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What Are the Differences between Prokaryotic and Eukaryotic Cells?

Mark Wollacott
Mark Wollacott

Prokaryotic and eukaryotic cells are the two basic forms cells can take. Prokaryotic cells form single-cell organisms such as bacteria and archaea, while eukaryotic cells are the basis of all other types of life. In terms of the evolution of the Earth, prokaryotic cells came first and were later superseded by their eukaryotic counterparts.

The most noticeable difference between prokaryotic and eukaryotic cells cells is the latter’s ability to form a complex organism. Prokaryotes are all single-cell organisms while eukaryotes include plants, fungi, and animals. The ability to combine and cooperate has allowed eukaryotes to develop far beyond prokaryotes.

Prokaryotic cells are more primitive than eukaryotic cells.
Prokaryotic cells are more primitive than eukaryotic cells.

Both cell types contain elements similar to one another. Both types are deoxyribonucleic acid (DNA) based organisms containing a cell membrane, flagellum, cytoplasm, and ribosomes. They share the same kind of DNA and the same kind of genetic code. One difference is that a prokaryote’s DNA is circular while a eukaryote’s is linear. Eukaryotic DNA binds with histone proteins to form chromosomes, while prokaryotic DNA does not.

Singled-celled archaea are prokaryotes.
Singled-celled archaea are prokaryotes.

The most notable physiological difference between prokaryotic and eukaryotic cells is the former’s lack of a true nucleus. A nucleus contains and processes the majority of the eukaryotic cell’s DNA, and its function is to control cellular activity. The nucleus is contained within a membrane to keep it separate from the rest of the cell. The prokaryote has a nucleoid center where DNA is gathered, but there is no separating membrane.

Plant cells have organelles called plastids.
Plant cells have organelles called plastids.

Internal membranes are a recurring difference between the two cell types. A eukaryotic cell is filled with distinct miniature organs called organelles. These membrane-bound elements perform specific functions within the cell and are distinct from the cell’s cytoplasm. Prokaryotes tend to have no organelles separated from the cytoplasm. Cytoplasm is a viscous liquid contained within a cell.

In eukaryotic cells, the nucleus contains and processes the majority of the cell's DNA.
In eukaryotic cells, the nucleus contains and processes the majority of the cell's DNA.

While both prokaryotic and eukaryotic cells have ribosomes, the ribosomes in eukaryotic cells are larger and more developed. Ribosomes use amino acids and ribonucleic acid (RNA) to create proteins within the cell. A prokaryotic ribosome is made up of three kinds of ribosomal RNA (rRNA) and about 50 types of protein. The eukaryotic ribosome, however, consists of five types of rRNA and around 80 types of protein.

Eukaryotic cells contain a distinct organelle called a mitochondrion, and plant cells also have organelles called plastids. Prokaryotic cells have neither. Mitochondria and plastids seem to have a common origin. Both appear to have been distinct prokaryotes absorbed within eukaryotes in a permanent symbiotic relationship.

Some generalized differences are complicated by exclusions. As a general rule, these cells differ over cell walls. While all prokaryotes have them and most eukaryotes do not, there are exceptions. Some prokaryotes have developed primitive organelles, but generally, they are absent.

Discussion Comments

Talentryto

I remember in college biology we had to compare and contrast prokaryotic and eukaryotic cells. It was always very confusing to me. This article is very easy to understand and explains this biology topic very well. Wish I had read it when I was taking exams in biology class!

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    • Prokaryotic cells are more primitive than eukaryotic cells.
      By: Mark Rasmussen
      Prokaryotic cells are more primitive than eukaryotic cells.
    • Singled-celled archaea are prokaryotes.
      By: Alila Medical Media
      Singled-celled archaea are prokaryotes.
    • Plant cells have organelles called plastids.
      By: snapgalleria
      Plant cells have organelles called plastids.
    • In eukaryotic cells, the nucleus contains and processes the majority of the cell's DNA.
      By: jscreationzs
      In eukaryotic cells, the nucleus contains and processes the majority of the cell's DNA.