Download Unit 10-Bacteria

Bacteria
Dated back about 3.5
billion years ago
Bacterial Characteristics
All prokaryotic
Autotrophic or Heterotrophic
Average size- 1um -500um
Kingdom Archaebacteria
Types of Archaebacteria
Kingdom Archaebacteria
Extreme Halophiles
Methanogens
Thermoacidophiles
Salt-loving
Convert hydrogen gas
& carbon dioxide to methane
High temperature &
high acidity
Kingdom Eubacteria
Phylum Cyanobacteria - (blue-green algae)
photosynthetic
Phylum Spirochetes - Gram negative, spiral
bacteria, heterotrophic, move by a corkscrew
rotation (Ex.) syphilis
Phylum Proteobacteria - Largest group, Enteric
bacteria, chemoautotrophs, nitrogen-fixing
bacteria.
Phylum Gram + bacteria- Have a thick layer of
peptidoglycan.
Bacterial Shapes
Cocci - round
Bacilli - rod
Spirilli - spiral
Prefixes:
Staphylo-form
clusters
Strepto - form chains
Bacterial Structure
DNA (plasmid)
Cell Membrane
Cell Wall
(peptidoglycan)
Glycocalyx attachment (sticky)
Endospore - tough
envelope
Capsule - protection
Pili - attachment
Bacterial Nutrition
Heterotrophic - feed on dead, decaying
organic matter, called saprophytes.
Photoautotrophs - use sunlight as a
source of energy.
Chemoautotrophs - use chemical
reactions as a source of energy.
Bacterial Respiration
Obligate Anaerobes - cannot live in the
presence of oxygen.
Facultative Anaerobes - can live with or
without oxygen.
Obligate Aerobes - cannot live in the
absence of oxygen.
Bacterial Reproduction
Rapid reproduction
Heat, cold, predators,
& lack of food inhibit
reproduction.
Methods:
Binary fission asexual
Conjugation - sexual
Production of Toxins
Pathogen - any organism that causes a
disease.
Toxin - Poisonous substances that disrupt
the metabolism of the infected organism.
Endotoxin - found in the cell wall
Exotoxin - secreted into areas around
bacteria.
Antibiotics
Inhibit growth of
some bacteria.
Disadvantages:
Destroy useful
bacteria as well.
Resistance of bacteria.