Bacteria

1. Bacteria Biology A Bacterium Borrelia burgdorferi is responsible for Lyme’s Disease.

2. Bacteria Very small cells, no nucleus or other organelles. Prokaryotes!!!

3. Bacteria facts • Most numerous organism on earth • Found everywhere • From the deepest oceans to the air above the highest mountains. • Bacteria divided into two domains • Domain Bacteria includes eubacteria • Domain Archae includes archaebacteria

4. Eubacteria • Most studied organism • Found everywhere except extreme environments • Have strong cell walls containing peptidoglycan. • Some have a second cell wall • Some bacteria are photosynthetic Halomonadaceae Planctomyces

5. Archaebacteria—the Extremists • Thermoacidophiles • Hot acidic environments like the sulfur springs, • thermal vents of ocean floor, or around volcanoes • Many are anaerobes (no oxygen) • Halophiles • Salty environments like the Great Salt Lake and Dead Sea • Usually aerobic • Methanogens • Obligate anaerobes (no O2) use CO2 and give off methane • Found in sewage plants, swamps, near volcanic vents. Thrive in digestive tract of humans and other animals (They are responsible for gases released from lower digestive tract.) Methanosarcina mazei. These primitive archaebacteria have unusual membranes and are methane producers.

6. Archaebacteria…Eubacteria… • What’s the difference? • Peptidoglycan in cell wall • Present for eubacteria • Not present for archaebacteria • Different lipids in plasma membranes • Different ribosomal proteins and RNA • Ribosomes of archaebacteria similar to eukaryotes

7. Prokaryote Structure

8. Prokaryote Identification • By Shape • By Cell Wall Composition • By Movement

9. Bacteria can be one of three shapes. Spheres—cocci Rods—bacilli Spirals—spirochetes Bacteria Shapes

10. Bacteria Shapes • Bacteria can grow in characteristic patterns. • Diplo- paired arrangement of cell growth • Staphylo-arrangement of cell that resemble grapes • Strepto-arrangement of cells that resemble chains

11. Cell Wall: Gram Staining • Staining technique that distinguishes two groups of bacteria because the stain reflects a basic difference in the composition of bacterial cell walls. • The cell walls of all bacteria are made of interlinked sugar and amino acid molecules that differ in arrangement and therefore react differently to Gram Stain.

12. Gram Staining • Gram Positive Bacteria are purple after staining. • Gram Negative Bacteria are pink after staining. • Gram Positive bacteria are affected by different antibiotics than Gram Negative bacteria.

13. Movement • Some remain stationary • Some have flagella • Some move by gliding over their own slime!

14. Reproduction of Prokaryotes • Binary fission • Asexual process in which chromosome replicates, then the two separate, cell elongates then separates into two • Can occur every 20 minutes in ideal conditions • Conjugation • Two prokaryotes attach and • exchange genetic information • New gene combinations are created and diversity is increased.

15. Metabolism of Prokaryotes • Heterotrophic bacteria live all around us and use organic molecules as a food source. • Some are parasites, obtaining their nutrients from living organisms. • Others are saprotrophs which obtain their nutrients from dead organisms or organic wastes.

16. Metabolism of Bacteria Autotrophic means that it makes it’s own food. • Photoautotrophs are photosynthetic autotrophs living in places with sunlight because they need it to make their own food. • Cyanobacteria are photosynthetic autotrophs that contain the green pigment chlorophyll that traps the sun’s energy, which they then use in photosynthesis.(Once called blue-green algae because they were thought to be eukaryotes) • They are found in ponds, streams, moist areas of land.

17. Metabolism continued • Chemoautotrophs are autotrophic too, because they make their own food. • Do not require light for energy • They break down and release the energy of inorganic compounds containing sulfur and nitrogen in the process called chemosynthesis. • They are important because they can convert atmospheric nitrogen into the nitrogen-containing compounds that plants need.

18. More Metabolism Aerobes and Anaerobes • Obligate aerobes require oxygen to grow • Obligate anaerobes do not use oxygen for growth or metabolism • Obtain energy from fermentation • Facultative anaerobes can grow with oxygen or anaerobically using fermentation

19. Bacteria Survival • Endospores: bacterial cell becomes dormant in harsh environments by surrounding chromosomes and small amount of cytoplasm with a spore coat. When conditions become favorable the endospore grows or germinates into a new bacterial cell. • anthrax, botulism, and tetanus are endospore producers

20. Bacterial Survival • Mutations—changes or random errors in DNA lead to new forms of genes or new gene combinations, new characteristics, and genetic diversity. • Survival of the fittest!

21. Ecology of Bacteria The Good Ones • Decomposers/recyclers • Normal flora-live on us (E. coli) • Make up food (yogurt, cheese, wine, beer, even chocolate!) • Used in Genetic Engineering • Fix Nitrogen for Plants • Medicines- some bacteria make anitbiotics that affect other bacteria cells.

22. Ecology of Bacteria The Bad Ones can cause: • STD’s, Strep throat, pneumonia, whooping cough, TB, anthrax, acne, infected wounds, food poisoning, botulism, tetanus, bacterial meningitis, lyme’s disease, typhoid