Quiz 2

297
-1

Published on

This is a series of lectures on microbiology useful for undergraduate medical and paramedical students

Published in: Health & Medicine, Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
297
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
31
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide
  • Uses of darkfield and Phase contrast microscopy
    View unstained cells
    Not subject to shrinkage, artefacts
    Some bacteria do not stain easily, e.g., spirochetes (Borrelia, Leptospira, Treponema)
    View living cells
    Can observe processes, e.g., motility, predation
  • Quiz 2

    1. 1. Quiz 2 Dr. Ashish Jawarkar M.D. Path Parul Sevashram Hospital
    2. 2. Q-1  Which class of organisms causes the disease in picture
    3. 3. Athlete’s foot
    4. 4.  A. Bacteria  B. Fungi  C. Virus  D. Protozoa
    5. 5. Fungi  Eukaryotic organisms with rigid cell wall  Yeasts   Single-celled Reproduce by budding  Superficial infections    Athlete’s foot Ringworm Thrush  Molds   Large, fuzzy, multicelled organisms Produce spores  Can cause systemic infections
    6. 6. Q-2  Which of the following is semipermeable  A. cell membrane  B. cell wall  C. Nucleus  D. Ribosomes
    7. 7.  Cytoplasmic (Plasma) Thin membrane layer 5-10 nm, separates cell wall from cytoplasm  Acts as a semipermeable membrane: controls the inflow and outflow of metabolites  Composed of lipoproteins with small amounts of carbohydrates
    8. 8. Q-3  What are the contents of Mac Conkey’s medium?  A. Peptone  B. Lactose  C. Neutral Red  D. All of the above
    9. 9. Differential media  A media which has substances incorporated in it enabling it to distinguish between bacteria.  Eg: Mac Conkey’s medium      Peptone Lactose Agar Neutral red Taurocholate  Distinguish between lactose fermenters & non lactose fermenters.
    10. 10.  Lactose fermenters – Pink colonies  Non lactose fermenters – colourless colonies
    11. 11. Q-4  What is this used for?
    12. 12.  For removing oxygen, to grow anaerobic bacteria
    13. 13. ANAEROBIC CULTURE METHODS  Anaerobic bacteria differ in their requirement and sensitivity to oxygen.  Cl.tetani is a strict anaerobe – grows at an oxygen tension < 2 mm Hg. Methods: Production of vacuum  Displacement of oxygen with other gases  Chemical method  Biological method  Reduction of medium 
    14. 14. Production of vacuum:  Incubate the cultures in a vacuum desiccator. Displacement of oxygen with other gases  Displacement of oxygen with hydrogen, nitrogen, helium or CO2.  Eg: Candle jar
    15. 15. Chemical method  Alkaline pyrogallol absorbs oxygen. McIntosh – Fildes’ anaerobic jar  Consists of a metal jar or glass jar with a metal lid which can be clamped air tight.  The lid has 2 tubes – gas inlet and gas outlet  The lid has two terminals – connected to electrical supply.  Under the lid – small grooved porcelain spool, wrapped with a layer of palladinised asbestos.
    16. 16. Working:  Inoculated plates are placed inside the jar and the lid clamped air tight.  The outlet tube is connected to a vacuum pump and the air inside is evacuated.  The outlet tap is then closed and the inlet tube is connected to a hydrogen supply.  After the jar is filled with hydrogen, the electric terminals are connected to a current supply, so that the palladinised asbestos is heated.  Act as a catalyst for the combination of hydrogen with residual oxygen.
    17. 17. Gaspak  Commercially available disposable envelope.  Contains chemicals which generate H2 and CO2 on addition of water.  Cold catalyst – in the envelope  Indicator is used – reduced methylene blue.   Colourless – anaerobically Blue colour – on exposure to oxygen
    18. 18. Q-5  What is resolution  A. the ability of the microscope to enlarge the object  B. the ability of the microscope to show two nearby placed objects separately
    19. 19. Important Vocabulary : magnification  mag-ne-fe-'ka-shen n 1. apparent enlargement of an object 2. the ratio of image size to actual size A magnification of "100x" means that the image is 100 times bigger than the actual object. resolution  rez-e-loo-shen n 1. clarity, sharpness 2. the ability of a microscope to show two very close points separately
    20. 20. Q-6  Which type of microscope has been used for taking this picture?
    21. 21.  A. Bright field microscope  B. Dark field microscope  C. Phase contrast microscope  D. Fluorosence microscope
    22. 22. Bright-field Microscope  Contains two lens systems for magnifying specimens  Specimens illuminated directly from above or below  Advantages: convenient, relatively inexpensive, available  Disadvantages: R.P 0.2 µm at best; can recognize cells but not fine details  Needs contrast. Easiest way to view cells is to fix and stain.
    23. 23. Different magnifications
    24. 24. Special Microscopy Applications  Dark Field  Phase Contrast  Fluorescence  Electron Microscope
    25. 25. Dark Field Microscopy  special condenser diaphragm occludes direct light, passes wide angle light  angle too wide to enter objective diffracted light scattered enters objective objects light on dark background  diffracted light
    26. 26. Phase Contrast Microscopy  light rays through objects of different η → change in phase, not intensity  special ring-shaped condenser diaphragm  special glass disc in objective   change phase differences to intensity differences can view transparent objects as dark on light background (without staining)  Right; human brain glial cells
    27. 27. Fluorescence Microscopy  Illuminate specimen with UV → visible fluorescence (filter removes harmful UV)  View auto-fluorescent objects (e.g., chloroplasts)  Stain with specific fluorescent dyes, which absorb in region 230-350 nm & emit orange, yellow or greenish light  Images appear coloured against a dark background
    28. 28. Electron Microscopy
    29. 29. Q-7  Steps of staining include  1. primary stain  2. decolorisation  3. counter stain Which dyes are used for these steps? In gram staining and acid fast staining
    30. 30. Primary staining Decolorisation Counter staining
    31. 31. Primary stain Decolorisation Counter stain
    32. 32. Q-8  What is sterilisation?  A. Killing all organisms on the object  B. Removing only pathogenic organisms
    33. 33. DEFINITION STERILIZATION The process of freeing an article from microorganisms including their spores.
    34. 34. DISINFECTION: Reducing the number of pathogenic microorganisms to the point where they no longer cause diseases.
    35. 35. Q-9  Which is true?  A. Bacteriostatic agent doesnot kill bacteria  B. Bactericidal agent kills bacteria  C. All of the above
    36. 36. Bacteriostatic Agent: An agent that inhibits the growth of bacteria, but does not necessarily kill them.
    37. 37. Bactericide: An agent that kills bacteria. Most do not kill Endospores. Sporicide: An agent that kills spores.
    38. 38. Q-10  Which method is used to sterilize?
    39. 39.  A. Hot air oven  B. Autoclave  C. Pasteurization  D. Ethylene oxide gas
    40. 40. Q-11  Which organism causes plague  A. streptococcus pneumoniae  B. mycobacterium tuberculosis  C. vibrio cholerae  D. yersinia pestis
    41. 41. Bubonic Plague or the Black Death  Epidemic swept thru Europe in the Middle Ages (13th and 14th centuries)  40 million people were killed  About 1/3 of the population of the continent  Etiological agent:  Yersinia pestis  2 Vectors   Rat Flea Gram (-) rod
    42. 42. Yersinia pestis - Gram (-) bacillus Vectors - Rat and Flea
    43. 43. Bubonic Plague Infection  1. Flea bite with Yersinia pestis  2. Bacteria multiply in the bloodstream  Bacteremia  3. Bacteria localize in lymph nodes, especially axillary and groin areas
    44. 44. 4. Hemorrhaging occurs in lymph nodes, resulting in “black and blue” swellings or Buboes (hence the name Bubonic Plague or Black Death)
    45. 45. Bubonic Plague Infection  5. If untreated, about 50 % Mortality Rate  6. If bacteria spread to the lungs, it becomes Pneumonic Plague and is now highly contagious (Almost a 99 % Mortality Rate)
    1. A particular slide catching your eye?

      Clipping is a handy way to collect important slides you want to go back to later.

    ×