bacteria

Table of Contents

Introduction
The bacterial cell
- Bacteria as prokaryotes
- Diversity of structure of bacteria
- Morphological features of bacteria
  - The Gram stain
  - The cell envelope
  - Capsules and slime layers
  - Flagella, fimbriae, and pili
  - The cytoplasm
    - Genetic content
    - Cytoplasmic structures
- Biotypes of bacteria
Bacterial reproduction
- Reproductive processes
  - Binary fission
  - Budding
  - Sporulation
- Exchange of genetic information
- Growth of bacterial populations
Ecology of bacteria
- Distribution in nature
- The importance of bacteria to humans
  - Bacteria in food
  - Bacteria in industry
  - Bacteria in medicine
Evolution of bacteria
Biosynthesis, nutrition, and growth of bacteria
- Factors affecting bacterial growth
  - Nutritional requirements
  - Physical requirements
    - Oxygen
    - Temperature
    - pH
    - Salt and water
- Bacterial metabolism
  - Heterotrophic metabolism
  - Autotrophic metabolism
  - Phototrophic metabolism
- Biosynthetic pathways of bacteria
Classification of bacteria
- Taxonomic rankings
- The bacterial species problem
- Genetic approaches
  - DNA-based methods
  - 16S rRNA analysis
- Classification by morphology, biochemistry, and other features

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bacteria: Facts & Related Content

Written and fact-checked by The Information Architects of Encyclopaedia Britannica

Last Updated: Jun 13, 2025

News •

Energy drain from antibiotics spurs bacteria to resist treatment faster • June 9, 2025, 11:03 PM ET (News-Medical)

Banning fluoride could cause widespread dental disease in children • May 30, 2025, 2:28 PM ET (News-Medical)

Mysterious bacteria found on Chinese space station has never been seen before • May 24, 2025, 5:58 AM ET (Earth.com)

New species of space-adapted bacteria discovered on China's Tiangong space station • May 21, 2025, 9:39 AM ET (Space)

Facts

Also Known As	Schizophyta • bacterium

Photos and Videos

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spirillum phytoplasma methanogenic bacterium mycoplasma-like organism free-living bacterium mutualistic bacterium Pasteuria Xylella bacillus Gram-negative bacterium fungus virus archaea parasitism prion viroid plant animal biology taxonomy

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Key People

Joshua Lederberg, 1958.

Joshua Lederberg

American geneticist

Robert Koch.

Robert Koch

German bacteriologist

Antonie van Leeuwenhoek

Antonie van Leeuwenhoek

Dutch scientist

Ferdinand Cohn

Ferdinand Cohn

German botanist

Frances Arnold

American chemical engineer

George P. Smith

American biochemist

Edward L. Tatum

American biochemist

François Jacob, 1965.

François Jacob

French biologist

René Dubos

American microbiologist

Robert Huber

German biochemist

David Hendricks Bergey

American bacteriologist

Johann Deisenhofer

German American biochemist

Hans Buchner

German bacteriologist

Hartmut Michel

German biochemist

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