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Bacteria
Objective: G3 - Describe bacterial structure, &
summarize the role of bacteria in both
maintaining & disrupting the health of both
organisms & ecosystems
Bacteria
singular: bacterium / plural: bacteria
▪ Microscopic Prokaryotes
▸LACK CELL NUCLEUS
▪ Until recently, bacteria were placed into one Kingdom
-Kingdom Monera, hence sometimes bacteria are
referred to as Monerans
▪ Most numerous organisms on earth
Before the doctors told us of the danger of a kiss
I considered kissing you nothing short of bliss
But now I know the danger and I sit and sigh and moan -Six billion small bacteria, and I thought we were alone.
Kingdom Monera
Is now two kingdoms:
▪ Kingdom Eubacteria (true bacteria)
– Tend to be smaller
– Classified according to their mode of getting
nutrients, mechanism of movement, and their
shape
▪ Kingdom Archaebacteria (ancient bacteria)
– Tend to be larger
– Tend to live in extreme environments
Diversity
Metabolic
▪ Some are heterotrophs (get
energy by consuming organic
molecules made by other
organisms) and some are
autotrophs (make their own
food)
Diversity
of Bacteria Naming
▪ Cocci - sphere
▪ Bacilli - rods
▪ Spirilla - spirals
Staph - in clusters
Strep - in chains
Reproduction
▪ Binary fission - one cell splits into
two cells, offspring are genetically
identical to parent 
▪ Conjugation - a form of sexual
reproduction where bacteria
exchange genetic information
before dividing, offspring have new
genes (and new traits)
Beneficial Bacteria
Harmless and beneficial bacteria far outnumber harmful varieties.
▪ Main decomposers of dead organisms to
recycle nutrients
▪ Breakdown chemical & oil spills
▪ Soil enrichment
▪ Preservation by pickling
▪ Fermentation
▪ Live in intestines and help organisms digest
food (exp. E. coli )
Harmful Bacteria
▪ Some bacteria are known as pathogens
▪ Cause disease
▪ Can produce poisonous toxins
Bacteria Motility (ability to move)
▪ Flagella – whiplike tail
▪ Pili – tiny hairlike projections
▪ Gliding over slime they secrete
Antibiotics (means against life)
▪ Used to fight harmful bacteria, but
sometimes it hurts the beneficial
bacteria too
▪ Does not work on VIRUSES
because they are NOT LIVING
▪ Inhibit the growth of or destroy
bacteria