Active and Passive Transport
“Active transport is the movement of molecules across a membrane from a region of lower concentration to a region of higher concentration against the concentration gradient.”
“Passive transport is the movement of molecules across the membrane without the help of energy.”
Active and passive transport are the two main biological processes that play a crucial role in supplying nutrients, oxygen, water, and other essential molecules to the cells along with the elimination of waste products. Both active and passive transport works for the same cause, but with different movement.
Let us see how active and passive transport are different from each other.
Difference Between Active And Passive Transport
Following are the important difference between active and passive transport:
| Active Transport | Passive Transport |
| Requires cellular energy. | Do not require cellular energy. |
| It circulates from an area of lower concentration to a region of higher concentration | It circulates from a region of higher concentration to a region of lower concentration |
| Required in the transportation of all the molecules such as proteins, large cells, complex sugars, ions, etc. | Required in the transportation all the soluble molecules which include oxygen, water, carbon dioxide, lipids, sex hormones, monosaccharides, etc. |
| It transports various molecules in the cell. | It is involved in the maintenance of the equilibrium level inside the cell. |
| Active transport is a dynamic process. | Passive Transport is a physical process. |
| It is highly selective. | It is partly non-selective |
| Active transport is a rapid process. | Passive transport is a comparatively slow process. |
| Transpires in one direction. | Transpires bidirectionally. |
| Active transportation is influenced by temperature. | Passive transportation is not influenced by temperature. |
| In Active transport carrier proteins are required | In passive transport carrier proteins are not required |
| This process reduces or halts as the oxygen content level is reduced. | This process is not affected by the level of oxygen content. |
| Metabolic inhibitors can influence and stop the active transport. | Passive transportation is not influenced by metabolic inhibitors. |
| Different types of Active Transport are – Exocytosis, endocytosis, sodium-potassium pump |
Different types of Passive Transport are – Osmosis, diffusion, and facilitated diffusion |
Active Transport
This is the biological process in which molecules move against the concentration gradient and require chemical energy to move biochemical compounds from a lower region to the high region. Therefore, this process uses ATP – Adenosine triphosphate to pump molecules through a concentration gradient. Complex sugar, ions, large cells, proteins, and other particles are transported in this process. There are two types of Active transport:
- Primary Active transport
- Secondary Active transport
Exocytosis, endocytosis and sodium-potassium pump are a few examples of active transport. The process of endocytosis and exocytosis are utilized by all the cells for transportation of molecules which cannot passively permeate via the membrane.
- Endocytosis is the process of active transportation of molecules into the cells by the action of engulfing it along with its membrane.
- Exocytosis produces a counter function thereby forcing molecules out of the cell. The process of homeostasis facilitates an equal flow of molecules in and out of a cell which confers that the number of molecules that enter the cell through endocytosis equates to the number of molecules that exits a cell through the process of exocytosis. Both the processes assure that nutrients and wastes are balanced for the smooth functioning of the cells.
Passive Transport
In these biological process, there is no need for any energy for transporting the molecules, as the biochemicals move from higher to the lower concentration. All the easy soluble particles are transported through passive transport. This process is carried out to maintain the balance and the equilibrium level in a cell. All the wastes molecules including, water and carbon dioxide is separated and moved out of the cell using passive transport. Meanwhile, nutrients like oxygen that are functional for the cell are diffused in this process. Osmosis, diffusion and facilitated diffusion are some of the examples of passive transport.
Key Points on Active and Passive Transport
- Active transport requires energy for the movement of molecules whereas passive transport does not require energy for the movement of molecules.
- In the active transport the molecules move against the concentration gradient whereas in the passive transport the molecules move along the concentration gradient.
- Uptake of glucose in the human intestine is an example of active transport.
- Simple diffusion, facilitated diffusion, osmosis and filtration are examples of passive transport.
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Frequently Asked Questions
How is active transport different from passive transport?
Active transport moves molecules and ions from lower concentration to higher concentration with the help of energy in the form of ATP. On the other hand, passive transport moves molecules and ions from a higher concentration to lower concentration without any energy.
What is the role of ATP in active transport?
ATP hydrolysis provides energy for the movement of molecules and ions across a concentration gradient. The movement of molecules occurs either inside the cells (endocytosis) or out of the cells (exocytosis).
Mention two examples of active and passive transport.
Examples of active transport include sodium-potassium pump, uptake of mineral ions by the roots of the plants, etc. Whereas, the examples of passive transport include the exchange of gases in the alveoli of the lungs and the exchange of nutrients in the kidneys.
What is the importance of active and passive transport?
Active and passive transport regulates the entry and exit of ions and molecules in a cell. These processes allow only specific materials to cross spontaneously through the cell membrane. Rest need a carrier to pass through the membrane.
What are the different types of passive transport?
Passive transport can be of the following different types:
- Simple diffusion
- Osmosis
- Facilitated diffusion