Where there was one cell there are two, then four, then eight,..
Mitosis and Meiosis - Pearson - The Biology Place
Active transporters. These use the energy from the hydrolysis of ATP to transport substances against their prevailing electrochemical gradient. The classic example to which you refer is the sodium pump (also known as the Na+-K+ ATPase). This is an ATPase present in the cell membrane that transfers 3 sodium ions out of the cell in exchange for 2 potassium ions into the cell (both against their electrochemical gradient) at the expense of the consumption of one molecule of ATP. It plays a vital role in the maintenance of a low sodium and high potassium concentration within cells. It therefore is fundamental in maintaining the driving force for many sodium-dependent secondary active transporters. In direct answer to your question, the sodium pump is not the only active transporter.
There are other ATPases responsible for transporting protons, calcium
ions, as well as larger molecular weight substrates. There are also ATPases present in the organellar membranes. For example, a calcium ATPase in the sarcoplasmic reticulum of muscle cells plays a fundamental role in relaxation of muscle following calcium-dependent contraction. In one important example, the movement of the substrate down its electro-chemical gradient is used to drive the synthesis of ATP: This is the F1F0 ATPase of mitochondria.
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Eduard Zenkevich (born in 1945): graduated from Belarussian State University (1967, Minsk, Belarus), PhD Degree (1973), Doctor Habil. (1990). Full Professor of Physics (1998, Institute of Molecular and Atomic Physics, NAS of Belarus), Full Professor of Physics (2007, Belarussian National Technical University). Main research activities: structure/relaxation dynamics relationships in nanoscale self-assembled objects: multiporphyrin structures, pigment-protein complexes, “semiconductor quantum dot – dye molecule” nanocomposites. Visiting professor and lecturer at the Institute of Physics, University of Technology Chemnitz (1993-2016, Germany); accredited expert of Russian Corporation of Nanotechnologies “ROSNANO” (2010). The total list of publications includes more than 200 publications in refereed periodicals, two books.