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Bmt 206 Assignment - Active Transport and Group Translocation

Autor:   •  April 4, 2011  •  Essay  •  364 Words (2 Pages)  •  2,182 Views

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Cell membrane in bacteria and in all living cell is actually selective permeable; this dynamic structure regulates the movement of substances in and out of cell. Besides, it is also important in order to obtain nutrients and to excrete waste from the cell. Active transport and group translocation carry the same function as one of the four metabolite transport processes cross the cell membrane into cytoplasm.

Active transport is a process whereby the cells use transport protein and metabolic energy to transport substances across the membrane against the concentration gradient. It is also known as energy-coupling device. Active transport is required when the transported species is moving from the low concentration to high concentration and thus need input energy. Concentration of solute in the cytoplasm requires the operation of active transport and there are two types in bacteria; ion driven transport system(IDT) and binding-protein dependent transport system(BPDT). They are also known as major facilitator superfamily( in bacteria, proton motive force drive these transporters. As a proton is allowed into the cell another substance is either brought along or expelled) and ABC transporters( ATP is used as an energy source, extracellular binding proteins deliver a molecule to the transporters. They can also be defined as primary active transport and secondary active transport. Primary active transport gains energy from an exergonic reaction and use the energy for a process directly for example the hydrolysis of ATP. Secondary active transport utilize the energy from the ATP hydrolysis to generate the gradient for another solute and cotransport that solute against the concentration gradient.

Group translocation differs from active transport in several ways. The transported molecule is chemically altered as it passes into the cell. Consequently, uptake of that molecule doesn't affect its concentration gradient. As an example, glucose and several other


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