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Active absorption refers to the absorption of water by roots with the help of adenosine triphosphate, generated by the root respiration: as the root cells actively take part in the process, it is called active absorption. According to Jenner, active absorption takes place in low transpiring and well-watered plants, and 4% of total water ...
A more common definition is that "Absorption is a chemical or physical phenomenon in which the molecules, atoms and ions of the substance getting absorbed enter into the bulk phase (gas, liquid or solid) of the material in which it is taken up." A more general term is sorption, which covers absorption, adsorption, and ion exchange. Absorption ...
There are two types of active transport: primary active transport that uses adenosine triphosphate (ATP), and secondary active transport that uses an electrochemical gradient. This process is in contrast to passive transport , which allows molecules or ions to move down their concentration gradient, from an area of high concentration to an area ...
Active transport is the movement of a substance across a membrane against its concentration gradient. This is usually to accumulate high concentrations of molecules that a cell needs, such as glucose or amino acids. If the process uses chemical energy, such as adenosine triphosphate (ATP), it is called primary active transport.
In cell biology, ion trapping is the build-up of a higher concentration of a chemical across a cell membrane due to the pKa value of the chemical and difference of pH across the cell membrane. [ 1 ] [ 2 ] This results in basic chemicals accumulating in acidic bodily fluids such as the cytosol , and acidic chemicals accumulating in basic fluids.
The adsorption rate is dependent on the temperature, the diffusion rate of the solute (related to mean free path for pure gas), and the energy barrier between the molecule and the surface. The diffusion and key elements of the adsorption rate can be calculated using Fick's laws of diffusion and Einstein relation (kinetic theory) .
ADME is the four-letter abbreviation (acronym) for absorption, distribution, metabolism, and excretion, and is mainly used in fields such as pharmacokinetics and pharmacology. The four letter stands for descriptors quantifying how a given drug interacts within body over time.
Though bioaccumulation and biosorption are used synonymously, they are very different in how they sequester contaminants: . Biosorption is a metabolically passive process, meaning it does not require energy, and the amount of contaminants a sorbent can remove is dependent on kinetic equilibrium and the composition of the sorbents cellular surface. [9]