Phagocytosis means “cellular eating” while Pinocytosis means “cellular drinking”. Pinocytosis and Phagocytosis are the two categories of Endocytosis. Both are the active process and requires energy (ATP) as adenosine triphosphate for the uptake of materials. Phagocytosis is an intake of solid particles with the formation of vesicles called phagosomes, while pinocytosis is the intake of liquid particles with the formation of vesicles called pinosomes.
The term ‘Endocytosis’ was given by Christain de Duve in the year 1963. Both the terms refers to the intake of material through the plasma membrane by forming vesicles which are a membrane-bound droplet located inside the cytoplasm of the cell. Endocytosis occurs in the animal cell and very rarely in plant cell as the plant cell is surrounded by the cell wall, which causes hindrance in the invagination of the plasma membrane.
Exocytosis is just opposite process to that of endocytosis in which substances are being allowed to move out of the cell, by a similar mechanism to that of endocytosis and is common in secretory cells. In both cases, endosomes are formed, which is an invagination of the plasma membrane to form vesicles. These vesicles locate the engulfed particles which can be solid or liquid.
Content: Pinocytosis Vs Phagocytosis
|Basis for Comparison||Pinocytosis||Phagocytosis|
|Meaning||Pinocytosis is called cell drinking, substance is directly ingested as it is in dissolved form and ready for cellular absorption.||Phagocytosis is called cell eating, in which particles are broken down into simpler substance with the help of enzymes for absorption.|
|Process of engulfing||By Invagination.||By pseudopodia (false feet).|
|Kind of particles ingested||Liquid.||Solid.|
|Substrate specific||Pinocytosis is not substrate specific and cell takes all kind of surrounding fluids with all solutes present.||Phagocytosis is specific in substrate it transport.|
|Purpose||Pinocytosis is used for intake of materials.||Phagocytosis is used for defensive purpose by engulfing the foreign particles.|
|Role of Lysosomes||No role of lysosomes.||Lysosomes combine with phagosomes for the formation of food vacuole.|
|Types of particles intake||Sugars, ions, amino acids, enzymes, hormones, etc.||Foreign particles, harmful bacteria and virus, dust, etc.|
|Where it happens||Pinocytosis usually occurs in secretory cells, cell linings of blood capillaries.||Phagocytosis is performmed by neutrophills, macrophages and protozoans.
Cell drinking is the another name of Pinocytosis. It is the intake of liquid and small particles. Usually, ions, amino acids, sugars, insulin, and lipoproteins are ingested through this method.
Process– In this the small liquid particles which are to be engulfed get themselves attached to the outer layer of the plasma membrane. These small particles attach to the specific receptors located on the outer layer plasma membrane. Subsequently, plasma membranes form the membrane-bounded vesicles called pinosomes, which is an invaginated area surrounding the particles. These pinosomes finally travel to the cytoplasm and the particles are released.
Definition of Phagocytosis
Cell eating is also called Phagocytosis. Here the particles which are to be ingested are larger in size, hence digestive enzymes are required.
Process– Plasma membrane surrounds and fuses with the particles to be engulfed, where phagocytic vesicles are formed called as phagosomes. These phagosomes along with the lysosomes release digestive enzymes which are helpful in digesting the phagosomes.
Phagocytosis is most commonly seen in protozoan, amoeba, and in higher animals, including humans, this process helps in engulfing foreign particles, harmful bacteria, virus, and other waste materials.
Key Differences Between Pinocytosis and Phagocytosis
We already discuss, that both the mechanisms pinocytosis and phagocytosis falls under the main process called Endocytosis, given below are the key differences between them:
- Pinocytosis is the process of ingestion of small liquid particles through plasma membrane with the help of formation of vesicles known as pinosomes; Phagocytosis is the process of ingestion of solid particles through plasma membrane with the help of lysosomes and phagosomes, which release enzymes for breaking the larger particles.
- The process of engulfing is by Invagination in pinocytosis, and by pseudopodia in phagocytosis.
- Lysosomes do not play any role in pinocytosis, while lysosomes along with phagosomes help in digestion of bigger particles.
- Pinocytosis is not substrate specific and cell takes all kind of surrounding fluids with all solutes present while, Phagocytosis is specific in substrate transportation.
- The purpose of pinocytosis is used for intake of materials, whereas phagocytosis is used for the defensive purpose by engulfing the foreign particles. The vesicles formed in pinocytosis is pinosomes and that of phagocytosis is known as phagosomes.
- The particles taken in pinocytosis are enzymes, hormones, amino acids, sugars, etc. for the purpose of intake of smaller particles; while phagocytosis is performed by neutrophils, macrophages, and protozoans for defensive purpose and ingests dust, foreign particles, harmful bacteria, and virus.
Cells are considered as a basic unit of life and are well known for sustaining it well. From the unicellular organisms to the multicellular organisms, follows the somehow similar process, they carry almost same biochemical reactions. One of them is Endocytosis, where engulfing of material whether it is a solid or liquid takes place inside the cell through the plasma membrane.
Pinocytosis and Phagocytosis are the two categories of the above process. Earlier one helps in ingesting liquid and smaller particles while the latter one helps in engulfing solid particles. Exocytosis is the opposite of process to that of endocytosis, where instead of engulfing, cell helps in moving out the particles by almost similar processes like pinocytosis and phagocytosis.