Bacteria

Bacterial ClassificationBacteria Eubacteria Live in soil Live in organisms – Cause disease Found everywhere Archaebacteria Ancestors of eukaryotic cells Found in harsh env. Two divisions

Eubacteria and Archaebacteria: The Prokaryotic Kingdoms

The Two Kindoms EubacteriaEubacteria ArchaebacteriaArchaebacteria Archaea and eubacteria differ radically from each other

Four main phyla Cyanobacteria, Spirochetes, Gram- positive, Proteobacteria.Cyanobacteria, Spirochetes, Gram- positive, Proteobacteria. Cyanobacteria = photosytheticCyanobacteria = photosythetic Spirochetes = spiral- shaped Spirochetes = spiral- shaped Proteobacteria = gram- negative.Proteobacteria = gram- negative. Kingdom Eubacteria

Origins Most ancient prokaryotes = thermophiles.Most ancient prokaryotes = thermophiles. - life originated in a hot environment!

General Biology of the Prokaryotes Prokaryotes - most numerous organisms on EarthProkaryotes - most numerous organisms on Earth  hot vents/springs  deep in ground  salty, cold, acid or alkaline habitats

The Archaea heat - thermophilesheat - thermophiles salt - halophilessalt - halophiles acid - acidophilesacid - acidophiles Methanogens produce methane by reducing carbon dioxideMethanogens produce methane by reducing carbon dioxide

Thermophiles

Halophiles

General Biology of the Prokaryotes Forms: cocci, bacilli, or spirillicocci, bacilli, or spirilli

General Biology of the Prokaryotes Lack nuclei, membrane- enclosed organelles, and cytoskeletons.Lack nuclei, membrane- enclosed organelles, and cytoskeletons. Chromosomes are circular=plasmidChromosomes are circular=plasmid

4.4

General Biology of the Prokaryotes Movement: Flagella, which rotate (not just wave back and forth).Flagella, which rotate (not just wave back and forth). Gas vesicles, or gliding mechanisms.Gas vesicles, or gliding mechanisms.

General Biology of the Prokaryotes Metabolism: obligate and facultative anaerobesobligate and facultative anaerobes obligate aerobes.obligate aerobes.

Table 26.2

Prokaryotes in Their Environments Bacteria have key role in global nitrogen (and sulfur) cycles. Nitrogen fixationBacteria have key role in global nitrogen (and sulfur) cycles. Nitrogen fixation

Prokaryotes in Their Environments Many prokaryotes live in or on other organisms - effects...Many prokaryotes live in or on other organisms - effects...  neutral  beneficial  harmful 10% of our body weight!

Prokaryotes in Their Environments Minority of bacteria are pathogens.Minority of bacteria are pathogens. - rarely fatal (endotoxins)- rarely fatal (endotoxins)  fever, vomiting...  eg.Salmonella  Borrelia burgdorferi (Lyme Disease)

Prokaryotes in Their Environments sometimes highly toxic (exotoxins)sometimes highly toxic (exotoxins)  do not produce fevers!  eg. tetanus, botulism, cholera, plague, anthrax

Prokaryotes in Their Environments STD’sSTD’s Legionnaires’ diseaseLegionnaires’ disease TBTB dental plaquedental plaque

Characteristics of Cell Wall Contain unique matter called peptidoglycanContain unique matter called peptidoglycan The amount of peptidoglycan can help differentiate bacteria.The amount of peptidoglycan can help differentiate bacteria.  Gram-positive bacteria  Gram-negative bacteria

Examples of Gram negative - Examples of Gram negative - BeneficialBeneficial  Rhizobacteria - helps plants with nitrogen fixation harmfulharmful  Salmonella

Binary FissionBinary Fission  Bacteria divide rapidly  Double numbers approximately every 20 minutes Asexual Reproduction

Sexual Reproduction  Transduction =  virus transfers DNA from one bactera to another

Conjugation Exchange genetic material through pili bridgeExchange genetic material through pili bridge Pictures taken from Microbe World

Transformation Pick up pieces of DNA from dead bacteriaPick up pieces of DNA from dead bacteria

Endosymbiotic Theory one species living within another(the host)one species living within another(the host) smaller photosynthetic & heterotrophic prokaryotes into larger prokaryotic hostssmaller photosynthetic & heterotrophic prokaryotes into larger prokaryotic hosts Formed cell organellesFormed cell organelles chloroplast mitochondria

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