Two basic kinds of cells
Every living thing is made of cells, and all cells fall into two groups. Prokaryotic cells, which make up bacteria and archaea, have no nucleus. Eukaryotic cells, which make up animals, plants, fungi and protists, keep their DNA inside a nucleus. The animal and plant cells on this site’s diagrams are both eukaryotic.
What every cell has
All cells, prokaryotic or eukaryotic, have a cell membrane around them, cytoplasm inside, DNA as their genetic material, and ribosomes to build proteins. These four features are the minimum a cell needs to stay alive and make copies of itself.
What makes a prokaryote different
A prokaryote’s DNA sits in a region called the nucleoid, with no membrane around it. Prokaryotes have no mitochondria, endoplasmic reticulum or Golgi apparatus. Most have a cell wall, and many have extra features such as a capsule, a flagellum for swimming, or small hair-like pili. According to OpenStax, prokaryotic cells are usually 0.1 to 5.0 micrometers across, while eukaryotic cells range from about 10 to 100 micrometers.
- No nucleus: DNA is in the nucleoid.
- No membrane-bound organelles.
- Much smaller than most eukaryotic cells.
What makes a eukaryote different
Eukaryotic cells divide their work among membrane-bound organelles: the nucleus, the endoplasmic reticulum, the Golgi apparatus, mitochondria and, in plants, chloroplasts. This separation lets one cell carry out many different chemical reactions at once without them interfering with each other.
Quick way to remember
“Pro” sounds like “no”: prokaryotes have no nucleus. “Eu” sounds like “do”: eukaryotes do. Bacteria are prokaryotes; you, a tree and a mushroom are made of eukaryotic cells.
Sources and further reading
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