What is the transmission of the membrane?

Animal cells have a selectively permeable membrane that surrounds them that separates the content of the cell interior from the external environment. The process by which ions and small soluble molecules or soluts pass through the cell membrane are called the transport of membranes. These molecules are usually substances vital to the function and maintaining cells such as glucose and amino acid. There are four main types of membrane transport: passive diffusion or simply diffusion; Essed diffusion; primary active transport; and secondary active transport. Many of these transport mechanisms include the use of specialized proteins located in the cell membrane called transport proteins of the membrane.

Passive diffusion occurs spontaneously and is powered by a random activity of molecules in solution. Molecules move from the area of ​​high concentration, where many of them are densely packed together, to the low concentration area, where they are less molekules. Small molecules can achieve tRansport of diffusion diaphragm over the cell membrane. The diffusion rate can be influenced by many things, including the composition of the cell membrane and the size and charge of the molecule. The most famous type of passive diffusion is osmosis, the process involving the movement of water molecules from the area of ​​high concentration into the area of ​​lower concentration.

The

facus facilitates the use of the membrane transport proteins in the cell membrane called channel proteins. These proteins act as pores in the cell membrane, allowing to go through the water -soluble particles, but in addition to passing lipophilic or "loving fats" of molecules. Diffusion monitors the same mechanism of action, with molecules moving from areas with high concentration to areas with low concentration.

Primary active transport uses energy and molecules from areas with high concentrations to areas with low concentration. The energy needed to run the primary assetsThe transport is usually in the form of nucleotide called adenosine triphosphate (ATP). One of the most common forms of active transport is the sodium-aposia pump, which helps cells to maintain an electric charge known as resting potential and also controls the volume of cells. The sodium-aposia pump moves sodium ions into the outside of the cell and releases potassium ions into the cell cytoplasm.

Secondary active transport uses transport proteins called antiporters and symptors. Antiporters move ions and molecules by transporting one type of particle against its usual concentration gradient, from low to high concentration, in the transport of another type of particle in normal way, from high concentration. Symps are transported by two different types of molecules or ion over the cell membrane at the same time and in the same direction.