5000 Plus MCQs for Lab Technician and Technologists are designed to test the knowledge and proficiency of laboratory professionals who work in the field of clinical laboratory science. These questions cover a wide range of topics related to laboratory science, including anatomy, physiology, microbiology, chemistry, and hematology.
1551 to 1600 MCQs for Lab Technician and Technologist Exam Preparation
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Questions 1551 to 1600
In light microscopes, what function does a condenser serve?
- a) Increases light intensity
- b) Focuses the light rays on the sample
- c) Reduces glare
- d) Focuses the light rays onto our eyes
- e) Magnifies the light rays after their passage through the sample
The order of reagents used in the Gram stain are:
- a) Crystal violet, iodine, alcohol, safranin
- b) Alcohol, crystal violet, iodine, safranin
- c) Crystal violet, safranin, alcohol, iodine
- d) Crystal violet, iodine, safranin, alcohol
- e) Iodine, crystal violet, safranin, alcohol
The compound light microscope can be used to observe:
- a) Bacteria, cell organelles, and red blood cells
- b) Amino acids, bacteria, and red blood cells
- c) Ribosomes, bacteria, cell organelles, and red blood cells
- d) Atoms, proteins, viruses, and bacteria
- e) Viruses, bacteria, cell organelles, and red blood cells
All of the following are examples of special stains except:
- a) Flagellar stain
- b) Ziehl-Neelsen acid-fast stain
- c) Negative stains
- d) Endospore stain
Which of the following statements is most correct about the differential Gram stain?
- a) Acetone/Alcohol differentially destains Gram negative cells.
- b) Crystal violet differentially stains Gram positive cells.
- c) Safranin differentially stains Gram negative cells.
- d) Gram’s iodine differentially stains Gram positive cells.
The total magnification of a microscope is calculated by:
- a) The objective lens power squared
- b) Multiplication of the objective lens and ocular lens magnification powers
- c) Multiplication of the objective lens and condenser lens magnification powers
- d) Addition of the objective lens and ocular lens magnification powers
Which of the following stains is used to classify microorganisms based on their cell wall content?
- a) Gram stain
- b) Methylene blue
- c) Capsular stain
- d) Spore stain
- e) Negative stain
Which of the following microscopic techniques provide three-dimensional images of a bacterial cell?
- a) Dark-field microscopy
- b) Fluorescent microscopy
- c) Transmission electron microscopy
- d) Scanning electron microscopy
Each of the following statements concerning Mycobacterium tuberculosis is correct EXCEPT:
- a) M. tuberculosis appears as a red rod in Gram-stained specimens.
- b) After being stained with carbolfuchsin, M. tuberculosis resists decolorization with acid alcohol.
- c) M. tuberculosis has a large amount of mycolic acid in its cell wall.
- d) M. tuberculosis appears as a red rod in acid-fast stained specimens.
Which of the following is defined as the ability to distinguish or separate two adjacent objects or points from one another in a microscopic specimen?
- a) Reflection
- b) Illuminate
- c) Image
- d) Resolving power
- e) Refraction
The presence of a capsule around bacterial cells usually indicates their increased disease-causing potential and resistance to disinfection. Capsules are generally viewed by:
- a) Scanning electron microscopy
- b) Negative staining
- c) Ziehl-Neelsen staining
- d) Gram staining
Drumstick appearance in the microscopy is the distinguishing characteristic of:
- a) Clostridium tetani
- b) Clostridium perfringens
- c) Clostridium difficile
- d) Clostridium botulinum
What type of microscopy allows for the visualization of internal components within live, unstained specimens?
- a) Phase-contrast
- b) Fluorescence
- c) Electron
- d) Bright-field
- e) Dark-field
Transmission electron microscopy is best for high magnification viewing of:
- a) Surface structure of fixed cells
- b) Surface membranes of live, motile cells
- c) Internal structure of live, motile cells
- d) Internal structure of fixed cells
Your patient is a 30-year-old woman with nonbloody diarrhea for the past 14 hours. Which one of the following organisms is LEAST likely to cause this illness?
- a) Clostridium difficile
- b) Salmonella enteritidis
- c) Streptococcus pyogenes
- d) Shigella dysenteriae
Each of the following agents is a recognized cause of diarrhea EXCEPT:
- a) Enterococcus faecalis
- b) Escherichia coli
- c) Clostridium perfringens
- d) Vibrio cholerae
Which one of the following organisms that infects the gastrointestinal tract is the MOST frequent cause of bacteremia?
- a) Salmonella typhi
- b) Pyrazinamide
- c) Streptomycin
- d) Rifampicin
Which one of the following bacteria has the LOWEST 50% infectious dose (ID50)?
- a) Campylobacter jejuni
- b) Shigella sonnei
- c) Salmonella typhi
- d) Vibrio cholerae
A family has diarrhea after eating raw shellfish due to an oxidase positive, gram-negative curved bacillus that requires a special media for growth. Which of the following is the most likely cause?
- a) Staphylococcus aureus
- b) Clostridium botulinum
- c) Escherichia coli
- d) Vibrio parahaemolyticus
A 26-year-old male with AIDS presents with painful bloody diarrhea. Stool culture on MacConkey agar medium and subsequent analyses reveals predominantly a gram-negative facultative anaerobic rod, which is oxidase negative, lactose negative, H2S negative and non-motile. Which of the following is the most likely cause of this infection?
- a) Shigella flexneri
- b) Vibrio cholerae
- c) Enterobacter aerogenes
- d) Enterotoxigenic Escherichia coli
- e) Salmonella enteritidis
Which of the following pathogenic bacteria is MOST COMMONLY associated with traveler’s diarrhea?
- a) Shigella sonnei
- b) Salmonella typhimurium
- c) Yersinia enterocolitica
- d) Escherichia coli ETEC (enterotoxigenic)
- e) Campylobacter jejuni
Diarrhea associated with prolonged antibiotic treatment, including pseudomembranous colitis, is MOST FREQUENTLY caused by:
- a) Yersinia enterocolitica
- b) Salmonella enteritidis
- c) Clostridium difficile
- d) Shigella dysenteriae
- e) Rota Virus
A 25-year-old female medical student reports that she had lunch at an Indian restaurant in the afternoon. She presents in the emergency department with complaints of abdominal cramps, nausea, and vomiting. Culture and gram stain reveal gram-positive aerobic rods. Which of the following is the most likely cause of this infection?
- a) Staphylococcal food poisoning
- b) Bacillus cereus food poisoning
- c) Clostridium perfringens food poisoning
- d) Clostridium botulinum food poisoning
A specimen suspected of containing members of the Enterobacteriaceae was subjected to a few laboratory diagnostic tests and generated the following results: Gram-negative rod; colorless/pale colonies on MacConkey agar. All of the following microorganisms may be included in the diagnosis, EXCEPT:
- a) Shigella spp
- b) Salmonella spp
- c) Both Salmonella and Shigella
- d) Escherichia coli
Five hours after eating reheated rice at a restaurant, a 24-year-old woman and her husband both developed nausea, vomiting, and diarrhea. Which one of the following organisms is the MOST likely to be involved?
- a) Bacillus cereus
- b) Salmonella typhi
- c) Clostridium perfringens
- d) Enterotoxigenic Escherichia coli
A 29-year-old man with a long history of heartburn and dyspepsia presents to the primary care doctor with severe mid-epigastric pain. He was initially treated with an H2 blocker twice a day. He immediately had relief but his symptoms returned after two weeks. What is the most likely cause for the relapse in his symptoms?
- a) Outlet obstruction due to fibrous tissue repair
- b) Giardia lamblia infection
- c) Helicobacter pylori infection
- d) Acute gastric ulcerations
- e) Tapeworm infestation
For which one of the following enteric illnesses is a chronic carrier state MOST likely to develop?
- a) Campylobacter enterocolitis
- b) Shigella enterocolitis
- c) Cholera
- d) Typhoid fever
The pathogenesis of which one of the following organisms is MOST likely to involve invasion of the intestinal mucosa?
- a) Enterotoxigenic Escherichia coli
- b) Clostridium botulinum
- c) Shigella sonnei
- d) Vibrio cholerae
A 70-year-old man underwent bowel surgery for colon cancer 3 days ago. He now has a fever and abdominal pain. The attending physician is concerned that he may have peritonitis. Which one of the following pairs of organisms is MOST likely to be the cause?
- a) Bordetella pertussis and Salmonella enteritidis
- b) Clostridium botulinum and Shigella dysenteriae
- c) Actinomyces israelii and Campylobacter jejuni
- d) Bacteroides fragilis and Klebsiella pneumoniae
Which one of the following host defense mechanisms is the MOST important for preventing dysentery caused by Salmonella?
- a) Salivary enzymes
- b) Normal flora of the mouth
- c) Alpha interferon
- d) Gastric acid
The following organisms are recognized causes of diarrhea EXCEPT:
- a) Salmonella
- b) Rotavirus
- c) Enterovirus
- d) Campylobacter
- e) Enterobacter
A local day care center has several simultaneous cases of diarrhea. A methylene blue fecal smear was taken during the outbreak from one of the children and revealed numerous PMN’s and occult blood. Culture of the stool revealed a typical gram-negative rod which fermented glucose but not lactose, was nonmotile and did not produce H2S. The agent which MAY have caused this outbreak was:
- a) Escherichia coli
- b) Salmonella typhimurium
- c) Campylobacter jejuni
- d) Rota Virus
- e) Shigella sonnei
A 27-year-old IV drug user presents with difficulty swallowing. Examination of the oropharynx reveals white plaques along the tongue and the oral mucosa. Which of the following best describes the microscopic appearance of the microorganism responsible for this patient’s illness?
- a) Mold with septate hyphae
- b) Encapsulated yeast
- c) Budding yeast and pseudohyphae
- d) Mold with nonseptate hyphae
Two hours after a delicious Thanksgiving dinner of barley soup, roast turkey, stuffing, sweet potato, green beans, cranberry sauce, and pumpkin pie topped with whipped cream, the Smith family of four experience vomiting and diarrhea. Which one of the following organisms is MOST likely to cause these symptoms?
- a) Campylobacter jejuni
- b) Salmonella enteritidis
- c) Shigella flexneri
- d) Staphylococcus aureus
Following specialized transduction, if any of the bacterial genes transferred in are to be stabilized, what process must occur?
- a) Generalized transduction
- b) Conjugation
- c) Site-specific recombination
- d) Transformation
- e) Homologous recombination
Which genetic material is found in pathogenic Corynebacterium diphtheriae but not in nonpathogenic normal flora diphtheroids?
- a) Highly repetitive bacterial DNA
- b) A diphthamide on eEF-2
- c) An F factor
- d) An integrated temperate phage
- e) An episome
Which one of the following processes involves a sex pilus?
- a) Conjugation resulting in transfer of an R (resistance) factor
- b) Transduction of a chromosomal gene
- c) Integration of a temperate bacteriophage
- d) Transposition of a mobile genetic element
How is a prophage created?
- a) Through site-specific recombination of a temperate phage and bacterial DNA
- b) Through infection of a bacterial cell with lambda phage, lacking the lambda repressor
- c) Through activation of the recA gene product of an exogenote
- d) Through excision of bacterial DNA and active lytic replication of a bacteriophage
- e) Through infection of a bacterial cell with a virulent bacteriophage
Which of the following events is MOST likely to be due to bacterial conjugation?
- a) A gene encoding resistance to gentamicin in the Escherichia coli chromosome appears in the genome of a bacteriophage that has infected E. coli.
- b) An encapsulated strain of Streptococcus pneumoniae acquires the gene for capsule formation from an extract of DNA from another encapsulated strain.
- c) A strain of Pseudomonas aeruginosa produces ß-lactamase encoded by a plasmid similar to a plasmid of another gram-negative organism.
- d) A strain of Corynebacterium diphtheriae produces a toxin encoded by a prophage.
The process by which bacterial or plasmid DNA may be mistakenly incorporated (during assembly) into one phage being produced by the lytic life cycle and then that DNA-transferred to another bacterial cell which may acquire some new genetic traits is called
- a) Specialized transduction
- b) Conjugation
- c) Homologous recombination
- d) Generalized transduction
- e) Transformation
Which of the following mechanisms is most likely to be involved in multiple drug resistance transfer from one cell to another?
- a) Transformation of chromosomal genes
- b) Transposition
- c) Specialized transduction of a chromosomal gene for drug resistance
- d) Conjugation with a cell with a free plasmid carrying drug resistance
Conjugation with a cell with chromosomal drug resistance appears in the genome of a bacteriophage that has infected it.
- a) is the conversion of a virulent phage into a temperate phage.
- b) is a change in pathogenicity due to the presence of a prophage.
- c) is the immunity that a prophage confers on a bacterium.
- d) refers to the incorporation of a prophage into the chromosome.
- e) is the induction of a prophage to its virulent state.
Which of the following events is most likely due to bacterial transformation?
- a) A formerly non-toxigenic strain of Corynebacterium diphtheriae becomes toxigenic.
- b) A gene for gentamicin resistance from an Escherichia coli chromosome
- c) A strain of Neisseria gonorrhoeae starts producing a plasmid-encoded beta-lactamase similar to that another Gram-negative strain.
- d) A non-encapsulated strain of Streptococcus pneumoniae acquires a gene for capsule formation from the extract of an encapsulated strain.
Which of the following statements concerning recombinant DNA technology is false?
- a) Recombinant DNA technology provides a high degree of risk to the health of the general population.
- b) Thus far, no illnesses in laboratory workers have been traced to genetic recombinants.
- c) Recombinant DNA technology offers specific benefits to the scientific, medical, and general population.
- d) Mutant strains of bacteria produced by genetic recombination are often unable to survive in the natural environment.
- e) Production of large amounts of proteins such as insulin and human growth hormone has been made possible using recombinant DNA technology.
The ability of a cell to bind DNA to its surface and import it is required for which genetic process?
- a) Transformation
- b) Homologous recombination
- c) Conjugation
- d) Specialized transduction
- e) Generalized transduction
Hybridomas are formed by fusing antibody-producing white blood cells with:
- a) Bone marrow cells
- b) Viruses
- c) Red blood cells
- d) Bacteria
- e) Myeloma cells
Which type of genetic exchange in bacteria is susceptible to the activity of deoxyribonuclease?
- a) Transduction
- b) Transformation
- c) Transfection
- d) Conjugation
The form of genetic exchange in which donor DNA is introduced to the recipient by a bacterial virus is
- a) Transformation
- b) Horizontal transfer
- c) Transfection
- d) Conjugation
- e) Transduction
The formation of a mating pair during the process of conjugation in Escherichia coli requires
- a) Restriction endonuclease
- b) Transfer of both strands of DNA
- c) sex pilus
- d) Intergration of Transposon
- e) Lysis of the donor
The first vaccine for human use produced using recombinant DNA technology was the:
- a) AIDS vaccine
- b) Polio vaccine
- c) Hepatitis A vaccine
- d) Hepatitis B vaccine
- e) MMR vaccine
Answer Key Summary
Candidates may also benefit from studying specific laboratory science textbooks or taking online courses that cover the material tested in the MCQs. Additionally, practicing sample MCQs and reviewing the answers can help candidates identify areas where they may need to improve their knowledge or skills.
Overall, the MCQs for lab technologists are designed to be challenging and comprehensive, requiring candidates to demonstrate a high level of proficiency in the field of laboratory science.
