Understanding Bacteria: Classification, Structure, and Adaptations

1. Bacteria Classification of Bacteria A. Domain Archaea – means “ancient bacteria” 1. These are found in extreme habitats a. deep in mud, salty conditions, extreme pH and temp. 2. Prokaryotic cell B. Domain Bacteria 1. Heterotrophs – cannot make their own food a. decomposers (helps recycle nutrients) b. parasitic (3%)

2. 2. Photoautotrophs – make their own food using light a. contain pigments b. algae like bacteria – these are important producers for aquatic ecosystems c. “cyanobacteria” – name of the bacteria that does this 3. Chemoautotrophs – make their own food using chemicals a. use sulfur and nitrogen to make food (this is the rotten egg smelling gas) b. some live on the roots of plants and help the plant get nitrogen through nitrogen fixation…”Rhizobacteria” Mutualism – bacteria has home, plant gets nitrogen

3. II. Structure of Bacteria A. Type of cell – Prokaryotic 1. no nucleus or membrane bound organelles B. DNA is found in the cytoplasm as one circular chromosome C. Contains ribosomes (not membrane bound) D. Drawing of a typical cell: 1. Flagella – moves bacteria 2. Chromosome – one circular piece…area that contains the chromosome is called the “nucleoid” region 3. Pili – attaches bacteria to surfaces and aids in sexual reproduction. It is an extension of the cell membrane 4. Cell Membrane – regulates what goes into and out of cell, also involved in making ATP 5. Cell Wall – protection 6. Capsule – protection (not all bacteria have this)…these types cause more disease in us.

5. C. Shapes of bacterial cells 1. Sphere – “coccus” 2. Rod – “bacillus” 3. Spiral – “spirillum” D. Arrangement of bacterial cells 1. cells are paired – “diplo” 2. Clusters of cells – “staphylo” 3. Chains of cells – “strepto” E. Naming bacterial cells relates to the above. The genus name is a combination of arrangement + shape. Name the following:

6. Diplo-Spirillum Staphylo-Bacillus Staphylococcus

7. III. Adaptations of Bacteria A. Endospores 1. A hard outer covering that enables the cell to live in a dormant state when conditions are not favorable for living. 2. resistant to drying out, boiling, chemicals 3. can survive for thousands of years 4. kill them by pressure cooking or autoclave 5. examples of bacteria that do this are: the bacteria that causes botulism the bacteria that causes tetanus

8. Artist, Charles Bell, paints this picture of a soldier in the last stages of tetanus.

9. Binary Fission IV. Reproduction A. can’t reproduce via mitosis because they have no nucleus B. Binary Fission: asexual reproduction (there is no exchange of genetic information) 1. Chromosome is replicated 2. Copies of chromosome attach to the cell membrane 3. Cell grows and the copies separate 4. Cell divides in two as a partition forms down the middle

10. C. Conjugation: Sexual Reproduction (there is an exchange of genetic information) 1. Transfer of part of the chromosome through the pili to another cell. 2. Why is this type of reproduction important?

11. V. Economic Importance A. Nitrogen fixation – bacteria take Nitrogen from the air and “fixes” it to be a form that plants can use for proteins and DNA. B. Decomposition of biodegradable material (trash, leaves, etc) C. Recycling of nutrients due to decomposition (C, O, N) D. Food 1. yogurt 2. cheese 3. Vinegar 4. butter 5. pickles 6. sauerkraut E. Medicine – antibiotics F. Gene Cloning and product producing (remember pGLO lab)