Question

Which form af uptake involves phosphorylation of the substrate as it is taken into the celi 1. ABC transnar: 02 groud translocation 03.cymport 04 all of the above

Answer 1

Transport of molecules across the membrane is a very important and regulated process in the living system. The movement of most of the molecules is generally mediated by membrane transport proteins.

Group translocation involves phosphorylation of the substrate as it is taken into the cell. Group translocation is a type of active transport that is utilized by bacteria for the transport of sugar. After translocation, the transported metabolite is modified. In bacteria, the phosphotransferase system ( group translocation) uses phosphoenolpyruvate (PEP) as an energy source while transport of sugar molecule and the phosphate group is transferred from PEP to sugar moiety. As a result, a phosphorylated substrate is transported inside the cell.

The other two types of transports are not the right answer. Symport involves the transport of two different molecules/ion in the same direction and is performed by a transmembrane integral protein known as symporter. Generally, symport involves the movement of ions down the concentration gradient ( facilitated diffusion) which allows the transport of other molecules against the concentration gradient (active transport). ABC (ATP-binding cassette) transport involves the transport of a variety of substrates including ions, small molecules (sugars, amino acids, vitamins) as well as large molecules (peptides, polysaccharides) by ABC transporter. ABC transporter proteins utilize energy from ATP binding and hydrolysis for the transport of molecules across the membrane. In these two kinds of the transport system, molecules did not get modified after transport across the membrane, so group translocation is right answer.