Bacteria General Characteristics – text ref. p 471-490 found in all environments Reproduce very quickly-can double every 20 minutes by Binary Fission

Prokaryotes Archaea –lack peptidoglycan cell walls – no nuclear or organelle membranes - are divided into two domains: Archaea –lack peptidoglycan cell walls Eubacteria- cell wall contains complex carbohydrate peptidoglycans that is outside of the cell membrane

Kingdom Archaebacteria Live in very harsh environments. The extremaphiles – can live in very hot, salty or poisonous environments. Eg: outgassing vents at the oceans floor or the METHANOGENS which release methane gas. Example: Thermoplasma

Kingdom EUBACTERIA Classification –Appendix E pg 1072 EUBACTERIA –(true bacteria) largest group, most are heterotrophs, some are photosynthetic, some produce disease (pathogenic) Examples – Escherichia coli, Streptococcus

Shapes – 3 common shapes 1. bacilli (bacillus) – rod shaped 2. cocci (coccus) – spherical 3. spirilli (spirillum) – spiral 4. some clump together: -streptococci – long chains -diplococci – pairs or small groups -staphylococci – clusters of cells

Structure of Prokaryotic Cells use p 472 to draw and label a prokaryotic cell bacteria cell walls are either Gram + or Gram- depending on how they stain Gram + have 1 cell wall and turn purple Gram(-) have 1 cell wall and a capsule and turn red

Motility (movement) - flagella-some whip or pull with flagella - some spiral or snake forward – spirilli - some glide on a slime layer they secrete - some are sessile (don’t move on their own)

Nutrition 2 main groups depending on how they feed 1. Autotrophs- “self-feeding” – usually photosynthesis is involved – phototrophic autotrophs eg: cyanobacteria chemotrophic autotrophs – oxidize inorganic molecules like N,S, and Fe 2. Heterotrophs – must obtain energy from organic material they ingest. Eg: Salmonella a chemotrophic heterotroph Energy Metabolism- bacteria have 2 ways of gaining energy from their food: a) respiration-uses oxygen to release energy-obligate aerobes b) fermentation-occurs without oxygen-obligate anaerobes like Clostridium botulinum c) faculative anaerobes-don’t require oxygen but can live in it

Lifestyles of Bacteria Bacteria (and all organisms) can be: a) parasitic-live on other organisms (the host) eg: dental placque b) symbiotic-live in a close relationship with another organism in a mutually beneficial way eg: Lichens-a fungus & cyanobacteria combined together c) saprophytic-decomposers-feed on dead organisms- important in food chains to recycle nutrients

Reproduction Usually reproduce asexually by Binary Fission -advantage-double population every 20 min. -disadvantage-offspring identical DNA to parent

Conjugation- a pilli tube connects 2 cells and DNA is exchanged to allow new gene combinations. Not true sexual reproduction because no new cells are made

Reproduction Usually reproduce asexually by Binary Fission -advantage-double population every 20 min. -disadvantage-offspring identical DNA to parent Spore formation - sometimes resistant dormant endospores are made to survive harsh conditions Conjugation- a pilli tube connects 2 cells and DNA is exchanged to allow new gene combinations. Not true sexual reproduction because no new cells are made

The Importance of Bacteria a) Only 2% of bacteria are pathogens! Pathogenic bacteria harm us by releasing toxins and attacking cells/tissues. Diseases include: TB, bubonic plague, typhoid fever, tetanus, syphilis, cholera, diptheria, listeriosis b) Bacteria are essential members of all ecosystems because: 1. Nitrogen fixing-these bacteria are the only organisms on earth capable of taking nitrogen and “fixing” it in a chemical form (NH3 – ammonia). All organisms need nitrogen to make DNA and amino acids to make proteins. Plants like soy house bacteria (Rhizobium) to fix nitrogen for them.

The Importance of Bacteria b) Bacteria are essential members of all ecosystems because: 1. Nitrogen fixing-these bacteria are the only organisms on earth capable of taking nitrogen and “fixing” it in a chemical form (NH3 – ammonia). All organisms need nitrogen to make DNA and amino acids to make proteins. Plants like soy house bacteria (Rhizobium) to fix nitrogen for them. 2. Primary producers- bacteria form the base of most food chains 3.Decomposers- bacteria help to recycle the chemistry of dead material in all food chains 4. Symbiotic relationships- like digesting cellulose for grazers like cows and termites, or finishing digestion off in our large intestine 5.Release oxygen into the atmosphere-anaerobes 6.Sewage and waste treatment plants

Human Uses For Bacteria 1. Foods-cheese, yogurt, alcohol ect. 2. digestion-converting nutrients in our gut 3. drugs-eg: most antibiotics come from bacteria 4. Genetic Recombinant Bacteria-we can splice new genes into bacteria to get them to make things like insulin for us 5. sewage treatment plants 6. environmental clean-up bacteria can detoxify things like oil spills

Controlling Bacteria -these are methods to slow, limit or even stop bacterial growth: 1.sterialization - most bacteria cannot survive boiling water (denatures bacteria proteins) 2.disenfectants - chemicals that kill (lyse) bacteria (alcohol, vinegar, tee tree oil, lemon) (environment which doesn’t support the microbe from growing) 3. food processing – to slow reproductive rates eg: freezing, refrigeration, canning, pickling, salting, dehydrating, sealing in plastic

Hand-in ONE worksheet EACH at end of class for marks Review Activity There are FOUR stations to read material and answer the questions…. You will travel in your group of 4 to visit all of them Follow the yellow or the pink route THERE ARE ONLY FOUR STATIONS Pink station #1 is exactly the same as the yellow station #1 Hand-in ONE worksheet EACH at end of class for marks