The movement of ions or molecules across a cell membrane in the direction opposite that of diffusion, that is, from an area of lower concentration to one of higher concentration. Active transport requires the assistance of a type of protein called a carrier protein, using energy supplied by ATP. read more
Definition of transportation for Students. 1 : an act, instance, or means of carrying people or goods from one place to another or of being carried from one place to another. 2 : public carrying of passengers or goods especially as a business. read more
Science. Transportation is the movement of material across the Earth's surface by water, wind, ice or gravity. It includes the physical processes of traction (dragging), suspension (being carried) and saltation (bouncing) and the chemical process of solution. read more
Science is how we invent and improve on all types of technology, including transportation. Transportation is all about technology, and science fuels technology. read more