BACTERIA Structure, Function, Reproduction, and Growth

CLASSIFYING PROKARYOTES  There are two groups or kingdoms:  Eubacteria  Live almost everywhere  Archaebacteria  Live in harsh environments  May be the ancestors of eukaryotes

COMPARE THE KINGDOMS are classified into the kingdoms of live in harsh environments such as include a variety of lifestyles such as EubacteriaArchaebacteria Infecting large organisms Thick mudLiving in soil Animal digestive tracts Salty lakesHot springs Bacteria

WHAT ARE BACTERIA?  Single-celled organisms  Prokaryotes  No distinct nucleus  No membrane-bound organelles  Size = 1-5 micrometers  Very small, very primitive cells  About 10 times smaller than eukaryotic cells  HOWEVER, they are much larger than viruses

IDENTIFYING PROKARYOTES  Prokaryotes are identified by:  Their shape  The ways they move  The ways they obtain energy

BACTERIA SHAPES  Bacteria come in three basic shapes  Coccus  Round, spheres  Bacillus  Rods  Spirillum  Spiral or spring-like

MOVEMENT  Some are propelled by a flagellum  Some glide slowly along a layer of slime-like material they secrete  Some do not move at all

OBTAINING ENERGY  Autotrophs  Photoautotrophs  Carry out photosynthesis (cyanobacteria)  Chemoautotrophs  Obtain energy from inorganic molecules (ie. Ammonia, hydrogen sulfide, nitrites, sulfur, or iron  Heterotrophs  Take in organic molecules and then break them down  Photoheterotrophs  Combination between autotrophs and heterotrophs; they photosynthesize and need organic compounds for nutrition

BACTERIA GROW IN GROUPS  Diplo  Pairs  Strepto  Chains  Staphlo  Clusters diplococcus diplobacillus streptobacillus streptococcus staphlobacillusstaphlococcus

REPRODUCTION  Binary fission  Asexual  Cell grows nearly double in size, replicates its DNA, and divides in half  Produces 2 identical “daughter” cells  View binary fission View binary fission

WHAT BACTERIA NEED FOR GROWTH  Moisture  Food  Warm temperature  Most need oxygen (aerobic bacteria), however, some die in the presence of oxygen (anaerobic bacteria)  Where are these growth requirements met?  Incubators  Inside bodies of birds and mammals

WHAT STOPS BACTERIA GROWTH?  Cold temperature  Dryness (freeze-dried foods)  No food  No oxygen (for aerobes)

BACTERIA Beneficial and Harmful Aspects

BENEFICIAL ASPECTS  Help digest food in intestine  Help in food processing  Break down waste in sewage  Ferment sugars to make alcohol  Can be used to make medicine  Decompose dead organisms to return nutrients to soil or water  Some help fertilize soil by forming nitrates and nitrites  Nitrogen-fixing bacteria living on plant roots  Convert nitrogen into ammonia (form that plants can use)  Can be used to clean up oil spills  Petroleum eating bacteria

HARMFUL ASPECTS  Spoils food  At home  In stores  In transit  In restaurants  In the field  Contaminate water  Cholera & typhoid  Contaminate food  Salmonella & botulism  Food needs to be pasteurized (heated up to a really high temperature)  Damage leather  Soil bacteria  Cause disease  Only 1 percent of bacteria cause disease

COMMON DISEASES CAUSED BY BACTERIA Tooth decay Lyme disease Tetanus Tuberculosis Salmonella food poisoning Pneumonia Cholera Streptococcus mutans Borrelia burgdorferi Clostridium tetani Mycobacterium tuberculosis Salmonella enteritidis Streptococcus pneumoniae Vibrio cholerae Regular dental hygiene Protection from tick bites Current tetanus vaccination Vaccination Proper food-handling practices Maintaining good health Clean water supplies DiseasePathogenPrevention