Download Bacteria

Bacteria
Bacteria differ from Eukaryotes
 No nucleus or membrane bound organelles
 10 times smaller
 Unicellular, activities not specialized
 Single chromosome
 Reproduce by binary fission
 Simple flagella that spins, pili for adherence
 Many metabolic abilities, perform any aerobic
and anaerobic processes
Structure of bacteria
 3 basic shapes
1.
2.
3.
Bacillus – rod shaped cell
Coccus – round shaped cell
Spirillum – spiral cell
Structure of bacteria
 Cell membrane and cell wall
 Capsule – gel like layer outside cell wall
 Endospores – in harsh conditions, form
around chromosomes and cytoplasm.
 Pili – adhere to surfaces
 Conjugation – exchange of genetic material
Bacteria obtain energy many ways
 Photosynthetic bacteria – many bacteria carry out
photosynthesis
ex. Cyanonbacteria
 Chemoautotrophic bacteria – obtain energy by
removing electrons from inorganic (NH3) or organic
molecules (methane). Play important role in nitrogen
cycle.
 Heterotrophic bacteria – feed on organic material
formed by other organisms, decomposers
Gram staining (Lab)
 Gram + - bacteria with a thick layer of
peptidoglycan, stain violet
 Gram - = bacteria with a thin layer of
peptidoglycan, stain pink
 Important because they differ in susceptibility
to antibiotics
 Knowing whether a bacteria is gram + or
gram – will help a doctor choose the most
effective antibiotic.
Bacteria cause disease
 Metabolize host – secrete enzymes to break
down organic structures
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TB – bacteria grow on human tissue in lungs
Acne – metabolize oil produced in glands,
plugs the pores, forming pimples
Bacteria cause disease
 Toxins – bacteria secrete chemicals (toxins)
that are poisonous to eukaryotic cells
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Food poison – bacteria grow and produce
toxins in food. This causes illness in humans
that eat the contaminated food
Botulism – poorly canned food – not heated
enough to kill endospore
E. coli poisoning – raw/inappropriately
cooked ground beef
Fighting Bacteria
 Hot soapy water
 antibacterial products
 Antibiotics- natural or synthetic
Importance of bacteria
 Foods are processed by bacteria
 Pickles, buttermilk, cheese, sauerkraut, olives, vinegar
 Industrial uses
 Acetone, butanol (bases for other useful chemicals)
 Genetic engineering
 Mining – concentrate desired elements from low
grade ore
 Environmental - help clean up environmental
disasters by metabolizing organic chemicals, oil and
chemical spills