The movement of solute molecules across the cell membrane into regions of higher concentrations or against a concentration gradient, using metabolic energy inputs is known as transport active. 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 the molecule to be transported and then interact with membrane transport proteins to move the solute molecule within the cell. E. coli transports several types of sugars (arabinose, maltose, galactose and ribose) and amino acids (glutamate, histidine, leucine) through this mechanism. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay Proton gradients are also used by bacteria, produced during electron transport, to initiate and control active transport. The lactose permease of E.coli transports a lactose molecule inward while a proton simultaneously enters the cell. This linked transport of two molecules in the same direction is called Symport. E.coli also uses proton exchange to absorb amino acids and organic acids such as succinate and malate. A proton gradient can also indirectly power active transport, 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 chained motion in which the transported molecules move in opposite directions is called Anitport. The sodium gradient generated by this proton anitport system then drives 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 altered. For example, Phosphoenolpyruvate: sugar phosphotransferase system (PTS). It transports a variety of sugars while phosphorylating them using phosphoenolpyruvate (PEP) as the phosphate donor. PEP + Sugar (out) ? Pyruvate + Sugar-P (internal) In E. coli and Salmonella typhimurium, 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 often attached to EIIC, a hydrophobic protein embedded in the membrane. Please note: this is just a sample. Get a custom paper from our expert writers now. Get a Custom Assay A high-energy phosphate is transferred from PEP to enzyme II (EII) with the help of enzyme I (EI) and HPr. Then 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 with the PTS, while enzyme I (EI) and HPr are common to all PTSs. PTSs are widely distributed in prokaryotes. Aerobic bacteria do not have PTS. The genera Escherichia, Salmonella, Staphylococcus, and other facultative anaerobic bacteria possess phosphotransferase systems; some obligate anaerobic bacteria (Clostridium) also have PTS. Many carbohydrates are transported by these systems. E. coli absorbs glucose, fructose, mannitol, sucrose, N-acetylglucosamine,.