BACTERIA
BACTERIA Kingdom Eubacteria (true) Domain Archea, Domain Bacteria, Domain Archea, Used to be combined under Kingdom Monera * Prokaryotic cell type * Heterotrophic or Autotrophic Kingdom Eubacteria (true) Kingdom Archaebacteria (ancient)
Kingdom Archaebacteria Kingdom Eubacteria Kingdom Archaebacteria PROKARYOTES Archaea are more closely related to the eukaryotes, while the bacteria are related to cell organelles such as mitochondria and chloroplasts.
Recall Prokaryotic Vs. Eukaryotic Prokaryotes DO NOT have: Nucleus Membrane-bound organelles Prokaryotes DO have: DNA (all) Ribosomes (all) Cell membrane (all) Cytoplasm/Cytoskeleton (all) Cell Wall (many) Flagella (some) Capsule (many) Pili (some) Ex. bacteria Eukaryotes DO have: Nucleus Membrane-bound organelles (such as mitochondria, ER, golgi, etc.) DNA (inside nucleus) Ribosomes Cell membrane Cytoplasm/Cytoskeleton Cell Wall (some) Flagella (a few) Ex. Animals, Plants, Fungi, Protists
Eubacteria Diagram Plasmid is a small circular DNA molecule Good web-site to look at eubacteria cell structure: http://www.enchantedlearning.com/subjects/bacterium/
Pili on a bacillus bacterium Pili are used by a bacterium to attach to surfaces and also to exchange genetic material
CHARACTERISTICS of Bacteria: 1. Reproduce asexually through binary fission. ( Dividing in half; identical offspring) Classified by cell shape, cell wall, respiration (aerobic/anaerobic) and nutrition. Can be Gram + or Gram -
Characteristics of Bacteria Some may form endospores when growth conditions become very unfavorable (heat, dryness). Endospores have a thick internal wall that encloses DNA and a portion of the cytoplasm. Endospores can remain dormant for months or even years in harsh conditions
When conditions turn favorable, the bacteria will grow from the spore Example: Anthrax; Clostridium botulinum (causes Botulism—a form of food poisoning)
Characteristics of Bacteria continued Toxins – chemicals produced by bacteria that are poisonous to eukaryotic cells and cause disease 6. Conjugation – exchange of genetic material (usually in the form of a plastid) through the pili between 2 bacteria. This leads to genetic diversity
Conjugation in Bacteria
Asexual reproduction Rod-shaped bacteria dividing by binary fission
3 Different Bacterial Shapes bacillus coccus spirillum
3. Three different shapes: 1. Coccus (spheres): 2. Bacillus (rods): 3. Spirillum (spirals): Two different arrangements: Strepto (chains) Staphylo (clusters) What would diplo be?
Archaebacteria: “ancient” Autotrophic Cell walls with NO peptidoglycan found in harsh environments 1. Methanogens- no oxygen, make methane gas 2. Thermophiles- very hot water 3. Halophiles- very salty conditions, 10x saltier than ocean water
Archaea in San Francisco Bay area – extremely high salinity. What kind of archaea are these? halophiles
EUBACTERIA “true” Largest and most diverse of the bacterial kingdoms Found everywhere Most are heterotrophic Cell walls are present with peptidoglycan Many have flagella that aid in movement
Nutrition Types Principal decomposers (along with fungi) AUTOTROPHS Photosynthetic—use pigments to capture light energy to convert to chemical energy ex. cyanobacteria Chemosynthetic—use inorganic molecules or organic molecules to make amino acidsproteins; live in soil and nitrify ammonia ex. sulfur bacteria & methanogens; nitrifying bacteria (Nitrobacter spp.) HETEROTROPHS Principal decomposers (along with fungi) Many produce antibiotics (ex. Streptomyces) Some fix nitrogen (ex. Rhizobium)
Comparison Gram + & Gram - Eubacteria Feature Gram + Gram - Color Purple Red Amount of peptidoglycan More Less Toxicity Antibiotic effective against? Most of the time Not always
Peptidoglycan – the light tan rods in the diagram; lots in Gram +, little in Gram - (the lipid layer on the outside makes it hard for antibiotics to work on G-)
Diseases caused by Bacteria: * Tuberculosis * Anthrax * Lyme disease * E. coli * Bubonic plague *Typhoid fever *Cholera *Strep throat *Dental cavities *diphtheria *pneumonia *Salmonella
Yellow bacillus bacteria in the lining of the human nose Yellow bacillus bacteria in the lining of the human nose. This species causes pneumonia.
How do Bacteria Cause Disease? Destroy living cells and tissues of the infected organism . Example: bacteria causing tuberculosis Release toxins (poisons) that interfere with the normal activity of the host cell which upsets homeostasis. Example: botulism
Controlling Bacterial Infections Antibiotics – block the growth and reproduction of bacteria Vaccines – prevent bacterial diseases by stimulating the body’s immune system. A vaccine can be a made from weaken or killed pathogens or inactivated toxins Good sanitation and food storage
Beneficial Bacteria: There are some bacteria you’ve just got to love! * Decomposers * Nitrogen fixers (fix nitrogen gas in the atmopshere to a useful form) * Bacteria is used to make certain foods like cheese and yogurt. * To manufacture plastics and many pharmaceuticals. * Digests cellulose in animals * Remove human-made waste products sewage treatment plants * Remove poisons from water * Make medicines and insulin through genetic engineering
Develop Mutualistic relationships with other organisms: Ex Develop Mutualistic relationships with other organisms: Ex. the fish provides the bioluminescent bacteria under its eye with organic materials, the fish uses its living flashlight to lure prey and to signal potential mates.