Download Prokaryotes: Size, Shape, and Movement

Prokaryotes
Learning Objectives
 Explain how prokaryotes are classified.
 Describe how prokaryotes vary in structure and function.
 Explain the role of prokaryotes in the living world.
Classifying Prokaryotes
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Unicellular
No nucleus
DNA in cytoplasm
Bacteria or Archaea
Bacteria
Bacteria include a wide range of organisms; many phyla are
needed to classify this group.
Archaea vs. Bacteria
Important differences:
• Cell walls
• Cell membranes
• DNA sequences
• Harsh environments
Prokaryotes: Size, Shape, and Movement
Prokaryotes vary in size, shape, and movement.
Bacilli
• None
• Propelled by flagella
• Glide on secretions
Cocci
Spirilla
Prokaryotes: Nutrition and Metabolism
Prokaryotes: Nutrition and Metabolism
Prokaryotes: Reproduction and Change
Prokaryotes reproduce using binary fission.
conjugation
endospore
Decomposers
By assisting in breaking down dead organisms, prokaryotes
supply raw materials in the environment.
Bacteria of the
genus Rhizobium
Cyanobacteria of the
genus Anabaena
Bacteria called
actinomycetes
Producers
Food chains everywhere are dependent upon prokaryotes as
producers of food and biomass.
Nitrogen Fixers
Nitrogen-fixing bacteria
and archaea provide 90%
of atmospheric nitrogen.
Prokaryotes Overview
Classification:
• Bacteria
• Archaea
• Diverse
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Size
Shape
Movement
Metabolism
Ecologically important