Chitin Chitin Chitin (CHON) ( ), a long-chain polymer of "N"-acetylglucosamine, is a derivative of glucose. It is a primary component of cell walls in fungi, the exoskeletons of arthropods, such as crustaceans (e.g., crabs, lobsters and shrimps) and insects, the radulae of molluscs, cephalopod beaks, and the scales of fish and lissamphibians. The structure of chitin is comparable to another polysaccharide - cellulose, forming crystalline nanofibrils or whiskers. In terms of function, it may be compared to the protein keratin. Chitin has proved useful for several medicinal, industrial and biotechnological purposes. The English word "chitin" comes from the French word
Glucose cell, it is phosphorylated by glucokinase at position 6 to glucose-6-phosphate, which can not leave the cell. With the help of glucose-6-phosphatase, glucose-6-phosphate is converted back into glucose exclusively in the liver, if necessary, so that it is available for maintaining a sufficient blood glucose concentration. In other cells, uptake happens by passive transport through one of the 14 GLUT proteins. In the other cell types, phosphorylation occurs through a hexokinase, whereupon glucose can no longer diffuse out of the cell. The glucose transporter GLUT1 is produced by most cell types and is of particular importance for nerve cells and