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Evaluation of Article "Regeneration"

There is overall a disproportionate amount of focus on regeneration in animals rather than unicellular or simple multicellular organisms given the generality of the title "Regeneration." Section on Amphibians could be split into two subcategories, newts and salamanders, since both have distinct mechanisms for regeneration. Various animals are discussed, however, to give a thorough evaluation of the degrees of regenerative abilities in other species. The explanations of regenerative processes does not go too specific into the intermolecular or intercellular interactions that underlie regeneration and focuses on the general processes to help the online public audience to better understand the article.

The sources of the article are legitimate and reliable, and they are used throughout each section. There are also no warning banners above the Wikipedia page. The lead article provides a neutral description of the state of regenerative biology in various species using proper citations. Few jargons that were used were linked to other Wikipedia articles that explain this term.

Endosymbiosis of Protomitochondria

Diagram of eukaryotic cell (animal)

Endosymbiosis, a historically controversial theory, explains how some organelles with likeness to individual cells were derived.

Mitochondria

Mitochondria of a mammal lung cell visualized using Transmission Electron Microscopy

Mitochondria is an organelle that synthesizes ATP for the cell by metabolizing carbon-based macromolecules. Endosymbiotic theory suggests that the proto-eukaryote engulfed a protomitochondria, and this endosymbiont became an organelle. The presence of deoxyribonucleic acid (DNA) in mitochondria and proteins derived from this genetic material suggest that this organelle may have been a prokaryote prior to its integration into the proto-eukaryote. Mitochondria are regarded as organelles rather than endosymbionts because mitochondria and the host cells share some parts of their genome, undergo mitosis simultaneously, and provide each other means to produce energy. Endomembrane system and nuclear membrane were derived from the protomitochondria.

Nuclear Membrane

Diagram of a nuclear membrane

The presence of a nucleus is one major difference between eukaryotes and prokaryotes. Some conserved nuclear proteins between eukaryotes and prokaryotes suggest that these two types had a common ancestor. Another theory behind nucleation is that early nuclear membrane proteins caused the cell membrane to fold inwardly and form a sphere with pores like the nuclear envelope.

Strictly regarding energy expenditure, endosymbiosis would save the cell more energy to develop a nuclear membrane than if the cell was to fold its cell membrane to develop this structure since the interactions between proteins are usually enabled by ATP.  Digesting engulfed cells without a complex metabolic system that produces massive amounts of energy like mitochondria would have been challenging for the host cell. This theory suggests that the vesicles leaving the protomitochondria may have formed the nuclear envelope.  

Endomembrane system

Diagram of endomembrane system in eukaryotic cell

Modern eukaryotic cells use the endomembrane system to transport products and wastes in, within, and out of cells. The membrane of nuclear envelope and endomembrane vesicles are composed of similar proteins as are the endomembrane vesicles with their source and destination organelle. This suggests that what formed the nuclear membrane also formed the nuclear membrane.

Prokaryotes do not have a complex internal membrane network like the modern eukaryotes, but the prokaryotes could produce extracellular vesicles from their outer membrane. After the early prokaryote was consumed by a proto-eukaryote, the prokaryote would have continued to produce vesicles that accumulated within the cell. Interaction of internal components of vesicles may have led to formation of the endoplasmic reticulum and contributed to the formation of Golgi apparatus.