MCQOPTIONS
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MCQOPTIONS
This section includes 105 Mcqs, each offering curated multiple-choice questions to sharpen your Microbiology knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
Which of the following is not a physical method for selection of pure culture? |
| A. | Heat treatment |
| B. | pH of the media |
| C. | Cell size and motility |
| D. | Use of dilute media |
| Answer» E. | |
| 52. |
Organic molecules that increase the rate of metabolic reactions with themselves changing are known as |
| A. | coenzymes |
| B. | enzymes |
| C. | substrates |
| D. | reactants |
| Answer» C. substrates | |
| 53. |
The active form of enzyme is |
| A. | apoenzyme |
| B. | coenzyme |
| C. | holoenzyme |
| D. | none of these |
| Answer» D. none of these | |
| 54. |
Which of the following is an abiotic elicitors? |
| A. | UV irradiation |
| B. | Osmotic shock |
| C. | Heavy metal ions |
| D. | All of these |
| Answer» E. | |
| 55. |
In the pour plate method, the mixed culture is diluted directly in tubes of |
| A. | liquid agar medium |
| B. | sterile liquid usually water |
| C. | both (a) and (b) |
| D. | none of these |
| Answer» B. sterile liquid usually water | |
| 56. |
Important example(s) of enriched medium/media is/ are |
| A. | Loeffler's serum slope |
| B. | Bordet-gengou medium |
| C. | Blood agar |
| D. | All of these |
| Answer» E. | |
| 57. |
Main function of an enzyme is to |
| A. | increase the activation energy |
| B. | decrease the activation energy |
| C. | maintain constant activation energy |
| D. | none of these |
| Answer» C. maintain constant activation energy | |
| 58. |
Which of the following problem makes it impossible to satisfy all of Koch's postulates? |
| A. | Microorganism causes serious symptoms in humans |
| B. | Microorganism cannot be isolated in pure culture |
| C. | Species of microorganism is in question |
| D. | Genes from the microorganism cannot be amplified by PCR |
| Answer» C. Species of microorganism is in question | |
| 59. |
Isolation of pure culture refers to ___________ |
| A. | purification of culture |
| B. | introduction of inoculum |
| C. | separation of a single colony |
| D. | to grow microorganisms on a surface |
| Answer» D. to grow microorganisms on a surface | |
| 60. |
Which of the following bacteria can grow in alkaline pH? |
| A. | Shigella |
| B. | Lactobacilli |
| C. | Salmonella |
| D. | Vibrio cholerae |
| Answer» E. | |
| 61. |
The inactive organic molecular portion of enzyme is |
| A. | apoenzyme |
| B. | coenzyme |
| C. | holoenzyme |
| D. | none of these |
| Answer» C. holoenzyme | |
| 62. |
The protoplast can be used to |
| A. | modify genetic information |
| B. | create plant hybrid |
| C. | study plant viral infections |
| D. | all of these |
| Answer» E. | |
| 63. |
Cell size and cell number can be measured using |
| A. | hemocytometer |
| B. | coulter counter |
| C. | petroff-hausser counting chamber |
| D. | none of these |
| Answer» C. petroff-hausser counting chamber | |
| 64. |
Many enzymes consists of a protein combined with low molecular weight organic molecule called as |
| A. | apoenzyme |
| B. | co-enzyme |
| C. | holoenzyme |
| D. | co-factors |
| Answer» C. holoenzyme | |
| 65. |
Which of the following is used for the proper maintenance and preservation of pure cultures? |
| A. | Periodic transfer to fresh media |
| B. | Preservation by overlaying cultures with mineral oil |
| C. | Preservation by lyophilization |
| D. | All of the above |
| Answer» E. | |
| 66. |
The solidifying agent commonly used in preparation of media is/are |
| A. | agar |
| B. | silica gel |
| C. | both (a) and (b) |
| D. | none of these |
| Answer» D. none of these | |
| 67. |
In the process of freeze drying, a dense cell suspension is placed in small vials and is frozen at |
| A. | -60 to -78°C |
| B. | -20 to -30°C |
| C. | -30 to -48°C |
| D. | -48 to -58°C |
| Answer» B. -20 to -30°C | |
| 68. |
Which of the following bacteria can grow in acidic pH? |
| A. | Vibrio cholerae |
| B. | Lactobacilli |
| C. | Shigella |
| D. | Salmonella |
| Answer» C. Shigella | |
| 69. |
A dead cell does not contribute to turbidity in the culture medium. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 70. |
How many cells present per millilitre in a bacterial culture can make the culture turbid? |
| A. | cell |
| B. | 000 cells |
| C. | lakh cells |
| D. | 07-108 cells |
| Answer» E. | |
| 71. |
Which of the following method is used for enumeration of bacteria in vaccines and cultures? |
| A. | Microscopic Count |
| B. | Membrane filter |
| C. | Plate count |
| D. | Dry weight determination |
| Answer» B. Membrane filter | |
| 72. |
Which of the following is a direct measurement of growth? |
| A. | Determination of nitrogen content |
| B. | Turbidimetric methods |
| C. | Determination of Dry weight of cells |
| D. | Measurement of a specific chemical change produced on a constituent of the medium |
| Answer» D. Measurement of a specific chemical change produced on a constituent of the medium | |
| 73. |
Stringent anaerobes can be grown in a media by taking special measure as |
| A. | boiling the media for several minutes |
| B. | addition of cysteine |
| C. | passing through oxygen-free nitrogen |
| D. | any of these |
| Answer» E. | |
| 74. |
Radical shifts in pH can be prevented by incorporating |
| A. | a buffer |
| B. | an oxidizing agent |
| C. | a reducing agent |
| D. | any of these |
| Answer» B. an oxidizing agent | |
| 75. |
Colony-forming units per ml is the unit of _____________ |
| A. | Microscopic count |
| B. | Electronic enumeration |
| C. | Plate count |
| D. | Turbidimetric measurement |
| Answer» D. Turbidimetric measurement | |
| 76. |
A disease producing species occurring in a mixed culture can often be selected on the basis of its |
| A. | pathogenic properties |
| B. | special carbon source |
| C. | special nitrogen source |
| D. | none of these |
| Answer» B. special carbon source | |
| 77. |
Agar is used for solidifying culture media because |
| A. | it does not affect by the growth of bacteria |
| B. | it does not add to the nutritive properties of the medium |
| C. | the melting and solidifying points of agar solution are not the same |
| D. | all of the above |
| Answer» E. | |
| 78. |
For the selection of lactobacilli present in cheddar cheese, the pH of the medium is maintained at |
| A. | 6.35 |
| B. | 5.35 |
| C. | 4.35 |
| D. | 5.75 |
| Answer» C. 4.35 | |
| 79. |
Mac-Conkey medium is an example of |
| A. | transport medium |
| B. | enrichment medium |
| C. | differential medium |
| D. | all of these |
| Answer» D. all of these | |
| 80. |
Pseudomonas aeruginosa forms a blue water soluble pigment called |
| A. | pyocyanin |
| B. | chlororaphin |
| C. | pyoverdin |
| D. | β-carotene |
| Answer» B. chlororaphin | |
| 81. |
Which of the following chemotherapeutic agents may affect the growth of Campylobacter jejuni? |
| A. | Vacomycin |
| B. | Polymyxin |
| C. | Trimethoprim |
| D. | None of these |
| Answer» E. | |
| 82. |
To select cholera-causing bacterium, Vibrio cholerae, the pH of the medium is maintained at a pH of |
| A. | 8.5 |
| B. | 8.90 |
| C. | 6.79 |
| D. | 3.5 |
| Answer» B. 8.90 | |
| 83. |
For the selection of endospore-forming bacteria, a mixed culture can be heated at |
| A. | 80°C for 10 minutes |
| B. | 70°C for 10 minutes |
| C. | 60°C for 10 minutes |
| D. | 90°C for 10 minutes |
| Answer» B. 70°C for 10 minutes | |
| 84. |
The concentration of agar to obtain semi solid media is |
| A. | 1.5-20% |
| B. | 0.5% or less |
| C. | >10% |
| D. | >10%but<20% |
| Answer» C. >10% | |
| 85. |
Which of the following bacteria dies quickly after drying? |
| A. | Treponema pallidium |
| B. | Mycobacterium tuberculosis |
| C. | Staphylococcus aureus |
| D. | Pseudomonas aeruginosa |
| Answer» B. Mycobacterium tuberculosis | |
| 86. |
Surface texture of strains are related to virulence. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» B. False | |
| 87. |
Pyoverdin is which type of pigment? |
| A. | water-insoluble pigment |
| B. | water-soluble pigment |
| C. | fluorescent pigment |
| D. | sparingly water-soluble pigment |
| Answer» D. sparingly water-soluble pigment | |
| 88. |
What is the color of colonies of Staphylococcus aureus? |
| A. | Pink |
| B. | Red |
| C. | Violet |
| D. | Gold |
| Answer» E. | |
| 89. |
Which bacteria among the following produces a water-insoluble pigment? |
| A. | Mycobacterium kansasii |
| B. | Pseudomonas aeruginosa |
| C. | Chromobacterium violaceum |
| D. | Pseudomonas chlororaphis |
| Answer» D. Pseudomonas chlororaphis | |
| 90. |
Growth in broth cultures occurs mainly in the form of __________ |
| A. | slightly turbid |
| B. | heavy surface pellicle |
| C. | sediment |
| D. | viscous |
| Answer» C. sediment | |
| 91. |
Which device is used to pick a single bacterial cell from a mixed culture? |
| A. | microscope |
| B. | micropipette |
| C. | microprobe |
| D. | micromanipulator |
| Answer» E. | |
| 92. |
The American Type Culture Collection, located in Rockville, Maryland in the year 1980 has a collection of bacterial strain in what numbers? |
| A. | 10,000 |
| B. | 11,000 |
| C. | 500 |
| D. | 11,500 |
| Answer» E. | |
| 93. |
Nichrome loop wire is used in which of the following techniques? |
| A. | Pour-plate |
| B. | Streak-plate |
| C. | Spread-plate |
| D. | Roll-tube technique |
| Answer» C. Spread-plate | |
| 94. |
The National Collection of Type Cultures is situated in ____________ |
| A. | France |
| B. | England |
| C. | Germany |
| D. | Japan |
| Answer» C. Germany | |
| 95. |
Which of the following has a larger diameter? |
| A. | well-separated colonies |
| B. | crowded colonies |
| C. | young colonies |
| D. | old colonies |
| Answer» B. crowded colonies | |
| 96. |
Which of the following method can be used to determine the number of bacteria quantitatively? |
| A. | Streak-plate |
| B. | Spread-plate |
| C. | Pour plate |
| D. | Pour-plate and spread plate |
| Answer» E. | |
| 97. |
Which of the following are not performed in lyophilization? |
| A. | agar slant is covered with mineral oil |
| B. | cell suspension is frozen at -60 degree to -78 degree C |
| C. | vials are connected to high-vacuum line |
| D. | bacterial sample is dehydrated |
| Answer» B. cell suspension is frozen at -60 degree to -78 degree C | |
| 98. |
Dilution of the mixed culture is a common step in all the three methods: the streak-plate,the spread-plate and the pour-plate technique. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 99. |
What is the temperature of liquid nitrogen? |
| A. | -120 degree C |
| B. | 0 degree C |
| C. | -150 degree C |
| D. | -196 degree C |
| Answer» E. | |
| 100. |
Which of the following is a function of cryoprotective agents? |
| A. | for long-term preservation of cultures |
| B. | prevents cell damage due to ice crystal formation |
| C. | prevents formation of ice |
| D. | to trap the liquid nitrogen |
| Answer» C. prevents formation of ice | |