Term
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Definition
| - The process of destroying all liing organisms and viruses |
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Term
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Definition
| - The elimination of harmful microorganisms, but not necessarily endospores, from inanimate objects and surfaces |
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Term
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Definition
| - Inhibit the growth of microorganisms |
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Term
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Definition
| - Kills microorganisms and viruses |
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Term
| 2) State whether moist or dry heat is more effective in controlling microorganisms and indicate why |
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Definition
| - Moist heat is generally more effective than dry heat for killing microorganisms because of its ability to penetrate microbial cells |
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Term
| 3) State two methods of applying moist heat |
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Definition
| - Autoclaving and boiling water |
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Term
| 4) Briefly describe the process of autoclaving (pressure, time and temperature) |
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Definition
| - Autoclaving employs steam under pressure. Materials are placed under 15 pounds of pressure which raises the boiling point of water from 100C to 121C which is sufficient to kill bacterial endospores. Usually in about 15-45 minutes autoclaving is cidal for both vegetative organisms and endospores |
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Term
| 5) State whether or not boiling is an effective means of sterilization and indicate why |
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Definition
| - No it is not an effective means of sterilization. Boiling water will kill vegetative cells after about 10 minutes but certain viruses may survive up to 30 minutes and certain endospores may survive hours in boiling water |
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Term
| 6) State two methods of applying dry heat |
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Definition
| - Hot air sterilization and incineration |
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Term
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Definition
| - Mild heating of milk and other materials to kill particular spoilage organisms or pathogens. It does not kill all organisms |
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Term
| 8) State whether low temperature has a static or cidal effect on microorganisms and indicate why |
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Definition
| - Low temperature has a static effect because it slows down microbial metabolism |
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Term
| 9) State whether desiccation has a static or a cidal effect on microorganisms and indicate how it affects the cell |
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Definition
| - Desiccation has a static effect lack of water inhibits the action of microbial enzymes. |
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Term
| Describe osmosis in terms of water flow through a semipermeable membrane |
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Definition
| - Osmosis is when water flows through a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration |
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Term
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Definition
| - When the area or cell has a higher solute concentration than the area it is in or the cell which is in it. |
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Term
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Definition
| - Shrinkage of the cytoplasmic membrane due to water leaving the cell and going into the hypertonic solution surrounding the cell |
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Term
| 12) Describe how bacterial growth is inhibited in jams and salt-cured meats |
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Definition
| - When bacteria is in jams or salt cured meats it is inhibited due to hypertonicity |
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Term
| 13) State whether hypertonicity has a static or a cidal effect on microorganisms |
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Definition
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Term
| 14) State how the wavelength and the length of exposure influence the bacteriocidal effect of UV light |
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Definition
- 260nm – 270 nm is the most cidal wavelengths of UV light this is where it is absorbed by the nucleic acid
- The longer the length of exposure the greater the effect |
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Term
| 15) Describe specifically how UV light kills microorganisms |
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Definition
| - UV light is absorbed by microbial DNA and causes adjacent thymine bases on the same DNA strand to covalently bond together forming what are called thymine-thymine dimmers, when the DNA tries to replicate it cant and DNA replication is terminated. |
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Term
| 16) State why UV light is only useful as a means of controlling surface contaminants and give several practical applications |
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Definition
- UV light has very poor penetrating power.
- Used in hospital operating rooms and sinks , in aseptic filling rooms of pharmaceutical companies, in microbiological hoods and in the processing equipment used by the food and dairy industries |
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Term
| 17) State the concept behind sterilizing solutions with micropore membrane filters |
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Definition
| - Filter contains pores small enough to prevent the passage of microbes but large enough to allow the organism- free fluid to pass through. t |
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Term
| 18) State why filters are preferred over autoclaving for such materials as vaccines, antibiotic solutions, sera, and enzyme solutions |
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Definition
| - with autoclaving they may be damaged or denatured by high temperatures or chemical agents. |
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Term
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Definition
| - The process of destroying all liing organisms and viruses |
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Term
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Definition
| - The elimination of harmful microorganisms, but not necessarily endospores, from inanimate objects and surfaces |
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Term
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Definition
| - Agent used to disinfect inanimate objects but generally too toxic to use on human tissues |
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Term
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Definition
| - Agent that kills or inhibits growth of microbes but is safe to use on human tissue |
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Term
| 2) State why chemical agents are usually unreliable for sterilization |
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Definition
| - They work slowly on some viruses |
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Term
| 3) Describe two modes of action of disinfectants, antiseptics and sanitizers i.e. how they harm the microorganisms |
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Definition
- Damage the lipids and/or proteins of the semi permeable cytoplasmic membrane of microorganisms resulting in leakage of cellular materials needed to sustain life
- Denature microbial enzymes and other proteins usually by disrupting the hydrogen and disulfide bonds that give the protein its three dimensional functional shape. This block metabolism |
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Term
| 4) State why the results of an in vitro test to evaluate chemical agents may not necessarily apply to in vivo situations |
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Definition
| - In vitro test is done under artificial controlled laboratory conditions. An in vivo test is done under the actual conditions of normal use |
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Term
| 5) Define transient flora and resident flora and compare the two groups in terms of ease of removal |
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Definition
| - Resident flora are the normal flora of the skin. Transient flora are the microorganism you pick up from what you have been handling. Transient flora can be removed. Resident flora can be reduced but not removed easily. |
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Term
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Definition
| - Substances produced as metabolic products of one microorganism which inhibit or kill other microorganisms |
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Term
| b. Antimicrobial chemotherapeutic chemical |
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Definition
| - Chemicals synthesized in the laboratory which can be used therapeutically on microorganisms |
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Term
| c. Narrow-spectrum antibiotic |
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Definition
| - Only effective against gram negative bacteria or only a few species |
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Term
| d. Broad- spectrum antibiotic |
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Definition
| - Effective against variety of both gram positive and gram negative bacteria |
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Term
| 7) Discuss the meaning of selective toxicity in terms of antimicrobial chemotherapy |
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Definition
| - Agent used must inhibit or kills the microorganism in question without seriously harming the host |
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Term
| 8) State why antimicrobial susceptibility testing is often essential in choosing the proper chemotherapeutic agent to use in treating an infection |
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Definition
| - It determines which antibiotic will be the best to use |
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Term
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Definition
| - Unicellular eukaryotic microorganisms belonging to the kingdom protista |
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Term
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Definition
| - The vegetative form of a protozoan |
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Term
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Definition
| - Protective form of protozoans produced under certain conditions |
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Term
| 2) State what causes the recurring fever of malaria |
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Definition
| - Result of the lysis of the infected red blood cells casuing release of merozoites and their metabolic by products |
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Term
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Definition
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Term
| - Multicellular, often macroscopic worms having both rudimentary organs and organ systems |
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Definition
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Term
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Definition
| - Contain both male and female sexual organs |
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Term
| 5) List the three classes of parasitic helminths and state the common name for each class. |
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Definition
- Nematodes - roundworms
- Cestodes - Tapeworms
- Trematodes - Flukes |
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Term
| 6) State how the following diseases may be transmitted to humans and state how each disease may be diagnosed in the clinical laboratory:ascariasis |
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Definition
- Transmited by ingesting water or food contaminated with feces that contains Ascaris ova or from fingers contaminated with polluted soil
- Diagnosed by microscopically looking for Ascaris ova in a fecal smear |
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Term
| 6) State how the following diseases may be transmitted to humans and state how each disease may be diagnosed in the clinical laboratory:pinworms |
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Definition
- Transmitted by inhaling E. vermicularis ova or from transfer of ova to the mouth from fecally contaminated finger
- Diagnosed by applying tape to perianal region and microscopically looking for pinworm ova that have stuck to the tape |
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Term
| 6) State how the following diseases may be transmitted to humans and state how each disease may be diagnosed in the clinical laboratory:trichinosis |
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Definition
- Transmitted mainly by eating poorly cooked infected porl containing encysted larva 1-2 mm long
- Diagnosed by serological tests and microscopic examination of biopsy specimens |
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Term
| 6) State how the following diseases may be transmitted to humans and state how each disease may be diagnosed in the clinical laboratory: tapeworms |
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Definition
- Transmitted by eating poorly cooked infected beef, prok or fish containing cysticerci
- Diagnosed by looking for proglottids and ova in the feces |
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Term
| 6) State how the following diseases may be transmitted to humans and state how each disease may be diagnosed in the clinical laboratory: flukes |
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Definition
| - Transmitted by ingesting poorly cooked fish, crayfish, crabs, snails or water vegetables infested with flukes |
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Term
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Definition
Cyst of Entamoeba histolytica in a fecal smear |
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Term
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Definition
Trypanosoma gambiense in a blood smear |
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Term
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Definition
Giardia lamblia in a fecal smear |
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Term
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Definition
Trichomonas vaginalis in vaginal discharge |
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Term
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Definition
Balantidium coli in a fecal smear |
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Term
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Definition
Sporozoites of Plasmodium (arrows) from the salivary glands of an infected mosquito |
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Term
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Definition
Plasmodium vivax infecting red blood cells |
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Term
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Definition
Ova of Ascaris lumbricoides |
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Term
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Definition
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Term
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Definition
Ova of Enterobius vermicularis (pinworm |
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Term
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Definition
Enterobius vermicularis (pinworm) filled with ova |
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Term
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Definition
Trichinella spiralis Encysted in Muscle Tissue |
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Term
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Definition
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Term
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Definition
The Tapeworm Taenia pisiformis (Cestode) |
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Term
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Definition
Gravid Proglottis of theTapeworm Taenia pisiformis (Cestode) |
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Term
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Definition
The Liver Fluke Fasciola hepatica (trematode) |
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Term
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Definition
The Blood Fluke Schistosoma (Trematode) |
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