme II (EII) with the help of Enzyme I (EI) and HPr. Next, a sugar molecule is phosphorylated as it is transported across the membrane by enzyme II (EII). Enzyme II (EII) transports only specific sugars and varies by PTS, while enzyme I (EI) and HPr are common to all PTS. PTS are widely distributed among prokaryotes. Aerobic bacteria lack PTS. The genera Escherichia, Salmonella, Staphylococcus, and other facultative anaerobic bacteria possess phosphotransferase systems; certain bacteria.