1 / 35

Bacteria

Bacteria. Biology 11. Prokaryotic Cells. Unicellular No nucleus No membrane-bound organelles Do contain DNA . 2 Kingdoms. Archaebacteria “ancient bacteria” Eubacteria “true bacteria”. Archaebacteria : The Extremists. Live in harsh environments. Methanogens: Produce methane

odele
Download Presentation

Bacteria

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Bacteria Biology 11

  2. Prokaryotic Cells • Unicellular • No nucleus • No membrane-bound organelles • Do contain DNA

  3. 2 Kingdoms • Archaebacteria “ancient bacteria” • Eubacteria “true bacteria”

  4. Archaebacteria: The Extremists • Live in harsh environments

  5. Methanogens: • Produce methane • Live in oxygen free environments • Found in swamps, marshes, stomachs of cows • Sewage disposal plants- help breakdown sewage

  6. Halophiles: Salt-loving • Live in salt pools left after a lake has evaporated • pools have high levels of magnesium and potassium salts • Utah’s Great Salt Lake and Middle East’s Dead Sea

  7. 3. Thermoacidophiles: Heat- and acid-loving • Live around deep ocean vents • Temperatures are often above 100ºC • Anaerobic (without oxygen) • Live in hot, acidic waters of sulfur springs

  8. Eubacteria • Live everywhere except extreme environments • Heterotrophs • Use organic molecules as food source • Some are parasites • Some are saprophytes (feed on dead organisms or organic wastes – break down and recycle nutrients)

  9. 2. Photoautotrophs • Photosynthetic autotrophs - Live in places with sunlight • Cyanobacteria – contain chlorophyll (pigment) that traps the sun’s energy • Live in ponds, streams, and moist areas of land • Composed of chains of independent cells

  10. 3. Chemoautotrophs • Make organic molecules • Obtain energy by breaking down compounds with sulfur and nitrogen and releasing the energy in the process called chemosynthesis • Bacteria in Plants– able to convert atmospheric nitrogen into the nitrogen-containing compounds that plants need

  11. Bacteria Structure • Ribosomes- protein synthesis • Chromosome- single circular DNA molecule • Cell Wall- support and protection • Flagella- motility

  12. Pilli (sing. Pillus) hair like structure to aid in reproduction and attaching to one another • Capsule- sticky, gelatinous, surrounds cell wall to protect against desiccation • Cytoplasm- thick liquid within cytoplasmic membrane • Plasmid- small circular piece of DNA

  13. If Bacteria don’t have mitochondria, how do they get their energy? • Occurs at cell membrane

  14. Identifying Bacteria • Bacteria are separated into two groups based on characteristics of cell wall • Cell walls made of peptidoglycan (sugar and amino acid molecules) which helps structure and maintain shape (target for antibiotics) • Technique called gram staining is used to do this

  15. Gram Stain • First, crystal violet dye is added. Then, a second dye is added. • Gram + bacteria retain crystal violet dye • Gram – bacteria appear red or pink after a counterstain is added (commonly safranin)

  16. Gram-positive: one thick layer of peptidoglycan (protein and sugar) Gram-negative: one thin layer of peptidoglycan and an outer lipid and sugar layer

  17. Identifying Bacteria • Growth pattern • Diplo (paired arrangement) • Staphylo (grape arrangement) • Strepto (chain of cells) • Bacteria shape (plural) • Cocci (spheres) • Bacilli (rods) • Spirilla (spirals)

  18. Strepto-Coccus

  19. Strepto-Bacillus

  20. Spirillum

  21. How do bacteria get around? • Flagella vs Cilia • Flagella use whip like motions to move • Cilia use a beating motion to move (eukaryotes only)

  22. Remember: • Bacterial DNA • Circular • Free floating in the bacterial cytoplasm

  23. A well fed bacteria is two happy bacteria • ATP- when used, turns into ADP (Tri-phosphate or Di-phosphate) • Bacteria have a protein called DnaA that starts the process of DNA replication (first step in fission) • DnaA+ADP = nothing  ; DnaA+ATP = replication

  24. Bacteria Reproduction 1. Asexual by binary fission • DNA replicated • DNA pulled to separate poles as bacterium increases in size • A partition forms and separate the cells • Results in genetically identical cells • Can be rapid –ideal conditions every 20 minutes

  25. Plasmids • Extra circle of DNA that can replicate independently • Can be transferred to another Bacterium • Typically carries a beneficial trait. e.g. antibiotic resistance.

  26. 2. Conjugation • Bacteria conjugate if one of them have special “F” factor (fertility factor) • The F+ bacteria (donor) makes a Pilus, and transfers the F plasmid to the F-recipient. • Recipient is now F+ • Results in a bacteria with new genetic composition

  27. Spore Formation • Endospore: tiny structure that contains a bacterium’s DNA and a small amount of its cytoplasm • Encased by tough outer covering • Resists drying out, extreme temperature, harsh chemicals • If environmental conditions improve, then endospore germinate • To kill endospores, items must be sterilized (i.e. heated under high pressure)

  28. Metabolism • 2 Types: Aerobic and Anaerobic • Aerobic Bacteria require oxygen to produce energy • Anaerobic Bacteria don’t require oxygen to produce energy

  29. When typing Bacteria- Gram’s stain is #1, then comes how they make energy • Obligate Anaerobic (Can’t live with oxygen) • Facultative Anaerobic (can get by either way) • Obligate Aerobic (Can’t live without oxygen)

  30. Where can they get energy from?

More Related