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. Bacillus – rod shaped cell

2. Coccus – round shaped cell

3. 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 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 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