MCQOPTIONS
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MCQOPTIONS
This section includes 50 Mcqs, each offering curated multiple-choice questions to sharpen your Microbiology knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
If a 1:600 dilution of a test compound kills a standard population of in 10 minutes but not 5 minutes while a 1:60 dilution of phenol kills the population in the same time, what is the phenol coefficient of the test compound? |
| A. | 1 |
| B. | 5 |
| C. | 10 |
| D. | 50 |
| Answer» D. 50 | |
| 2. |
Which disinfectant was the most effective against "? |
| A. | Phenol |
| B. | Cetylpyridinium chloride |
| C. | Hexachlorophene |
| D. | Merthiolate |
| Answer» E. | |
| 3. |
Which disinfectant would be most effective against found in a blood spill? |
| A. | Phenol |
| B. | Cetylpyridinium chloride |
| C. | Hexachlorophene |
| D. | None of these |
| Answer» E. | |
| 4. |
The time required to kill 90% of the microorganisms in a sample at a specific temperature is the |
| A. | decimal reduction time |
| B. | thermal death point |
| C. | F value |
| D. | D value |
| Answer» E. | |
| 5. |
Which of the following articles can be sterilized in an autoclave? |
| A. | Gloves |
| B. | Culture media |
| C. | Dressing material |
| D. | All of these |
| Answer» E. | |
| 6. |
Which of the following disinfectants act by disrupting microbial membranes? |
| A. | Cationic detergents |
| B. | Halogens |
| C. | Heavy metals |
| D. | Aldehydes |
| Answer» B. Halogens | |
| 7. |
Which of the following is best to sterilize heat labile solutions? |
| A. | Dry heat |
| B. | Autoclave |
| C. | Membrane filtration |
| D. | Pasteurization |
| Answer» D. Pasteurization | |
| 8. |
Which of the following is best used for long term storage of microbial samples when carried out properly? |
| A. | Storage in a freezer at -10 C |
| B. | Storage in a freezer at ultra low temperatures (-70 C) |
| C. | Storage in a refrigerator on an agar slant |
| D. | Storage on a petri plate at room temperature |
| Answer» C. Storage in a refrigerator on an agar slant | |
| 9. |
Which of the following compounds are commonly used as general antiseptics to treat cuts and scratches? |
| A. | Aldehydes |
| B. | Ethylene oxide |
| C. | Halogens |
| D. | None of these |
| Answer» D. None of these | |
| 10. |
Which of the following is a limitation of the autoclave? |
| A. | It takes too long to sterilize |
| B. | It lacks the ability to inactivate viruses |
| C. | It lacks the ability to kill endospores |
| D. | It will destroy heat labile materials |
| Answer» E. | |
| 11. |
Which of the following has most heat resistant spores? |
| A. | <i>Clostridium histolyticum</i> |
| B. | <i>Clostridium perfringens </i> |
| C. | <i>Bacillus stearothermophilus</i> |
| D. | <i> Bacillus cereus</i> |
| Answer» D. <i> Bacillus cereus</i> | |
| 12. |
The lowest temperature that kills all microorganisms in a liquid suspension in 10 minutes is known as the |
| A. | decimal reduction time |
| B. | thermal death point |
| C. | thermal death temperature |
| D. | thermal death time |
| Answer» C. thermal death temperature | |
| 13. |
Which of the following tests is designed to simulate the natural conditions under which the disinfectants are used in hospitals? |
| A. | Phenol coefficient test |
| B. | Minimum inhibitory concentration test |
| C. | Capacity test |
| D. | None of these |
| Answer» D. None of these | |
| 14. |
Which of the following was the first widely used antiseptic and disinfectant? |
| A. | Chlorine |
| B. | Phenol |
| C. | Iodine |
| D. | Alcohol |
| Answer» C. Iodine | |
| 15. |
Steam exposure of a material at 100 C for 20 minutes for three consecutive days is known as |
| A. | inspissation |
| B. | tyndallization |
| C. | autoclaving |
| D. | none of these |
| Answer» C. autoclaving | |
| 16. |
The organisms retained in the fluids filtered by Seitz filter is |
| A. | <i>Proteus</i> |
| B. | <i>Staphylococcus</i> |
| C. | <i>Clostridium</i> |
| D. | None of these |
| Answer» E. | |
| 17. |
For sterilization of which material gamma rays can be used? |
| A. | Catheters |
| B. | Plastic syringes |
| C. | Canulas |
| D. | None of these |
| Answer» E. | |
| 18. |
The time in minutes at a specific temperature needed to kill a population of cells is the |
| A. | decimal reduction time |
| B. | thermal death point |
| C. | thermal death temperature |
| D. | F value |
| Answer» E. | |
| 19. |
Which of the following is sterilized with the help of glutaraldehyde? |
| A. | Thermometers |
| B. | Bronchoscopes |
| C. | Cystoscopes |
| D. | All of these |
| Answer» E. | |
| 20. |
Microbes can be removed from a liquid solution by the process of |
| A. | filtration |
| B. | freeze-drying |
| C. | osmosis |
| D. | desiccation |
| Answer» B. freeze-drying | |
| 21. |
Which of the following process can be efficiently carried out by incineration? |
| A. | Sterilization of scalpel blades and needles |
| B. | Sterilization of all glass syringes |
| C. | Sterilization of points of forceps |
| D. | Destruction of contaminated materials |
| Answer» E. | |
| 22. |
The process of making an object free from living organisms including bacterial and fungal spores and viruses is known as |
| A. | pasteurization |
| B. | antisepsis |
| C. | disinfection |
| D. | sterilization |
| Answer» E. | |
| 23. |
Media containing spores and thermolabile constituents are sterilized by |
| A. | pasteurization |
| B. | UV radiation |
| C. | dry heat |
| D. | tyndalization |
| Answer» C. dry heat | |
| 24. |
A(n)____is used to prevent infection by killing or inhibiting pathogen growth on animal tissues. |
| A. | bacteriostatic agent |
| B. | sanitizer |
| C. | disinfectant |
| D. | antiseptic |
| Answer» E. | |
| 25. |
One drawback to the use of ultraviolet light as a sterilizing agent is its |
| A. | failure to kill bacteria |
| B. | failure to bacterial spores |
| C. | failure to kill microbes in a closed environment |
| D. | failure to kill microbes located in the center of an object |
| Answer» E. | |
| 26. |
Ethylene oxide is used to destroy or kill which of the following microbes? |
| A. | Bacteria |
| B. | Spores |
| C. | Fungi |
| D. | All of these |
| Answer» E. | |
| 27. |
Bactericidal concentration of phenol is |
| A. | 0.25% |
| B. | 0.5% |
| C. | 0.75% |
| D. | 1% |
| Answer» E. | |
| 28. |
Which of the following skin disinfectant(s) is/are most frequently used? |
| A. | Isopropyl alcohol |
| B. | Ethyl alcohol |
| C. | Both (a) and (b) |
| D. | none of these |
| Answer» D. none of these | |
| 29. |
Preservation of foods by using salts and sugars works by |
| A. | raising pH |
| B. | lowering osmotic pressure |
| C. | creating a hypertonic environment |
| D. | creating a hypotonic environment |
| Answer» D. creating a hypotonic environment | |
| 30. |
Which of the following items could be sterilized by dry heat sterilization? |
| A. | Intravenous (IV) solution |
| B. | Plastic IV bags |
| C. | Glass pipettes |
| D. | rubber gloves |
| Answer» D. rubber gloves | |
| 31. |
Which of the following does not kill endospores? |
| A. | Autoclave |
| B. | Incineration |
| C. | Hot air sterilization |
| D. | Pasteurization |
| Answer» E. | |
| 32. |
Which of the following describes the effect of ionizing radiation on microbes? |
| A. | Changes the 3-dimensional structure of proteins to a 2-dimen-sional form |
| B. | Substantially decreases enzymatic activity, slowing microbial reproduction |
| C. | Induces electrons and protons to jump out of the molecules of the microbe |
| D. | None of the above |
| Answer» D. None of the above | |
| 33. |
Which is the most important surface active disinfectants? |
| A. | Amphoteric compounds |
| B. | Cationic compounds |
| C. | Non-ionic compounds |
| D. | Anionic compounds |
| Answer» C. Non-ionic compounds | |
| 34. |
Milk is pasteurized in batch method by keeping it at |
| A. | 63 C for 30 minutes |
| B. | 72 C for 60 seconds |
| C. | 73 C for 30 minutes |
| D. | 72 C for 6 minutes |
| Answer» B. 72 C for 60 seconds | |
| 35. |
Which disinfectant was the most effective against Salmonella"? |
| A. | Phenol |
| B. | Cetylpyridinium chloride |
| C. | Hexachlorophene |
| D. | Merthiolate |
| Answer» E. | |
| 36. |
If a canning procedure is not properly followed, which type of microbe is most likely to grow in the canned food? |
| A. | Obligate Aerobe |
| B. | Acidophile |
| C. | Mesophile |
| D. | Obligate Anaerobe |
| Answer» E. | |
| 37. |
Which of the following is not a disinfectant containing a heavy metal? |
| A. | Silver nitrate |
| B. | Mercurochrome |
| C. | Copper sulfate |
| D. | Chlorine |
| Answer» E. | |
| 38. |
Which disinfectant would be most effective against Staphylococcus found in a blood spill? |
| A. | Phenol |
| B. | Cetylpyridinium chloride |
| C. | Hexachlorophene |
| D. | None of these |
| Answer» E. | |
| 39. |
Complete destruction of the microorganisms is commonly known as |
| A. | disinfection |
| B. | sterilization |
| C. | antisepsis |
| D. | none of these |
| Answer» D. none of these | |
| 40. |
Which of the following material is sterilized by use of red heat? |
| A. | Soiled dressings |
| B. | Inoculating wires and loops |
| C. | Glass slides |
| D. | All-glass syringes |
| Answer» C. Glass slides | |
| 41. |
Which of the following methods will not sterilize? |
| A. | Aqueous glutaraldehyde for 10 hours |
| B. | Dry heat at 171 C for 1 to 2 hours |
| C. | 121 C at 15 lb/in pressure for 15 to 20 minutes |
| D. | 100 C boiling water for 30 minutes |
| Answer» E. | |
| 42. |
Which of the following is/are vapour-phase disinfectant/s? |
| A. | Formaldehyde |
| B. | Ethylene oxide |
| C. | Both (a) and (b) |
| D. | None of these |
| Answer» D. None of these | |
| 43. |
Sweet and salty foods frequently don't require refrigeration to prevent spoilage because they have |
| A. | insufficient nutrients |
| B. | low pH |
| C. | high concentration of solutes |
| D. | toxic alkaline chemicals |
| Answer» D. toxic alkaline chemicals | |
| 44. |
Iodophores are mixture of |
| A. | iodine and aldehydes |
| B. | iodine and surface active agents |
| C. | iodine and alcohols |
| D. | iodine and phenols |
| Answer» C. iodine and alcohols | |
| 45. |
If a 1:600 dilution of a test compound kills a standard population of Staphylococcus aureus in 10 minutes but not 5 minutes while a 1:60 dilution of phenol kills the population in the same time, what is the phenol coefficient of the test compound? |
| A. | 1 |
| B. | 5 |
| C. | 10 |
| D. | 50 |
| Answer» D. 50 | |
| 46. |
Which of the following substances can sterilize? |
| A. | Alcohol |
| B. | Cetylpyridinium chloride |
| C. | Ethylene oxide |
| D. | Chlorine |
| Answer» D. Chlorine | |
| 47. |
Which of the following is most effective for sterilizing mattresses and plastic petri plates? |
| A. | Chlorine |
| B. | Ethylene oxide |
| C. | Glutaraldehyde |
| D. | Ultraviolet radiation |
| Answer» C. Glutaraldehyde | |
| 48. |
All of the following are sporicidal except |
| A. | glutaraldehyde |
| B. | ethylene oxide |
| C. | formaldehyde |
| D. | alcohol |
| Answer» E. | |
| 49. |
Which of the following is bactericidal? |
| A. | Membrane filtration |
| B. | Ionizing radiation |
| C. | Freeze-drying |
| D. | Deep freezing |
| Answer» C. Freeze-drying | |
| 50. |
Which of the following material is sterilized by heating at 160 C in a hot air oven for one hour? |
| A. | Swab sticks |
| B. | All-glass syringes |
| C. | Oils and jellies |
| D. | All of these |
| Answer» E. | |