Three Groups of Bacteria

Kingdom Monera
­ bacteria
­ oldest and most abundant living
organisms
­ about 2000 species of which 150 are pathogenic
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Three Groups of Bacteria
1. Cyanobacteria
­ blue green algae
­ photosynthetic (due to blue pigment)
­ need moisture and light
­ most live in freshwater Title: Apr 24­1:44 PM (2 of 13)
Three Groups of Bacteria
2. Archaebacteria "old"
­ first form of life, very primitive
­ live in very harsh environments (tar pits, hot springs, ice caps, mines)
­ chemosynthetic (break down inorganic compounds for energy food
­ produce gases: ex. methane
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Three Groups of Bacteria
3. Eubacteria "true"
­ "true bacteria"
­ can be dormant for long periods of time
­ most have outer covering called a capsule
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Structure of a Prokaryote
cytoplasm
pilli
flagellum
capsule
"nucleoid" cell ribosome
cell wall
region membrane
Most display one of 3 basic shapes: ­ spherical (_________coccus)
­ rod­shaped (_________bacillus)
­ spiral (___________spirillum)
Often group together in clusters, filaments (chains)
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Typical Bacterial Cell (Eubacteria)
­ some heterotrophic, some autotrophic
­ can move by beating a flagellum
­ most reproduce asexually
­ some transfer genetic mateial through a form of sexual reproduction
­ many have a layer of slime that helps them
stick to their food supply
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Typical Bacterial Cell (Eubacteria)
cont'd
­ prokaryotic (no definite nucleus)
­ single celled
­ have enough DNA to make 1 chromosome
­ have cell wall ­ definite shape
­ have cell membrane and cytoplasm (unlike
viruses)
­ no membrane bound organelles
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Classification by Modes of Respiration
Obligate aerobes ­ must have oxygen to survive
Obligate anaerobes ­ only grow in the absence of oxygen
Facultative anaerobes ­ can survive and grow with or without oxygen
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Classification by Modes of Everyone Nutrition
Autotrophs ­ photosynthetic or chemosynthetic bacteria produce their own food
Heterotrophs ­ parasites ­ take their food from
host organisms (most)
­ saprophytes ­ obtain nutrients
from dead/decomposing matter
Done?
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Asexual Reproduction in Bacteria­
Binary Fission
­ "Splitting in two"
­ DNA replicates
­ cell lengthens
­ cross wall forms and divides the cell into 2 identical daughter cells
­ each new daughter cell has 1 chromosome, identical to the parent cell
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replication
chromosome
2 identical daughter cells
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