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The cell suspension is pipetted into a glass or plastic cuvette which has two aluminium electrodes on its sides. For bacterial electroporation, typically a suspension of around 50 microliters is used. Prior to electroporation, this suspension of bacteria is mixed with the plasmid to be transformed. The mixture is pipetted into the cuvette, the ...
The membrane is a homogeneous substance; The electrical field is constant so that the transmembrane potential varies linearly across the membrane; The ions access the membrane instantaneously from the intra- and extracellular solutions; The permeant ions do not interact; The movement of ions is affected by both concentration and voltage differences
Staverman's reflection coefficient, σ, is a unitless constant that is specific to the permeability of a membrane to a given solute. [4] The Starling equation, written without σ, describes the flow of a solvent across a membrane that is impermeable to the solutes contained within the solution. [5]
Fick's first law relates the diffusive flux to the gradient of the concentration. It postulates that the flux goes from regions of high concentration to regions of low concentration, with a magnitude that is proportional to the concentration gradient (spatial derivative), or in simplistic terms the concept that a solute will move from a region of high concentration to a region of low ...
The bacterial cell wall differs from that of all other organisms by the presence of peptidoglycan which is located immediately outside of the cell membrane. Peptidoglycan is made up of a polysaccharide backbone consisting of alternating N-Acetylmuramic acid (NAM) and N-acetylglucosamine (NAG) residues in equal amounts.
In gram-positive bacteria, the cytoplasmic membrane is only surrounded by a thick cell wall of peptidoglycan. By contrast, the envelope of gram-negative bacteria is more complex and consists (from inside to outside) of the cytoplasmic membrane, a thin layer of peptidoglycan, and an additional outer membrane, also called the lipopolysaccharide ...
The composition of the outer membrane is distinct from that of the inner cytoplasmic cell membrane - among other things, the outer leaflet of the outer membrane of many gram-negative bacteria includes a complex lipopolysaccharide whose lipid portion acts as an endotoxin - and in some bacteria such as E. coli it is linked to the cell's ...
Cells can be up to 10 cm long, and are separated by a small septum. [17] Small holes in the septum allow cytoplasm and cytoplasmic contents to flow from cell to cell. Osmotic pressure gradients occur through the length of the cell to drive this cytoplasmic flow. Flows contribute to growth and the formation of cellular subcompartments. [17] [18]