MCQOPTIONS
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MCQOPTIONS
This section includes 229 Mcqs, each offering curated multiple-choice questions to sharpen your Microbiology knowledge and support exam preparation. Choose a topic below to get started.
| 101. |
The organisms retained in the fluids filtered by Seitz filter is |
| A. | Proteus |
| B. | Staphylococcus |
| C. | Clostridium |
| D. | None of these |
| Answer» E. | |
| 102. |
The effectiveness of heat in killing microorganisms is much greater in _____________ |
| A. | acid |
| B. | alkali |
| C. | neutral |
| D. | acid and alkali |
| Answer» B. alkali | |
| 103. |
Gram-negative organisms are more susceptible to higher concentrations of triphenylmethane dyes. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» B. False | |
| 104. |
The endosymbiosis hypothesis provides an explanation for how |
| A. | eukaryotes developed from prokayotes |
| B. | prokaryotes developed from eukaryotes |
| C. | algae developed from protozoa |
| D. | protozoa developed from algae |
| Answer» B. prokaryotes developed from eukaryotes | |
| 105. |
Which bacteria appears purple-violet colour after staining? |
| A. | Gram-positive |
| B. | Gram-negative |
| C. | Both Gram-positive and Gram-negative |
| D. | Neither Gram-positive nor Gram-negative |
| Answer» B. Gram-negative | |
| 106. |
Gram-positive bacteria are usually more susceptible to? |
| A. | streptomycin |
| B. | tetracyclin |
| C. | penicillin |
| D. | ampicillin |
| Answer» D. ampicillin | |
| 107. |
The dye eosinate of methylene blue belongs to which group? |
| A. | Acidic dye |
| B. | Basic dye |
| C. | Neutral dye |
| D. | Oxazine dye |
| Answer» D. Oxazine dye | |
| 108. |
Which of the following is the example of Gram-negative bacteria? |
| A. | Lactobacillus |
| B. | Eschericia coli |
| C. | Staphylococcus aureus |
| D. | Bacillus subtilis |
| Answer» C. Staphylococcus aureus | |
| 109. |
Which of the staining technique helps in demonstrating spore structure in bacteria as well as free spores? |
| A. | Acid-fast stain |
| B. | Endospore stain |
| C. | Capsule stain |
| D. | Flagella stain |
| Answer» C. Capsule stain | |
| 110. |
The DNA of Klebsiella pneumonia has a moles % G+C content of? |
| A. | 70-71 |
| B. | 50-53 |
| C. | 56-58 |
| D. | 32-35 |
| Answer» D. 32-35 | |
| 111. |
To transfer genes from one species to another, especially useful are |
| A. | vectors only |
| B. | plasmids only |
| C. | double stranded DNA molecules |
| D. | vectors and plasmids |
| Answer» E. | |
| 112. |
Micro-organisms do not include |
| A. | mushrooms |
| B. | molds |
| C. | bacteria |
| D. | fungi |
| Answer» D. fungi | |
| 113. |
Which of the following are characteristics of archaebacterial different from eubacteria? |
| A. | methane-producers |
| B. | extreme halophiles |
| C. | thermoacidophiles |
| D. | methane-producers,extreme halophiles,and thermoacidophiles |
| Answer» E. | |
| 114. |
What are the blood serum proteins produced by animals called? |
| A. | Enzymes |
| B. | Antibodies |
| C. | Amino acids |
| D. | Toxins |
| Answer» C. Amino acids | |
| 115. |
The DNA molecule of microorganisms is made up of base pairs of ________________ |
| A. | guanine-cytosine |
| B. | adenine-thymine |
| C. | adenine-cytosine |
| D. | guanine-cytosine and adenine-thymine |
| Answer» E. | |
| 116. |
According to Bergey’s Manual of Systematic Bacteriology, prokaryotes that lack a cell wall belong to the group? |
| A. | Gracilicutes |
| B. | Firmicutes |
| C. | Tenericutes |
| D. | Mendosicutes |
| Answer» D. Mendosicutes | |
| 117. |
If two organisms are distantly related and show no DNA homology there still may be similarity in their rRNA cistrons. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» B. False | |
| 118. |
Which of the following actions are not affected by antimicrobial agents? |
| A. | cell wall synthesis |
| B. | nucleic acid synthesis |
| C. | protein synthesis |
| D. | capsule formation |
| Answer» E. | |
| 119. |
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. | |
| 120. |
Which among the following come under Gram-positive eubacteria? |
| A. | Clostridium |
| B. | Actinomyces |
| C. | Rhizobium |
| D. | Clostridium,Actinomyces |
| Answer» E. | |
| 121. |
Which of the following agents irreversibly oxidize and inactivate proteins with sulphydral groups? |
| A. | Alcohol |
| B. | Phenol |
| C. | Iodine |
| D. | Chlorine |
| Answer» D. Chlorine | |
| 122. |
Gonococci are inhibited by tryptoflavine in dilutions of ____________________ |
| A. | 1:200,000 |
| B. | 1:300,000 |
| C. | 1:1,000,000 |
| D. | 1:10,000,000 |
| Answer» E. | |
| 123. |
Chloramines are more stable than than hypochlorites. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» B. False | |
| 124. |
Which of the following structure is absent in eukaryotic cells? |
| A. | Mitochondria |
| B. | Chloroplasts |
| C. | Golgi structure |
| D. | Mesosome |
| Answer» E. | |
| 125. |
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 | |
| 126. |
Which of the following sequences has helped in identifying eukaryotes, eubacteria and archeabacterial cell types? |
| A. | Signature sequence |
| B. | Signal sequence |
| C. | Shine-Dalgarno sequence |
| D. | Amino acid sequence |
| Answer» B. Signal sequence | |
| 127. |
Which of the following is the most primitive? |
| A. | Virus |
| B. | Eukaryote |
| C. | Archaeon |
| D. | Mitochondria |
| Answer» D. Mitochondria | |
| 128. |
Two organisms which are very closely related to each other have which of the following property? |
| A. | similar mol% G+C values |
| B. | different mol% G+C values |
| C. | similar mol% G+C values and heteroduplexes are formed. |
| D. | different mol% G+C values and heteroduplexes are not formed. |
| Answer» D. different mol% G+C values and heteroduplexes are not formed. | |
| 129. |
All the following are considered eukaryotes except |
| A. | archaea |
| B. | fungi |
| C. | protozoa |
| D. | humans |
| Answer» B. fungi | |
| 130. |
What are ribosomes composed of? |
| A. | Proteins |
| B. | DNA |
| C. | RNA |
| D. | Proteins and RNA |
| Answer» E. | |
| 131. |
Type strain is used for referring to? |
| A. | species |
| B. | genus |
| C. | family |
| D. | division |
| Answer» B. genus | |
| 132. |
The correct order of taxonomic groups from higher to lower rank is? |
| A. | Kingdom—Order—Class—Family |
| B. | Order—Class—Division—Family—Genus—Species |
| C. | Kingdom—Order—Division—Family—Class—Genus—Species |
| D. | Kingdom—Division—Class—Order—Family—Genus—Species |
| Answer» E. | |
| 133. |
Iodine kills the microorganisms by causing denaturation of proteins. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 134. |
Which of the following is the mode of action of formaldehyde? |
| A. | interference with glycolysis |
| B. | shows oxidizing property |
| C. | combines with vital nitrogen compounds |
| D. | changes the permeability of cytoplasmic membrane |
| Answer» D. changes the permeability of cytoplasmic membrane | |
| 135. |
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. | |
| 136. |
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 | |
| 137. |
A suspension of E.coli exposed to a heat treatment may yield a greater number of survivors if a plating medium of _____________ is used. |
| A. | peptone |
| B. | trypticase soy agar |
| C. | deoxycholate agar |
| D. | potato dextrose |
| Answer» C. deoxycholate agar | |
| 138. |
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 | |
| 139. |
For sterilization of which material gamma rays can be used? |
| A. | Catheters |
| B. | Plastic syringes |
| C. | Canulas |
| D. | None of these |
| Answer» E. | |
| 140. |
In Gram-staining, iodine is used as a______________ |
| A. | fixative |
| B. | mordant |
| C. | solublizer |
| D. | stain |
| Answer» C. solublizer | |
| 141. |
Media containing spores and thermolabile constituents are sterilized by |
| A. | pasteurization |
| B. | UV radiation |
| C. | dry heat |
| D. | tyndalization |
| Answer» C. dry heat | |
| 142. |
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 | |
| 143. |
Liquid water-soluble substances appropriately diluted are dispensed into sterile test tubes, to which are added a measured amount of the test organism and then this is transferred into tubes of sterile media.This method helps in determining _____________________ |
| A. | whether the inhibitory action is bactericidal |
| B. | whether the inhibitory action is bacteristatic |
| C. | decrease in the amount of growth |
| D. | complete absence of growth |
| Answer» B. whether the inhibitory action is bacteristatic | |
| 144. |
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 | |
| 145. |
An agent that prevents the growth of bacteria are known as __________________ |
| A. | Bactericide |
| B. | Bacteriostatic |
| C. | Antimicrobial |
| D. | Antibiotic |
| Answer» C. Antimicrobial | |
| 146. |
Gram staining was introduced by |
| A. | Christian gram |
| B. | Alfred Gram |
| C. | Robertcook |
| D. | Louis Pasteur |
| Answer» B. Alfred Gram | |
| 147. |
All of the following are sporicidal except |
| A. | glutaraldehyde |
| B. | ethylene oxide |
| C. | formaldehyde |
| D. | alcohol |
| Answer» E. | |
| 148. |
The foundation for the germ theory of disease was set down by |
| A. | Robert Koch |
| B. | Ronald Ross |
| C. | Louis Pasteur |
| D. | Walter Reed |
| Answer» D. Walter Reed | |
| 149. |
Which of the following is considered the most unifying concept in biology? |
| A. | Taxonomy |
| B. | Anatomy |
| C. | Genetics |
| D. | Evolution |
| Answer» E. | |
| 150. |
Total Magnification is obtained by__________ |
| A. | Magnifying power of the objective lens |
| B. | Magnifying power of eyepiece |
| C. | Magnifying power of condenser lens |
| D. | Magnifying power of both the objective lens and eyepiece |
| Answer» E. | |