There are two essential forms of endocytosis: Pinocytosis and Receptor-Mediated Endocytosis. Pinocytosis is different, and it is not like receptor-mediated endocytosis, as pinocytosis is non-specific when it comes to substances that they transport.
The water absorption in pinocytosis takes place in small quantities than in receptor-mediated endocytosis, which will take water in large quantities.
Key Takeaways
- Pinocytosis is the process by which cells ingest small amounts of fluid and dissolved substances through small vesicles.
- Receptor-mediated endocytosis selectively transports specific molecules into cells using receptor proteins on the cell membrane.
- Pinocytosis is a non-specific form, whereas receptor-mediated endocytosis is a highly selective process.
Pinocytosis vs Receptor-Mediated Endocytosis
The difference between Pinocytosis and Receptor-Mediated Endocytosis is in pinocytosis. The liquid will be ingested into the cell. In receptor-mediated endocytosis, the specific molecules will be ingested into the cell. The major difference is pinocytosis does not use selection, but receptor-mediated endocytosis uses selection. The efficiency of pinocytosis is less. However, the efficiency of receptor-mediated endocytosis is more.
Pinocytosis is called the ingestion of surrounding fluids. It is an active transport that plays a vital role in cellular processes such as waste materials excretion, uptaking of nutrients, and signal transduction.
It plays an important role for higher organisms in transporting fats and vitamins in dissolved molecules. It is mostly seen in unicellular organisms like the amoeba, which use it for uptaking water and dissolving nutrients.
Receptor-mediated endocytosis is related to cholesterol as the cells in them will be taken up in the blood. It is one of the essential components of all cell membranes.
The regulatory molecules in receptor-mediated endocytosis will bind to plasma membrane receptors targeting the cells. They use the same membranes for processing. Here, only specific molecules are ingested into the cell.
Comparison Table
| Parameters of Comparison | Pinocytosis | Receptor-Mediated Endocytosis |
|---|---|---|
| Process | It is not a selective process. | It is a selective process. |
| Process efficiency | It is less efficient. | It requires more efficiency. |
| Receptors | It does not involve receptors. | It uses receptors on the cell membrane. |
| Uptakes | Liquid | Solutes |
| Also called as | Cell drinking | Clathrin-mediated endocytosis |
What is Pinocytosis?
It is a process by which liquid droplets ingest the living cells. It is a type that comes under endocytosis. In endocytosis, the cellular substances are brought inside the cell.
In pinocytosis, the cell membrane folds small packets and then captures the dissolved substances and cellular fluids. In pharmacology, the particles or fluid will be engulfed by the cell. Pinocytosis is otherwise called Fluid Endocytosis.
In pinocytosis, an individual droplet of liquid will passively travel through the cell membrane. Then the droplet will be either absorbed or bound on the cell membrane. In most cells, it is formed as a continuous process.
It is a non-specific way of internalizing dissolved nutrients. The process will be initiated with the help of the desired molecule in the extracellular fluid. The molecules can be of any form, such as proteins, sugars, ions, etc.
It differs from other receptor-mediated endocytosis as it is not specific to one molecule. Pinocytosis is divided into two types called macropinocytosis and micropinocytosis.
In macropinocytosis, the molecules are larger. In micropinocytosis, the molecules are smaller in size. They are divided based on molecule size.
Because of its non-specific absorption of molecules, a large number of different molecules will be transported at the same time.
What is Receptor-Mediated Endocytosis?
It is a form of endocytosis. It uptakes only solutes in the cells. One example of receptor-mediated endocytosis is importing iron into a mammalian cell.
Because iron has serum cholesterol which will not allow it to import by itself, the viruses in receptor-mediated endocytosis are well established because the internalization of viruses is only dependent on virus-specific surface cellular receptors.
Also, the virus will attack the cells which display the specific receptors. With the help of receptors, they bind specific ligands. And these ligands are coated pits to form endosomes. It is active.
It has a mechanism for the selective uptake of specific macromolecules. All mammalian cells carry out receptor-mediated endocytosis at some level.
Phagocytosis is formed from receptor-mediated endocytosis. Clathrin is involved in three receptor-mediated intracellular transport pathways.
Some risks may develop in receptor-mediated endocytosis, leading to proteinuria and substance loss. It is one of the important signs of kidney disease.
This will lead to cardiovascular disease as well. One of the advantages of receptor-mediated endocytosis is that it allows macromolecules to enter the cells needed for cellular function.
Their mode of picking up the particles also varies in the extracellular space.
Main Differences Between Pinocytosis and Receptor-Mediated Endocytosis
- When it comes to process, pinocytosis is not selective. On the other hand, the process involved in receptor-mediated endocytosis is selective.
- The process efficiency of pinocytosis is less efficient. On the other hand, the process efficiency of receptor-mediated endocytosis requires more efficiency.
- Pinocytosis does not use receptors. On the other hand, receptor-mediated endocytosis uses receptors that are available in the cell membrane.
- Pinocytosis uptakes liquid. On the other hand, receptor-mediated endocytosis uptakes solutes.
- Pinocytosis is also called cell drinking. On the other hand, the other name for receptor-mediated endocytosis is Clathrin-mediated endocytosis.
- In pinocytosis, solutes in the extracellular fluid go into cells. On the other hand, in receptor-mediated endocytosis, the solutes will bind to the cell.
Last Updated : 28 June, 2023
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Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.
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