Summary
Single-celled prokaryotes found everywhere, vital for nutrient cycling, digestion and some disease.
In depth
Bacteria are about 1 to 10 micrometres long. Most have a peptidoglycan cell wall and a single circular chromosome. They have varied metabolism: photosynthetic, chemosynthetic or heterotrophic; aerobic or anaerobic.
Bacteria are used in food (yoghurt), medicine (antibiotic production) and biotechnology, but also cause diseases such as cholera and tuberculosis.
Bacteria carry out nitrogen fixation, decomposition and photosynthesis. Doubling time varies from minutes to days. Some form spores, others biofilms.
Example: lactic acid bacteria ferment milk.
Frequently asked questions
What is Bacteria?
Single-celled prokaryotes found everywhere, vital for nutrient cycling, digestion and some disease.
Which area of biology covers Bacteria, and how advanced is it?
Bacteria is one of the 54 topics in Microbiology. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Microorganisms, Protists, Archaea.
Can you give an example of Bacteria?
E. coli is a standard model organism.
What should I learn before Bacteria?
Bacteria is a Beginner topic, so no earlier topic is required. Other Beginner topics in Microbiology that pair well with it include Microorganisms, Archaea, Bacterial Shapes.
What topics are related to Bacteria?
The closest topics to Bacteria are Microorganisms, Protists, Archaea, Yeast. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Bacteria?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Bacteria. To practise the whole of Microbiology, use the Microbiology quiz.
How is Bacteria different from Microorganisms?
Bacteria: Single-celled prokaryotes found everywhere, vital for nutrient cycling, digestion and some disease. Microorganisms: Living things too small to see without a microscope, including bacteria, archaea, protists, fungi and microscopic algae. Read both side by side and note what each one explains.
How should I study Bacteria 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 Microorganisms and explain the difference aloud. Finally, take the Microbiology quiz and come back to this page for any question you miss.