Even though transport proteins are involved in facilitated diffusion, it is still considered passive transport because the solute is moving down its concentration gradient. Facilitated diffusion speeds up the transport of a solute by providing an efficient passage through the membrane, but it does not alter the direction of transport.
Active transport requires energy to move a solute against its concentration gradient. As in most other cellular work, ATP will most often provide this energy, usually by transferring its terminal phosphate group directly to the transport protein.
With ATP, the donated phosphate group induces the transport protein to change its shape in a manner that translocates the solute bound to the protein across the membrane. This works with the sodium-potassium pump, which
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They cross the membrane with no energy expenditure from the cell. The rate of this diffusion can be sped up by transport proteins in the membrane. Examples of passive transport include diffusion, osmosis, and facilitated diffusion. Active transport moves substances against their concentration gradient, from an area of low concentration to high concentration. Carrier proteins do this, acting as pumps that require energy, typically ATP, to function. Some examples include the sodium-potassium pump, exocytosis, and endocytosis.
All cells have voltages across their plasma membranes, which is electrical potential energy. The voltage across a membrane is called membrane potential, which is dependent on the charge of the area. Two forces drive the diffusion of ions across a membrane: a chemical force, or in this case, or the ion 's concentration gradient, and an electrical force, or the effect of the membrane potential on an ions movement.
An anion is a negatively charged ion. A cation is a positively charged