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Eukaryotes v. Prokaryotes

Eukaryotes v. Prokaryotes. Prokaryotes Characteristics. Single cell No true nucleus few organelles Archaebacteria – extreme environments Eubacteria. Eukaryotes v. Prokaryotes. Eukaryotes. Prokaryotes. Smaller Not as complex No nucleus Have single strand of DNA and plasmid

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Eukaryotes v. Prokaryotes

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  1. Eukaryotes v. Prokaryotes

  2. Prokaryotes Characteristics • Single cell • No true nucleus • few organelles • Archaebacteria – extreme environments • Eubacteria

  3. Eukaryotes v. Prokaryotes Eukaryotes Prokaryotes Smaller Not as complex No nucleus Have single strand of DNA and plasmid No membrane bound organelles 70S Ribosome Bacteria • Larger (up to 100 times!) • More complex • Nucleus • Have chromosomes • Membrane bound organelles • 80S Ribosome • Animals, plants, protists

  4. Bacteria and Viruses Chapter 18 18.1 Bacteria Diversity of Prokaryotes • Bacteria are microscopic organisms that are prokaryotes. • Prokaryotes are divided into two domains— 1. Domain Bacteria (eubacteria) and 2. Domain Archaea (archaebacteria).

  5. Bacteria and Viruses Chapter 18 18.1 Bacteria Photosynthetic eubacteria Archaebacteria Eubacteria 3000x 9560x magnification unavailable

  6. Bacteria and Viruses Chapter 18 18.1 Bacteria Eubacteria • Very strong cell walls • Determines shape • Contain peptidoglycan • Some have a second cell wall

  7. Bacteria and Viruses Chapter 18 18.1 Bacteria Archaebacteria- aka Extremophiles • Thermoacidophiles (thur muh uh SIH duh filz) live in hot, acidic environments. • Halophiles (HA luh filz) live in very salty environments. • Methanogens (meh THAHN oh jenz) cannot live in the presence of oxygen.

  8. Archaebacteria • Cell walls made from different materials than eubacteria • Cell membrane lipids different from eubacteria • DNA sequences are more like eukaryotes than eubacteria

  9. Bacteria and Viruses Chapter 18 18.1 Bacteria Differences Between Eubacteria and Archaebacteria • The cell walls of the eubacteria contain peptidoglycan, but the cell walls of archaebacteria do not. • The two groups of organisms have different lipids in their plasma membranes. • Different ribosomal proteins and RNA

  10. Bacteria and Viruses Chapter 18 18.1 Bacteria Prokaryote Structure • Prokaryotes are microscopic, unicellular organisms. • They have some DNA and ribosomes. • Lack membrane bound organelles

  11. Bacteria and Viruses Chapter 18 18.1 Bacteria • Chromosome (no nucleus) • May contain extra DNA in circular plasmid

  12. Bacteria and Viruses Chapter 18 18.1 Bacteria • Capsule- protection, attachment & prevents dehydration • Pili- hair-like projections allowing for attachment & reproduction • Size- very small!

  13. Bacteria and Viruses Chapter 18 18.1 Bacteria Identifying Prokaryotes • Shape • Spherical = Cocci • Rod-shaped = Bacilli • Spiral-shaped = Spirochetes Spirochetes Bacilli Cocci 5460x 2000x 400x

  14. Named by Arrangement: • strep = long chains • staph = clumps, • diplo = pairs • Spirillum/spirochete= corkscrew • Comma-shaped= vibrio

  15. Bacteria and Viruses Chapter 18 18.1 Bacteria Cell Walls • Eubacterial cells have peptidoglycan. • Dyes added to the bacteria identify those with and those without an outer layer of lipid. Purple = gram positivecell wall contains peptidoglycan

  16. Bacteria and Viruses Chapter 18 18.1 Bacteria Movement • Prokaryotic flagella are made of filaments. • Flagella help prokaryotes to move toward materials that they need to survive.

  17. Releasing energy • Obligate aerobes – carry out cellular respiration with oxygen • Obligate anaerobes – cannot live in presence of oxygen • Clostridium botulinum - botulism • Facultative anaerobes – can live with or without oxygen

  18. Bacteria and Viruses Chapter 18 18.1 Bacteria Reproduction of Prokaryotes • Binary Fission • Division of a cell into two genetically identical cells • Asexual • Conjugation • Two prokaryotes attach to each other and exchange genetic information. • Sexual

  19. Bacteria and Viruses Chapter 18 18.1 Bacteria Survival of Bacteria • Endospores • Resistant and able to survive harsh environments • Survival advantage!

  20. Bacteria and Viruses Chapter 18 18.1 Bacteria Mutations • Bacteria populations grows rapidly. • Mutations lead to new forms of genes, new gene combinations, new characteristics, and genetic diversity. • Survival advantage!

  21. Bacteria and Viruses Chapter 18 18.1 Bacteria Modes of Obtaining Nutrients: Photoautotrophs • Carry out photosynthesis Chemoautotrophs • Break down and release compounds that contain nitrogen or sulfur Aerobes and Anaerobes • Obligate aerobes are bacteria that require oxygen to grow. • Anaerobic bacteria do not use oxygen for growth or metabolism.

  22. Bacteria and Viruses Chapter 18 18.1 Bacteria Normal Flora • Most of the bacteria that live in or on you are harmless and are called normal flora. 21,674x E. coli

  23. Bacteria and Viruses Chapter 18 18.1 Bacteria Ecology of Bacteria • Nutrient cycling and nitrogen fixation • Bacteria are decomposers, returning vital nutrients to the environment. • Nitrogen-fixing bacteria live in a symbiotic relationship in the root nodules of plants such as soybeans, clover, and alfalfa.

  24. Bacteria and Viruses Chapter 18 18.1 Bacteria Disease-causing Bacteria • A small percentage of bacteria cause disease. • Bacteria multiply quickly at the site of infection. • Bacteria secrete a toxin or break down tissue.

  25. Bacteria and disease • Pathogens – disease causing agents (small percentage of bacteria) • Treated with antibiotics – block the growth and reproduction of bacteria Lung infection

  26. Controlling bacteria • Sterilization – destroy bacteria by subjecting them to great heat or chemical action • Disinfectants – chemical solution that kills bacteria • Refrigeration – bacteria grows more slowly in cold temps. – food • Boiling at high temps to kill bacteria • Salt, vinegar, sugar

  27. Bacteria’s Importance • Photosynthetic producers release oxygen • Decomposers: allow recycling of nutrients • Oil spill clean up, sewage treatment • Nitrogen fixation produce nitrogen

  28. Bacteria and Viruses Chapter 18 18.1 Bacteria Foods and Medicines • Some foods & medicine are made with the aid of bacteria. • cheese • yogurt • buttermilk • pickles • vitamins • antibiotics

  29. Nitrogen fixers • Plants depend on nitrogen to make amino acids and proteins →animals get nitrogen from plant proteins • Nitrogen from atmosphere must be converted to ammonia NH3 before plants can use it • This is done by “nitrogen-fixing” bacteria • Symbiotic relationship between plants and bacteria - Rhizobium

  30. Bacteria and Viruses Chapter 18 18.2 Viruses and Prions Viruses • A nonliving strand of genetic material within a protein coat • No organelles to take in nutrients or use energy • Cannot make proteins • Cannot replicate on their own

  31. Structure • Contain a nucleic acid and protein • HEAD region • Capsid--protein coat with nucleic acid core • TAIL region • to attach to host

  32. Bacteria and Viruses Chapter 18 18.2 Viruses and Prions Viral Infection • In order to replicate, a virus must enter a host cell. • The virus attaches to the host cell using specific receptor site on the plasma membrane. • Many viruses cannot be transmitted between different species.

  33. RNA DNA Head RNA Capsid Capsid proteins Tail sheath Tail fiber Surface proteins Membrane envelope Figure 19-9 Virus Structures Section 19-2 Tobacco Mosaic Virus T4 Bacteriophage Influenza Virus

  34. Bacteria and Viruses Chapter 18 18.2 Viruses and Prions Lytic Cycle • The host cell makes many copies of the viral RNA or DNA. • Lysis of host cell Lysogenic Cycle • Viral DNA inserts, or integrates into a chromosome in a host cell. • Infected cell will have the viral genes permanently.

  35. Bacteria and Viruses Chapter 18 18.2 Viruses and Prions Retroviruses • Viruses that have RNA instead of DNA for their genetic material • Contains the enzyme reverse transcriptase • Retroviruses have a protein capsid.

  36. Bacteria and Viruses Chapter 18 18.2 Viruses and Prions Bacteriaphage • A virus that infects bacteria Other Viruses • HIV/AIDS- spread through sexual contact • Rabies- effects nervous system • HPV- cancer causing virus

  37. Figure 19-10 Lytic and Lysogenic Infections

  38. Bacteria and Viruses Chapter 18 18.2 Viruses and Prions

  39. Figure 19-11 Viruses and Cells Section 19-2

  40. Pathogenic viruses • Ebola zaire-- • AIDS • rhinoviruses • influenza • measles, mumps, chicken pox • polio • rabies • smallpox

  41. Vaccines • “cow pox”--Edward Jenner • 1796 • Human Papilloma Virus (HPV)- GARDASIL by Merck • 2008

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