Chapter 19: Bacteria & Virus Study Guide

1. Chapter 19: Bacteria & Virus Study Guide Edwin P. Davis, M.Ed.

2. Kingdom MoneraSubkingdom Eubacteria

3. Classification of Bacteria • (1) Archaebacteria • The extremists • Oxygen – free environments • Produce methane • Concentrated salt water environments • Great Salt Lake, UT • The Dead Sea, Middle East • Hot, acidic waters of sulfur springs The Dead Sea, Israel The Great Salt Lake, UT

4. (1) Eubacteria • The heterotrophs • Found everywhere • Need organic molecules as an energy source • Parasites • Absorb nutrients from living organisms • Saprobes • Organisms that feed on dead organisms or organic waste • Help recycle the nutrients contained in decomposing organisms Saprobe

5. (2) The photosynthetic autotrophs • Obtain energy from light • Cyanobacteria (cyano, blue-green) • Trap the sun’s energy by photosynthesis using their blue-green pigment • Some are red or yellow • Found in ponds, streams and moist land • Composed of chains of cells

6. (2) The Chemosynthetic autotrophs • Obtain energy from chemosynthetic breakdown of inorganic substances • sulfur or nitrogen compounds • Important in converting nitrogen in the atmosphere to forms readily used by plants Underwater sea vent

7. (3) Five General Characteristics of Bacteria • Microscopic, simple, living • Prokaryotic, no true nucleus • Non-membrane bound organelles • Ribosomes smaller • Inherited information held in single circular chromosome

8. (4) Prokaryotic Cells are identified by: • Their shape • Their chemical nature of their cell walls • The way they move • The way they obtain energy

9. (5) Prokaryotic Cell shape • Bacilli – Rod shape • Cocci – spherical shaped • Spirilla – Spiral & corkscrew

10. (6) Shapes of Bacteria • Shape • Spheres • coccus • Rods • bacillus • Spiral • spirillum

11. (7) Bacterial Cell Arrangement • Diplo – cells are paired • Staphylo – cells are in grape-like clusters • Strepto– cells are in long chains

12. (8) Prokaryotic Cell Walls • Gram Positive Cell Wall – thick peptidoglycan walls • Gram Negative Cell Wall – thinner peptidoglycan walls

13. (9) Important functions of Prokaryotic Cells Bacteria perform many important functions on earth. They serve as decomposers,agents of fermentation, and play an important role in our own digestive system.

14. (10) Examples of Prokaryotic Cells

15. Miracle Cure – The Story of Penicillin (11) Discovered by Alexander Fleming in 1928. (12) Produced from an airborne mold,Penicillium notatum • World’s first antibiotic • Purified in 1940 • Kills bacteria and inhibit their growth Penicillium notatum

16. Penicillin – Bacterial Killer? (13) Interferes with the enzyme that links the sugar chains in the cell wall • Bacteria growing in penicillin develop holes in their cell walls • Water enters, bacteria dies • Not effective in viruses and animals • Neither has cell walls • Nontoxic to plants • Plant cell wall is different structure from bacterial cell wall

17. (14) Prokaryotic Vs. Eukaryotic Cells

18. (15) Adaptations for survival • Endospores • Have hard outer covering • Resist drying out, boiling, freezing, many chemicals • Bacteria is in slow metabolism, does not reproduce • When in favorable conditions, germinates and gives rise to bacterial cell

19. Endospores: Survive in extreme conditions (temp, drought, flood, radiation)

20. (16) Clostridium Botulinum • Obligate anaerobes • Form endospores • Produces an extremely powerful toxin (poison) • Don’t die when exposed to oxygen • Can find their way into canned food • If not properly sterilized • endospores germinate • bacteria grow • produce their deadly toxin • Causes botulism

21. (16) Clostridium Tetani • Produces powerful nerve toxin • Causes often-fatal disease, tetanus • Endospores are found in every surface • Can enter wound easily, germinate and release toxin • Immunization is prevention

22. (17) ANTHRAX • Transmission to humans can occur by direct contact of the skin with the endospores of B. antracis, via the respiratory tract through inhalation of spores, and via the gastrointestinal tract through the ingestion of spores. If disease is inhaled • Mild Fever, Malaise • Fatigue, Coughing • Feeling of pressure on chest If disease contract through skin • a boil develops that eventually forms a black center

23. Anthrax • Anthrax is primarily a disease of animals, however, it can occasionally be transmitted to humans. The disease is caused by Bacillus antracis, a Gram positive, rod shaped, and endospore forming microorganism. • Endospore formation is necessary in times of unfavorable living conditions (e.g. low water availability, extremely high temperatures, etc.). • The bacteria remains dormant until environmental conditions becomes suitable for living

24. Bacteria Reproduction

25. (18) Binary Fission • Asexual reproduction • Copies its single chromosome • Copies attach to cell’s plasma membrane • Cell divides into two as partition forms between two new cells • Each cell has one copy of chromosome Just like mitosis, but the whole organism is copied

26. Binary fission

27. (19) Conjugation • Sexual reproduction • One bacterium transfers all or part of its chromosome to another • Pilus (pili) - Bridge-like structure • Connects two cells • Used to transfer genetic material

28. Conjugation

29. Bacteria Economic Importance

30. (20) Nitrogen fixation • Convert N2 gas into ammonia (NH3) • Convert ammonia (NH3) to nitrite (NO2-) and nitrate (NO3-) • Some form symbiotic relationship with peas, peanuts, and soybeans • Helps them grow better when nitrogen is lacking • When they are harvested, remaining roots add nitrogen to soil Bacteria on legume roots

31. (20) Recycling of nutrients • Cyanobacteria • Replenish supply of oxygen in atmosphere • Autotrophic bacteria • Convert carbon dioxide in the air to the organic compounds that are passed to consumers in food chains and webs • All life depend on bacteria

32. (20) Food and medicines • Used to produce vinegar, yogurt, butter, cheese, pickles, sauerkraut • Used to produce antibiotics to kill other bacteria • Streptomycin • Erythromycin • Chloromycetin • Kanamycin

33. (21) Bacteria cause disease • Half of human disease is caused by bacteria

34. (22) Naming of Viruses • Disease they cause • Rabies virus • Polio virus Rabies virus Polio virus

35. Organ or tissue they infect Adenovirus Attacks adenoid tissue at the back of the throat (22) Naming of Viruses

36. (23) T4 - Bactriophage

37. Polyhedral Looks like small crystal Most have 20 sides Polio virus and T4 – bacteriophage Cylindrical Tobacco mosaic viruses Enveloped viruses Envelope studded with projections HIV and influenza virus (24) Shapes of Viruses

38. Shapes of Viruses Polyhedral T4 - bacteriophage Polio virus

39. Shapes of Viruses Cylindrical Tobacco mosaic virus

40. Shapes of Viruses Enveloped viruses HIV virus

41. (25) The Lytic cycle • DNA injected into cell • Transcription/translation of 100 viral genes • DNase chops up host DNA • DNA modification protects viral DNA • Virus undergoes self-assembly • Lysozyme chews hole in cell wall host cellburst

42. The Lytic Cycle

43. (25) The Lysogenic cycle • Viral nucleic acid is inserted into genetic material of host • Forms provirus • Provirus – virus formed when viral DNA is inserted into the host cell chromosome • Host replicates with it • Can go undetected in this cycle for years • Eventually enter the lytic cycle and kills the host cell

44. The Lysogenic cycle

46. (26) Disease: A condition in which a system, organ or part of an organ doesn’t function properly.

47. (27) Diseases are caused by: • Genetics • Environment • Combination of both • Infections

48. (28) Pathogens are: Disease-causing agents

49. Pathogens • A pathogen is a disease causing agent • Could be bacterial, viral, fungal, or from an animal (usually worms)

50. (29) Defense against infections 1st Line of Defense against Infection • Skin: scab • Stomach: HCl acid • Eyes: Tears (lysozyme enzyme) • Mucous membranes, cilia and nasal hair