Passive transport-means moving biochemicals and other atomic or molecular substances across membranes. This process does not involve chemical energy because, unlike in an active transport, the transport across membrane is always coupled with the growth of entropy of the system. So passive transport is dependent on the permeability of the cell membrane, which, in turn, is dependent on the organization and characteristics of the membrane lipids and proteins. The four main kinds of passive transport are diffusion, facilitated diffusion, filtration and osmosis.
Active transport is the movement of a substance against its concentration gradient this is usually concerned with accumulating high concentrations of molecules that the cell needs, such as ions, glucose, and amino acids. If the process uses chemical energy, such as from adenosine triphosphate (ATP), it is termed primary active transport.
Active transport uses energy, unlike passive transport, which does not use any type of energy.Active transport is a good example of a process for which cells require energy.
- Examples of active transport include the uptake of glucose in the intestines in humans and the uptake of mineral ions into root hair cells of plants.
- Water, ethanol, and chloroform exemplify simple molecules that do not require active transport to cross a membrane.
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