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Bacteria & Viruses

Bacteria & Viruses. Chapter 19. Eubacteria. Are prokaryotes – have no membrane bound nucleus The larger of the 2 kingdoms Live almost everywhere Fresh water, salt water, land, inside the human body Eubacteria are usually surrounded by a cell of peptidoglycan. Archaebacteria.

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Bacteria & Viruses

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  1. Bacteria & Viruses Chapter 19

  2. Eubacteria • Are prokaryotes – have no membrane bound nucleus • The larger of the 2 kingdoms • Live almost everywhere • Fresh water, salt water, land, inside the human body • Eubacteria are usually surrounded by a cell of peptidoglycan

  3. Archaebacteria • lack the peptidoglycan of eubacteria • have different membrane lipids • The DNA sequences of key archaebacterial genes are more like eukaryotes • Live in extremely harsh environments

  4. Archaebacteria • Methanogens live in oxygen-free environments, such as thick mud and the digestive tracts of animals. • Others live in salt lakes and hot springs

  5. Shapes • Bacilli – Rod shaped • Cocci – Spherical • Spirilla – Spiral / Corkscrew

  6. Movement • Some prokaryotes do not move at all. Others are propelled by flagella, whiplike structures used for movement. Other prokaryotes lash, snake, or spiral forward. Still others glide slowly along a layer of slimelike material they secrete. • Cilia = hair-like structure for moving.

  7. Metabolic Diversity • Heterotrophs – need to find their own food • Chemoheterotrophs = get energy and carbon from organic molecules • Photoheterotrophs = Use sunlight for food, but also need organic compounds for carbon • Autotrophs • Photoautotrophs = use sunlight. Like green plants • Chemoautotrophs = use chemical reactions from sulfide, nitrites, sulfur or iron.

  8. Metabolic Diversity • Obligate aerobes = need oxygen • Obligate anaerobes = must live without oxygen. • Facultative anaerobes = can live in either.

  9. Growth & Reproduction • Binary Fission - Grows 2x the size, copies DNA and divides. Asexual reproduction.

  10. Growth & Reproduction • Conjugation – Exchange genetic info thru a hollow tube

  11. Growth & Reproduction • Spore formation – formed by bacteria. • Forms inside of bacteria and released when conditions are right. • Allows bacteria to reproduce under harsh conditions

  12. Importance • Decomposers • Break down dead matter and help recycle nutrients, maintaining equilibrium in the environment. • Help in sewage treatment. • Nitrogen Fixers • Bacteria help transform nitrogen gas into a form they can use. • Human Uses • Clean up oil spills, digestion, medicines

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