Question

(1). Difference b/w ENDOCYTOSIS and EXOCYTOSIS.

(2). What are the types of ENDOCYTOSIS ????¿¿

Answer 1

In exocytosis, a cell expels molecules and other contents that are too large to pass through the cell membrane structure. This discharge is accompanied by the fusion of the vesicular membrane and the plasma membrane. This process is carried out in three ways that separately involve the molecular constituents like endosomes, lysosomes, exosomes, neurotransmitters, etc.

In endocytosis, the body cells ingest various molecules such as proteins, polar molecules, and other substances, through their hydrophobic plasma membrane. This process is carried out by many eukaryotic cells to ingest food particles by surrounding them, and in this case, the plasma membrane is extended outwards. The basic mechanism of both the processes of exocytosis and endocytosis, is more or less the same. Vesicles are the structures used for the transportation of molecules. They are also used for storage and transportation of food. Also, many bacteria and pathogens may enter the body by this process. These structures may have a completely different internal composition as compared to that of the body cells.

Answer 2

(1) Following are the points to show difference between Endocytosis and Exocytosis.

1. Endocytosis is involved in the up taking of the substance from external environment while the Exocytosis is involved in the elimination of waste and secretion of content in Golgi into the external environment.
2. Endocytosis occurs by both phagocytosis and pinocytosis while the Exocytosis  occur  by constitutive and regulated secretory pathway .
3. Internal vesicles like phagosomes are formed in Endocytosis while secretory vesicles are formed in Exocytosis.

(2) There are two major types of Endocytosis :

1. Pinocytosis
2. Phagocytosis.