Monera Part 2

Gram Stain Procedures 1. 3a. 3b. 2. DYE- Crystal Violet

Counterstain to see the Gram Stain Procedures 4. 5. Counterstain to see the gram - bacteria After the alcohol wash, Gram + = purple Gram - = colourless

Examples Yoghurt Bacteria (Lactobacillus and Streptococcus)

E.coli

A mixture

Based on your knowledge Can you tell which type of bacteria is more resistant to drugs? - +

More Gross Infections For You

Other ways to Classify Bacteria Presence or Absence of a Slime Capsule: Protects against dryness Increases virulence Movement

Other ways to Classify Bacteria Energy & Nutrition Requirements: Autotrophs (make their own food) Phototrophic Autotrophs Obtain energy from SUNLIGHT ex. Cyanobacteria Chemotrophic Autotrophs - Obtain energy from INORGANIC molecules like H2S and NO2 ex. Rhizobium – nitrogen fixation (p.372) (make N useable for plant) photosynthesis

Other ways to Classify Bacteria Heterotrophs (more efficient) Chemotrophic Heterotrophs - Obtain carbon from ORGANIC compounds ex. Salmonella ii. Phototrophic Heterotrophs - Obtain energy from sunlight but need ORGANIC molecules for nutrition

Feed on organic molecules

Other ways to Classify Bacteria Oxygen Requirements: Obligate aerobe – require O2 (breathing) Obligate anaerobe – must live in absence of O2 (O2 kills them - fermentation) Facultative anaerobe – can live with or without O2

Other ways to Classify Bacteria D) Bacterial Reproduction: Binary Fission asexual form of reproduction in bacteria DNA replicates and cell pinches into two

Conjugation Form of sexual reproduction in some bacteria Protein bridge called a pilus forms between 2 bacteria and genetic information is transferred from 1 cell (the donor) to the other cell (the recipient) Advantage  new genetic combination  more resistant

Endospores (inside, pockets) Formation of hard resistant spores when conditions are hostile (too dry, too hot) An internal wall forms around the DNA and part of the cytoplasm Can last for months When favourable conditions return binary fission resumes Technically not reproduction but allows bacteria to survive through harsh conditions

Conditions Required for Growth Temperature (usually warm) Moisture Light Ample food (more than enough) Right pH (acidity) level Oxygen or Oxygen free

Growth Curve of Bacteria p. 379 Wastes buildup Food is depleted Bacteria die Lots of food good condition rapid growth Bacteria compete for food # stabilize (Death = Birth) Limit to carrying capacity of environment Slow growth: bacteria adjusts to environment

Bacteria and Us Food products - cheese - fermented dairy products - yoghurt, buttermilk - pickles, sauerkraut - vinegar and wine Others - antibiotics (Erythromycin) - digest petroleum (cleaning up oil spills) - dyes (able to make indigo for jeans) - vitamins (K – in the human body)

Ecological Roles of Bacteria Symbionts Symbiosis: a close relationship with another organism in which the bacteria and organism both benefit Ex. E.coli Decomposers Recycle (break down) dead material Saprophyte: organisms that use complex molecules of once-living (dead) organism as their source of energy and nutrition

When a Tree Dies Tree dies and falls Insects and bacteria Wood softens and bark peels off Tree crumbles into soil

Ecological Roles of Bacteria Sewage Treatment Decompose material in waste water Waste water: human waste, discarded food, organic garbage, and chemical waste Produce purified water Nitrogen gas CO2

Ecological Roles of Bacteria Nitrogen Fixation All organisms are dependent on bacteria for nitrogen Plants use nitrogen to produce AAs But atmospheric nitrogen is not usable to plants Bacteria fix N2 to NH3