Summary
A simple cell with no membrane-bound nucleus; its DNA lies in a nucleoid region, as in bacteria and archaea.
In depth
Prokaryotes (bacteria and archaea) are typically 0.5 to 5 micrometres across. Their DNA is usually one circular chromosome in the nucleoid, with no membrane around it, and they carry 70S ribosomes. Most have a cell wall, and many have flagella, pili, a capsule and small plasmids.
They divide by binary fission, which is fast: E. coli can double every 20 minutes under good conditions. Lacking membrane-bound organelles, many reactions occur at the plasma membrane, which in respiring bacteria hosts the electron transport chain.
Metabolic variety is the real strength of prokaryotes. Between them they can use light, inorganic chemicals (chemolithotrophy), sugars or even methane as energy sources, and they colonise boiling springs, ice and deep rock. A typical bacterial genome has 1 to 10 million base pairs with few introns, and genes for related functions are often grouped into operons.
Gram-positive bacteria have a thick peptidoglycan wall that holds crystal violet stain; Gram-negative ones have a thin wall plus an outer membrane that makes them more resistant to many antibiotics. Some form endospores that survive heat, drying and radiation.
Common mistake: calling prokaryotes "primitive". They have evolved for around 3.5 billion years and are extremely well adapted.
Frequently asked questions
What is Prokaryotic Cell?
A simple cell with no membrane-bound nucleus; its DNA lies in a nucleoid region, as in bacteria and archaea.
Which area of biology covers Prokaryotic Cell, and how advanced is it?
Prokaryotic Cell is one of the 52 topics in Cell Biology. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Eukaryotic Cell, Chloroplast, Endosymbiotic Theory.
Can you give an example of Prokaryotic Cell?
Cyanobacteria carry out photosynthesis on internal thylakoid-like membranes without any chloroplast.
What should I learn before Prokaryotic Cell?
Prokaryotic Cell is a Beginner topic, so no earlier topic is required. Other Beginner topics in Cell Biology that pair well with it include Cell Theory, Eukaryotic Cell, Plasma Membrane.
What topics are related to Prokaryotic Cell?
The closest topics to Prokaryotic Cell are Eukaryotic Cell, Chloroplast, Endosymbiotic Theory, Mitochondrion. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Prokaryotic Cell?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Prokaryotic Cell. To practise the whole of Cell Biology, use the Cell Biology quiz.
How is Prokaryotic Cell different from Eukaryotic Cell?
Prokaryotic Cell: A simple cell with no membrane-bound nucleus; its DNA lies in a nucleoid region, as in bacteria and archaea. Eukaryotic Cell: A complex cell with a true nucleus and membrane-bound organelles, found in animals, plants, fungi and protists. Read both side by side and note what each one explains.
What is a common mistake about Prokaryotic Cell?
Calling prokaryotes "primitive". They have evolved for around 3.5 billion years and are extremely well adapted.
How should I study Prokaryotic Cell step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Eukaryotic Cell and explain the difference aloud. Finally, take the Cell Biology quiz and come back to this page for any question you miss.