User:Le Van Luong/sandbox

Every organism is required energy to be active^[3]. However, to obtain the energy from outside the cell, all molecules have to be broken down^[3]. This process is called Intracellular Digestion^[3]. In its broadest sense, intracellular digestion is the breakdown of substances within the cytoplasm of a cell. In detail, phagocytosis’s duty is obtaining the food particles and digest in vacuole^[1]. For example, following phagocytosis, the ingested particle (or pagosome) fuses with a lysosome containing hydrolytic enzymes to form a phagolysosome; the pathogens or food particles within the phagosome are then digested by the lysosome's enzymes.

Intracellular digestion can also refer to the process in which animals that lack a digestive tract bring food items into the cell for the purposes of digestion for nutritional needs. This kind of intracellular digestion occurs in many unicellular protozoans, in Pycnogonida, in some molluscs, Cnidaria and Porifera. There is another type of digestion, called extracellular digestion. In amphioxus, digestion is both extracellular and intracellular

Function

Intracellular digestion is divided into heterophagic digestion and autophagic digestion^[2]. These two types take place in Lysosome and they have very specific function^[2]. Heterophagic intracellular digestion has an important job which breaks down all molecules that is brought into a cell by endocytosis^[2]. The broken molecules are needed to reach cytoplasm, however, it will never happen if the molecules are not hydrolyzed in the lysosome^[2]. Autophagic intracellular digestion is processed in the cell, which means it digest the internal molecules^[2].

References

1 Roberts, M. B. V. Biology: A Functional Approach. Nelson Thornes. ISBN 9780174480198.

2 Jamieson, G. A.; Robinson, D. M. Mammalian Cell Membranes: Volume 2: The Diversity of Membranes. Elsevier. ISBN 9781483162782.

3 Anderson, O. Roger (1 January 1970). "Intracellular Digestion". The American Biology Teacher. 32 (8): 461–467. doi:10.2307/4443206.

4 Glick, Danielle; Barth, Sandra; Macleod, Kay F. (21 November 2016). "Autophagy: cellular and molecular mechanisms". The Journal of pathology. 221 (1): 3–12. doi:10.1002/path.2697. ISSN 0022-3417.

5 Mizushima, Noboru (15 November 2007). "Autophagy: process and function". Genes & Development. 21(22): 2861–2873. doi:10.1101/gad.1599207. ISSN 0890-9369.