May eukaryotic cells live without a nucleus

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Prokaryotes and eukaryotes

All living things belong either to the prokaryotes or the eukaryotes. This classification is based on the presence of a real cell nucleus, which is not covered by a membrane. The nucleus contains the genetic material, the DNA, while cells without a nucleus contain the DNA freely in the cytoplasm. Bacteria (eubacteria) and archaea belong to the nucleus-less prokaryotes, while animals, plants and fungi are counted among the eukaryotes.

Pro- and eukaryotes differ not only with regard to the cell nucleus, but also in many other properties with regard to cell structure and metabolism. These differences indicate that prokaryotes and eukaryotes separated very early in evolution about 3.2 billion years ago. Today scientists assume that the more complex eukaryotes arose from the merging of different unicellular organisms, so to speak through a process in which one unicellular organism has taken in another unicellular organism as a "pet" (endosymbiosis).

Pro- and eukaryotes share the same basic abilities and characteristics that are considered to be general hallmarks of life on earth:

  • Multiplication by division; this also applies to the inheritance of DNA from the mother to a daughter cell. The DNA double strand is first divided and then added to the double strand again in the daughter cells (replication). Errors can also occur during this process (mutations), which lead to changed offspring.
  • Metabolism, i.e. the cells absorb substances from their environment, convert them into new components or usable energy and excrete products that are not usable or dangerous for the organism.
  • The information for the construction plan is stored in the form of DNA. This DNA is rewritten into messenger molecules (transcription) and then translated into proteins (translation).
  • Even the most primitive cells react to the environment or conditions within the organism, so they are irritable or excitable.
  • After all, death is also a property of living systems, because no individual living being is immortal.

While a single cell fulfills all tasks in a single cell, there are many differently differentiated cell types in a multicellular organism, each of which can only perform certain tasks.

example

Here are a few figures: the human body consists of around 220 different cell types that make up the different types of tissue. The cell size of eukaryotic cells is on average 10-100 μm (1 μm is 0.000.001 m, one millionth of a meter). The sum of all cells in humans exceeds the number.