62 Questions
Eubacteria that lack cell walls and do not synthesize the precursors of peptidoglycan are called
Mycoplasmas
Most microorganisms pathogenic for humans grow best in the laboratory when cultures are incubated at
30-37°C
Which of the following specimens does not usually contain anaerobes?
Throat swab from a patient with a sore throat
How many organisms must be present in a clean catch midstream urine sample to be considered indicative of an infection?
> 10^5 CFU/mL
Which type of direct specimen involves collecting fluid from the lower respiratory tract?
Expectorated sputum
Which of the following represents a level of laboratory safety concerning biological hazards?
Level 1
Which method is not typically used to diagnose infections in the genital tract?
Cell culture using cycloheximide containing McCos cells
What is the primary use of charcoal in buffered charcoal yeast extract agar?
Act as a detoxifying agent
Which test is most readily used to confirm M. pneumoniae infection in the laboratory?
PCR
Which characteristic is essential in a nontreponemal serological test?
Measuring antibodies against lipids
For which purpose is enzyme immunoassay (EIA) performed on genital tract specimens?
Detecting bacterial antigens
What is a definitive method for identifying an anaerobic bacterium?
Cell wall fatty acid analysis using gas liquid chromatography
Which test differentiates M. catarrhalis from saprophytic neisseriae in respiratory samples?
Biochemical tests
Which test is useful for monitoring antibiotic treatment of primary or secondary syphilis?
Nontreponemal serological tests
The microorganism that could use CO2 as a carbon source and inorganic chemical compounds as an energy and electron source is:
Chemolithoautotroph
The compound that lacks the presence of phosphates in the structure of a bacterial Gram-positive cell wall is:
Tichuronic acid
The microorganism that has no ability to synthesize a growth factor is:
Auxoheterotrophic
The swarming of Proteus bacteria is inhibited if the concentration of agar is:
1.5%
Nitrosomonas is:
Chemolithoautotroph
Which one of the following is most responsible for the nature of the lesion on the foot caused by Staphylococcus aureus?
Superantigen toxin (StaphSAg)
The blood culture was negative. What is the best explanation for this?
This is typical in staphylococcal TSS. Only the StaphSAg needs to circulate
Which of the following is present in prokaryotes but not eukaryotes?
simultaneous transcription and translation
The nitrogen bases in DNA are bonded to the:
deoxyribose
Which of the following mediums is selective for Salmonella?
Hektoen Enteric Agar
Which hypersensitivity reaction is predominantly involving IgE?
Type I
Cytotoxic T cells kill their targets via which mechanisms?
Perforin and Granzyme B
Pattern recognition molecules can distinguish:
self from pathogen
Which of the following inhibits DNA gyrase?
Ciprofloxacin
Which of the following antimicrobial drugs is synthetic?
sulfanilamide
Which clinical situation would be appropriate for treatment with a narrow-spectrum antimicrobial drug?
treatment of strep throat caused by culture identified Streptococcus pyogenes
Which of the following is not a type of β-lactam antimicrobial?
glycopeptides
Which of the following resistance mechanisms describes the function of β-lactamase?
target mimicry
The etiology of the sore throat would have been best determined by:
Throat culture
Virulence means:
A term which presumes pathogenicity, but allows expression of degrees from low to extremely high
What laboratory test would be most likely to confirm the diagnosis of Lyme disease?
Borrelia burgdorferi immunoassay plus immunoblot
An F-pilus is essential for:
Plasmid transfer by conjugation
Which of the following statements about gene expression is false?
Translation begins at a site called a promoter
Which of the following is NOT characteristic of eukaryotic gene expression?
The mRNA is often polycistronic
The presence of which of the following is NOT typically used to determine the etiology of a sore throat?
DNA sequencing
Which diagnostic method is NOT typically associated with Lyme disease?
Throat culture
Which of these is a type of Anthrax?
Cutaneous Anthrax
On which of these media can Salmonella grow?
Desoxycholate agar
Salmonella can ferment which of the following?
Mannitol
Which of the following are antigens found in Enterobacteriaceae?
All of above
Which toxins are secreted by E. coli?
Heat stable toxin
Which antigens does Klebsiella have?
O antigen
Lactobacillus ferments sugars to produce which of the following?
Lactic acid
Which of the following antibiotics have an extended spectrum?
Aminoglycosides
What patterns of disease outbreaks in communities exist?
Sporadic Disease
What is the indicator used in the phenylalanine deamination test?
Ferric Chloride
How is antibacterial susceptibility determined?
Disk diffusion
Which phenotypic trait is associated with a systemic fungal pathogen?
Dimorphic shape
Which fungal pathogen causes Tinea corporis?
Trichophyton rubrum
How saturated with oxygen is the hemoglobin in blood leaving the lungs?
98-99%
Which type of bacterial enzyme does not need water for reactions?
Lyases
What is an important nutrient for bacterial teichoic acid?
PO4
Which bacterial group cannot grow at temperatures below 55°C?
Thermophiles
Which metabolic pathway is used by bacteria but not by eukaryotes?
Entner-Doudoroff
Which of the following are storage inclusions in bacteria?
Polyhydroxyalkonates
All of the following are true regarding penicillins EXCEPT
Penicillins don’t require dosage adjustment in renal failure.
Which of the following antibiotics does NOT inhibit nucleic acid synthesis?
Chloramphenicol
Which of the following antibiotics functions as a protein synthesis inhibitor?
Tetracycline
Study Notes
Microbiology Examination Questions
-
Competition Examination 2021-2022
- Questions 1-5: Multiple choice questions on various microbiology topics, including bacterial growth, metabolism, and identification.
Microbiology Topics
-
Serology
- Using complement fixation, cell culture, direct fluorescent antibody testing, nucleic acid amplification methods, and enzyme immunoassays to diagnose infections.
-
Lyme Disease
- Laboratory diagnosis of Lyme disease involves Borrelia burgdorferi immunoassay, immunoblot, and PCR of CSF.
-
Spore Formation
- Stages of spore formation: vegetative cell, sporulation, and germination.
-
F-pilus
- Essential for DNA transformation, chromosome transfer by conjugation, and plasmid transfer by conjugation.
-
Gene Expression
- More than one RNA polymerase can transcribe a specific gene at a given time; translation begins at a site called a promoter.
-
Eukaryotic Gene Expression
- Characteristics: 5' cap added to mRNA, poly A tail added to 3' end of mRNA, introns removed, and mRNA is often polycistronic.
Biology Exam
-
Multiple Choice
- Prokaryotes lack spliceosomes; DNA is bonded to deoxyribose.
-
Short Answer
- Compare conjugation, transformation, and transduction; differences between direct and indirect tests; selective mediums for Salmonella.
Additional Questions
-
Microbial Activity
- Determining microbial activity level involves measuring factors such as growth rate, metabolism, and enzyme activity.
-
Carbon Cycle
- Differences between carbon cycle in land and microorganisms: land-based carbon cycle involves decomposition, while microorganisms use carbon dioxide and release oxygen.
Q13-14
-
Antimicrobial Drugs
- Inhibit DNA gyrase, such as Ciprofloxacin; sulfanilamide is a synthetic antimicrobial drug; narrow-spectrum antimicrobial drugs for specific infections.
-
Antimicrobial Resistance
- Mechanisms: target mimicry, β-lactamase, and others.
Questions
-
Coagulase and Fibrinolysin
- Differences between coagulase and fibrinolysin in protection of pathogenic bacteria.
-
Media
- Purpose of using EMB, CLED, Deoxycholate citrate agar, Bismuth sulphate, and Thiosulfate-citrate-bile-sucrose (TCBS) media.
-
Cholera
- Pathogenesis of cholera diarrhea involves first complex compound, which is a toxin produced by Vibrio cholerae.
Choose the Suitable Answer
-
Types of Anthrax
- Cutaneous anthrax, pulmonary anthrax, and intestinal anthrax.
-
Salmonella
- Grows on Desoxycholate agar, Xylose-lysine desoxycholate agar, and Blood agar; ferments glucose and mannitol.
-
E. coli
- Secrete heat labile and heat stable toxins.
-
Lactobacillus
- Ferments sugars to produce lactic acid.
Answer All
-
Metabolic Pathways
- Regulation of metabolic pathways involves feedback inhibition, allosteric control, and substrate availability.
-
Extracellular Proteins
- Secreted from cytoplasmic membrane: lipopolysaccharides, capsules, and proteins.
Q4 - Fill the Blank
-
Aminoglycosides
- Have an extended spectrum, such as gentamicin.
-
Phenylanine Deamination
- Indicator used in phenylanine deamination test.
-
Antibacterial Susceptibility
- Determined through disc diffusion test.
-
Streptococcal Group
- Can hemolyze blood completely.
-
Polymyxin
- Used to treat gram-negative infections.
Example for Each
-
Fungal Pathogens
- Histoplasma capsulatum has a dimorphic shape; Trichophyton rubrum causes Tinea corporis; Candida albicans has adhesins as a virulence factor; Aspergillus fumigatus is a systemic fungus; fluconazole is an antifungal drug.
True or False
-
Hemoglobin
- True: Hemoglobin in blood leaving the lungs is about 98-99% saturated with oxygen.
-
Hemopoiesis
- True: Sites of hemopoiesis in infants occur in the yolk sac.
-
Aplastic Anemia
- True: Causes of aplastic anemia include toxic substances, such as pesticides, arsenic, and benzene.
-
Iron Storage
- True: Some iron is stored in the phagocytic as ferritin and hemosiderin.
-
Hypoxia
- True: Hypoxia occurs in patients when they ascend to high altitude.
This quiz assesses knowledge of biology topics, including microbial metabolism and cellular structure. Questions cover various aspects of biology, with equal weightage and 20 points each.
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