In the Java programming language, a keyword is one of 50 reserved words that have a predefined meaning in the language; because of this, programmers cannot use keywords as names for variables, methods, classes, or as any other identifier. Due to their special functions in the language, most integrated development environments for Java use syntax highlighting to display keywords in a different colour for easy identification.
Simple definition of a transport system in biology: A transport system is a means by which materials are moved (' transported ') from an exchange surface or exchange surface. to cells* located throughout the organism.* Not all individual cells require all of the many different types of materials carried by a transport system. transport system is a means by which materials are moved (' transported ') from an exchange surface or exchange surface. to cells* located throughout the organism.
Active transport usually happens across the cell membrane. There are thousands of proteins embedded in the cell's lipid bilayer. Those proteins do much of the work in active transport. They are positioned to cross the membrane so one part is on the inside of the cell and one part is on the outside. Only when they cross the bilayer are they able to move molecules and ions in and out of the cell. The membrane proteins are very specific.