Difference between active and passive transport
Molecules move through concentration gradient in different ways, namely active and passive transport. The concentration gradient is the gradual change that occurs in particles in a solution and the gradient happens when the ions are unevenly distributed across the membrane of the cell. When the particles move against the gradient, this is called an active transport. When the particles move with the gradient, this is called a passive transport.
We can use digestion as a way of illustrating this concept. It is important for us to eat to supply the body with the nourishment that it needs. The body takes the nutrients from the food in the digestive process and transports them to the individual organs and cells where they are most needed. Both active and passive transport takes place inside the body in this process because the concentration gradients that surround the cells are different.
The concentration gradient found inside the cells of the body is higher than it is on the outside. This means that the molecules being transported to the cells are moving against the gradient. Therefore this process uses active transport. However, when the molecules must be moved out of the cells, when they are burned out or in the case of waste, they are moving from higher to lower concentration gradients and therefore passive transport is used.
It requires more energy for active transport to take place. This energy generally comes from ATP, Adenosine Triphosphate, which is necessary to move molecules from lower concentration gradients to higher ones. It doesn’t require any energy at all for passive transport to take place because the movement of molecules from higher to lower concentration gradients automatically occurs.
Active and passive transport each have a role to play in making sure that molecules are brought to where they are needed at any given time. This process takes place in all living things and is not a process that is unique to the human body. For example, passive transport occurs when warm air moves into cold air and active transport takes place when cold air moves into warm air.