Micro Exam 3
Select the INCORRECT combination: A. Alcohol/Excellent activity against all groups of organisms including spores B. Chlorhexidine/kills organism at much slower rate than alcohol C. Iodophors/more toxic than alcohol D. Triclosan/deodorant soap and tooth paste E. Iodine/microbicidal against virtually all organisms including spore-forming bacteria and mycobacteria
A. Alcohol/Excellent activity against all groups of organisms including spores
Which of the following simultaneously contains both DNA and RNA? A. Bacteria B. Viruses C. Plasmids D. Prions
A. Bacteria
What important enzyme(s) is (are) found in the periplasmic space of Gram-negative bacteria? A. Beta-lactamase B. Catalase C. Superoxide dismutase D. All of the above
A. Beta-lactamase
Cytoplasmic membrane of most prokaryotes do NOT: A. Contain Sterols B. Have a lipid bilayer C. Assist in respiration D. Contain transport proteins
A. Contain Sterols
The following are true of gram positive bacteria membrane characteristics EXCEPT A. Gram positive bacteria have thinner cell walls compared to gram negative bacteria B. Gram positive bacteria are more susceptible to antibacterial activity of penicillin compared to gram negative bacteria C. Gram positive bacteria are more sensitive to Lysozyme compared to gram negative bacteria D. Some strains of gram negative bacteria exhibit sporulation E. Gram positive bacteria do not possess cell outer membrane
A. Gram positive bacteria have thinner cell walls compared to gram negative bacteria
Which of the following are components of gram negative outer membrane? A. Lipopolysaccharide, Phospholipids and Proteins B. Teichoic acid, Lipoteichoic acid and Proteins C. Cytoplasmic membrane, Peptidoglycan, Phospholipids D. Cell wall synthetic proteins, Phospholipids and Proteins E. Chromosome, Ribosome, Capsul
A. Lipopolysaccharide, Phospholipids and Proteins
Which of the following is an example of intracellular pathogen? A. Mycobacterium spp. B. Staphylococcus C. Streptococcus D. Both A and C are correct
A. Mycobacterium spp.
Tetanus toxin inhibits the release of A. Neurotransmitters (glycine and GABA) B. Acetylcholine C. Cytoxin C D. Calcium blockers
A. Neurotransmitters (glycine and GABA)
What is a risk factor for the development of diphtheria? A. Non-immune patient traveling to India for the summer B. A patient that is eating contaminated food C. A patient with large wounds who has been seriously injured in a car accident D. A &B
A. Non-immune patient traveling to India for the summer
The lack of nuclear membrane-------- A. Simplifies the requirements for protein synthesis B. Complicates the control mechanisms of protein synthesis C. Transcription and translation are not coupled D. All of the above
A. Simplifies the requirements for protein synthesis
If WBCs are present, in a gram staining slide they should appear completely: A. gram negative B. gram positive C. transparent D. all of the above
A. gram negative
Major targets for antibacterial drugs are---- ribosomes. A. 80S B. 70S C. Both A and B are correct
B. 70S
Sedimentation coefficient of ribosomes of bacteria is: A. 80S (60S+40S) B. 70S (50S+30S) C. 70S (40S+30S) D. 80S (40S+40S)
B. 70S (50S+30S)
Obligate anaerobes? A. Grow in the presence of oxygen B. Cannot grow in the presence of oxygen C. Can grow with or without the presence of oxygen D. Grows in the presence of oxygen and humidity only
B. Cannot grow in the presence of oxygen
The Gram stain and acid-fast stain are based on properties of thE A. Outer membrane B. Cell wall C. Nucleus D. Cytoplasm
B. Cell wall
Cell wall is present for-----, and ------ but absent in --------. A. Bacteria, eukaryote, fungi B. Fungi, bacteria, eukaryote C. Eukaryote, fungi, bacteria
B. Fungi, bacteria, eukaryote
Periplasmic space is present in: A. Gram positive bacteria B. Gram negative bacteria C. Acid fast bacteria D. Both A and B
B. Gram negative bacteria
The use of penicillin prevents peptidoglycan synthesis, it is more effective on A. gram negative B. Gram positive C. Cell fusion D. Gram negative outer membrane
B. Gram positive
Which of the following has thick peptidoglycan layer? A. Gram negative B. Gram positive C. Both
B. Gram positive
Endotoxin is produced by ----- and exotoxin is produced by------ A. Gram positive, gram negative B. Gram-negative, gram-positive and gram-negative C. Gram-positive and Gram-negative, gram-negative
B. Gram-negative, gram-positive and gram-negative
Which of the following methods is used for endoscopes and surgical instruments with plastic components? A. Autoclave B. High-level disinfectants C. Quaternary ammonium compounds D. All of the above
B. High-level disinfectants
Microbial population of the vagina is more diverse and influenced by what? A. Stress B. Hormones C. Environmental factor D. A &B E. All of the above
B. Hormones
All of the following statements about capsule is false EXCEPT A. It is made up of lipids and polypeptide B. It gives the bacteria property of being antiphagocytic C. Protection of colony from environment, antimicrobials, and host response D. Strengthens cell wall E. Give the cell shape and structure
B. It gives the bacteria property of being antiphagocytic
Which of the following is TRUE about LPS found in gram positive or gram negative bacterial cell wall? A. LPS is an endotoxin that consist of three structural sections Lipid A or B, Core Polysaccharide and O- antigen B. Lipid A is essential for bacterial viability and is responsible for endotoxin activity C. Core polysaccharide is a branch of 50 to 100 repeating saccharide units of 4 to 7 sugars per unit D. O- antigen is made up of branched polysaccharide of 9 to 12 sugars E. Lipid B is distinguishes serotypes of bacterial species
B. Lipid A is essential for bacterial viability and is responsible for endotoxin activity
What phase is growth the fastest? A. Log and lag B. Log C. Lag D. All of the above
B. Log
Which bacteria forms adhesion as virulence factor? A. E. coli B. Neisseria C. Staph D. Strep E. Both A and B
B. Neisseria
Which of the following is ESSENTIAL for the structure, replication and survival of gram-positive bacteria? A. Capsule B. Peptidoglycan C. Teichoic acid D. Lipoteichoic acid E. Flagellum
B. Peptidoglycan
Penetration of beta lactam antibiotics requires A. Thick peptidoglycan layer B. Pores in the outer membrane C. Cytoplasmic membrane
B. Pores in the outer membrane
Gram stain----------, culture--------- specimens may be the result of contamination of reagents and other supplies, presence of antimicrobial agents, or failure of organisms to grow under usual culture conditions (media, atmosphere, etc.). A. Negative, positive B. Positive, negative C. Negative, negative
B. Positive, negative
At the end of gram staining procedure, Gram positive bacteria will be: A. Red B. Purple C. Green D. Both A and B are correct
B. Purple
When placed into a hypertonic solution, a bacterial cell will: A. Lyse B. Shrink C. Swell D. Not be affected
B. Shrink
Which of the following is NOT a strict pathogen? A. Mycobacterium tuberculosis B. Staphylococcus aureus C. Neisseria gonorrhoeae D. Fransicella tularensis E. Plasmodium spp
B. Staphylococcus aureus
Why can obligate intracellular organisms survive only in host cells? A. They can produce their own ATP B. They utilize ATP from host's T-cell C. They have their own mitochondria D. A and C
B. They utilize ATP from host's T-cell
Gram-positive bacteria has ----, and gram negative has ---- peptidogylcan. A. Thin, thick B. Thick, thin C. Thick, thick D. Thin, thin
B. Thick, thin
Select the correct combination: A. Staphylococcus/bacillus B. Treponeme/spirillum C. E.coli/coccus D. Nocardia/rod
B. Treponeme/spirillum
Intermediate-level disinfectants are used to clean surfaces or instruments in which contamination with bacterial spores is: A. Likely B. Unlikely
B. Unlikely
If a patient is suspected to have C. difficile, anyone in contact with that patient should perform what preventative method? A. Use hand sanitizer every time they come in contact with infected patient. B. Wash hands with soap and water C. No preventative efforts should be taken D. C. difficile is self-limiting and non-infectious
B. Wash hands with soap and water
For slide libraries and teaching collections that will be stored for longer periods, immersion oil can be removed with ----------solution and the slides can be cover-slipped using ---------to prevent fading. A. Alcohol, wax B. Xylene, permount C. Formaldehyde, permount D. Alcohol, crystal violet
B. Xylene, permount
Select the INCORRECT statement about Penicillin-binding proteins (PBPs) : A. Are present in gram-negative bacteria B. Are present in periplasmic space C. Are a part of outer membrane of cell wall D. Also called transpeptidases E. Are target of beta-lactam antibiotics
C. Are a part of outer membrane of cell wall
Select the INCORRECT statement about quaternary ammonium compounds: A. Act by denaturing cell membranes to release the intracellular components B. Bacteriostatic at low concentrations and bactericidal at high C. Are bactericidal for Pseudomonas strains D. Mycobacteria are resistant to them E. Fungus Trichophyton is resistant
C. Are bactericidal for Pseudomonas strains
Used to prevent unwanted microorganism from contaminating the specimen A. Intubation B. Needle aspiration C. Aseptic technique D. Isolation technique
C. Aseptic technique
The bacterial chromosome consists of subunits: A. 30S B. 50S C. Both 30S and 50S D. 80S
C. Both 30S and 50S
Capsule is present in: A. Gram positive B. Gram negative C. Both A and B D. None of the above
C. Both A and B
Which of the following is NOT an opportunistic pathogen? A. S. aureus B. E. coli C. C. difficile D. C. albicans
C. C. difficile
Bacterial cell walls are made up of all of the following EXCEPT: A. Peptidoglycan B. Teichoic acid C. Cholesterol D. Lipoprotein E. LPS
C. Cholesterol
Select the INCORRECT statement about bacteria: A. Single, circular haploid DNA B. No nuclear membrane C. Cytoplasmic membrane contains sterol D. 0.5-3.0um size
C. Cytoplasmic membrane contains sterol
Respiration takes place via----- in prokaryotes and ----- in eukaryotes. A. Mitochondria, cytoplasmic membrane B. Cytoplasmic membrane, mitochondria C. Endoplasmic reticulum, mitochondria D. Mitochondria, lungs
C. Endoplasmic reticulum, mitochondria
Which of the following is a heat-stable, lipopolysaccharide component of the outer membrane of gram-negative bacteria? A. Exotoxin B. Enterotoxin C. Endotoxin D. None of the above
C. Endotoxin
Select the correct statement about plasmids: A. Small, circular B. Extra-chromosomal DNA C. Essential for survival of bacteria D. May confer antibiotic resistance
C. Essential for survival of bacteria
All of the following are true regarding C. difficile EXCEPT: A. It is part of normal flora B. Forms toxin A which attracts neutrophils and stimulates release of cytokines. C. Forms toxin B which decreases permeability of intestinal wall. D. Able to form spores
C. Forms toxin B which decreases permeability of intestinal wall.
All of the following pairings are false EXCEPT? A. Gram positive/ Thin Peptidoglycan layer B. Gram negative/ Thick Peptidoglycan layer C. Gram positive/ Teichoic acid D. Gram positive/ Periplasmic space E. Gram negative/ Lipoteichoic acid
C. Gram positive/ Teichoic acid
Facultative anaerobes? A. Grow in the presence of oxygen B. Cannot grow in the presence of oxygen C. Grow with or without the presence of oxygen D. Grows only in the presence of oxygen and humidity
C. Grow with or without the presence of oxygen
Which of the following Diphtheria toxin is responsible for cardiac and neurological dysfunction due to protein synthesis inhibition? A. A-subunit exotoxin B. B-subunit exotoxin C. Heparin-binding epidermal growth factor D. A &B
C. Heparin-binding epidermal growth factor
Staining characteristics may be influences by a number of variables EXCEPT: A. Culture age B. Media C. Incubation pH and temperature D. Staining methods E. The presence of inhibitory substances
C. Incubation pH and temperature
What are the four phases of bacterial growth in order of occurrence? A. Death, stationary, lag, log B. Stationary, log, lag, death C. Lag, log, stationary, death D. Log, lag, stationary, death
C. Lag, log, stationary, death
Which of the following bacteria DOES NOT use arthropod bite for entry? A. Yersinia pestis B. Fransicella C. Listeria D. Rickettsia E. Both A and D are correct
C. Listeria
Antibacterial activity of Penicillin: A. Gram positive are more resistant B. Gram negative are more susceptible C. None of the above
C. None of the above
Exotoxins are considered? A. Peptidoglycans B. Endotoxins C. Proteins D. Polysaccharide-O E. LPS
C. Proteins
Which bacteria forms biofilm? A. Staph B. Strep C. Pseudomonas D. All
C. Pseudomonas
Following are the functions of normal commensal population of microbes EXCEPT: A. Stimulate the immune response B. Protect against highly virulent microorganisms C. Secrete defensins D. Provide essential growth factors E. Participate in the metabolism of food products
C. Secrete defensins
Select the INCORRECT combination: A. C. tetani/inhibitory transmitter release blocked B. C. botulinum/excitatory transmitter is blocked C. V. cholera/decreased adenylate cyclase activity D. C. diphtheria/inactivates elongation factor-2
C. V. cholera/decreased adenylate cyclase activity
Pilli and flagella are made out of A. Carbohydrate B. lipids C. protein D. nucleic acid
C. protein
Average size of prokaryote is: A. 5 um B. >5um C. <3 um D. 2-5 um
D. 2-5 um
All of the following are functions of the capsule except? A. Aids in attaching to host surfaces B. Protection from phagocytosis C. Provides nourishment D. A and B E. A, B, and C
D. A and B
The requirements for growth are? A. Carbon and nitrogen and water B. An energy source and various ions C. Hot and humid weather D. A and B E. A, B, and C
D. A and B
Which of the following tissues is commonly involved in viral shedding? A. Skin B. GI tract C. Brain D. A and B E. All of the above
D. A and B
Bacterial capsule is------ A. Poorly antigenic B. Antiphagocytic C. Major virulence factor D. All of the above
D. All of the above
Gram negative bacteria has: A. Thinner cell wall B. LPS C. Endotoxin D. All of the above
D. All of the above
Periplasmic space of bacteria contains enzymes involved in the following: A. Transport B. Degradation C. Synthesis D. All of the above
D. All of the above
Which of the following contains nucleic acids? A. Virus B. Bacterium C. Fungus D. All of the above
D. All of the above
Which of the following is/are ABSENT in prokaryotes? A. Mitochondria B. Golgi bodies C. Endoplasmic reticulum D. All of the above
D. All of the above
What type of DNA is found in bacteria? A. Chromosomal DNA B. Plasmid DNA C. Diploid DNA D. Both A and B are correct
D. Both A and B are correct
LPS is made up of: A. Lipid A B. Core polypeptide C. O antigen D. Both A and C
D. Both A and C
Which of the following is NOT a component of the bacterial envelope? A. Capsule B. Cell wall C. Cell membrane D. Capsid
D. Capsid
The most common organism colonizing the outer ear is: A. Haemophilus spp B. Neisseria spp C. S. viridians D. Coagulase-negative staphylococcus E. Klebsiella
D. Coagulase-negative staphylococcus
What does prokaryote have? A. Nucleus B. Mitochondria C. Endoplasmic reticulum D. DNA E. All of the above
D. DNA
What additional procedures in conjunction with other clinical and laboratory findings are NOT required to confirm findings suggested by Gram-stained smears? A. Special stains B. Direct antigen tests C. Inclusion of selective media D. Electron microscopy
D. Electron microscopy
Proper smear preparation should produce -------- of organisms sufficiently dense for easy visualization but -------enough to reveal characteristic morphological characteristics. A. Multilayer, thick B. Monolayer, thick C. Multilayer, thin D. Monolayer, thin
D. Monolayer, thin
Which of the following stops the growth of Gram negative bacteria A. MacConkey Agar B. Blood agar C. Methylene blue agar D. None of the above
D. None of the above
Additional staining procedures are recommended for -------------clinical specimens in which no organisms are observed by the Gram stain method. A. Urine B. Blood C. CSF D. Purulent E. Non purulent
D. Purulent
All bacteria are potentially susceptible to penicillin G EXCEPT: A. Gram positives B. Neisseria, spirochetes C. Most anerobes D. S. aureus
D. S. aureus
What are plasmids? A. Circular RNA B. Circular DNAs C. Smaller, circular DNAs D. Smaller, circular, extrachromosomal DNAs
D. Smaller, circular, extrachromosomal DNAs
Give an example of encapsulated microorganism? A. Brucella B. Fransicella C. Listeria monocytogenes D. Streptococcus pneumonia
D. Streptococcus pneumonia
Bacterial virulence mechanisms include all of the following EXCEPT: A. Adherence B. Toxins C. Endotoxins D. Susceptibility to antibiotics E. Intracellular growth
D. Susceptibility to antibiotics
Which of the following components is present in Gram-positive bacteria but NOT in Gram negative bacteria? A. Peptidoglycan B. Capsule C. Flagella D. Teichoic acid
D. Teichoic acid
Acid-fast staining is used when bacteria contain? A. Sex pili B. Chemotaxis C. Slime layer D. Wax-like lipid coat
D. Wax-like lipid coat
Name the major types of toxins that exist A. LPS B. Enterotoxins C. Exotoxins D. LTS E. A, B, C
E. A, B, C
Bacteria can become resistant to beta lactam antibiotics by: A. Prevention of the interaction between the antibiotic and the target PBP B. Hydrolysis of beta-lactamases C. Acquisition of new PBP D. Both A and B are correct E. All of the above
E. All of the above
Basic mechanisms of antibiotic action include: A. Blockage of cell wall synthesis B. Blockage of protein synthesis (Both 30S and 50S) C. Blockage of DNA replication and RNA synthesis D. Both A and B are correct E. All of the above
E. All of the above
Smears for Gram stain may be prepared from: A. Clinical specimens B. Broth cultures C. Colonies growing on solid media D. Both A and B are correct E. All of the above
E. All of the above
What is (are) the symptom(s) of respiratory diphtheria? A. Pharyngitis B. Sore throat C. Low-grade fever D. A &C E. All of the above
E. All of the above
Select the INCORRECT combination about vaginal flora: A. N. gonorrhoeae/common cause of vaginitis B. Newborn girls for 6 wks/lactobacilli C. Prepuberty/staphylococci, streptococci, enterobacteriaceae D. Puberty/lactobacilli, streptococci,enterococcus,mycoplasma, ureaplasma E. All of the above are correct
E. All of the above are correct
What are the functions of a bacterial capsule? A. Serves to protect bacteria from phagocytosis B. Aids bacteria in attaching to host surfaces C. Are virulence factors D. A and B are correct E. All of the above are correct
E. All of the above are correct
Which of the following statements is true about a bacterial cell membrane? A. It is exceptionally rich in proteins (up to 70% of its weight) B. It does not contain sterol except mycoplasma C. The bacterial chromosome is attached to it D. Both A and B are correct E. All of the above.
E. All of the above.
The methods of controlling bacterial growth A. Steam autoclave B. Formaldehyde C. Filtration D. Ultraviolet E. All the above
E. All the above
Interpretation of Gram-stained smears involves consideration of all of the following EXCEPT: A. Staining characteristics B. Cell size C. Shape D. Arrangement E. Appearance of colonies
E. Appearance of colonies
Which of the following bacteria has fungi-like appearance? A. Staphylococcus B. E. coli C. Actinomyces D. Nocardia E. Both C and D
E. Both C and D
All of the following pairings are correct EXCEPT? A. Biofilm/ Protection of colony from environment B. Flagellum/ Movement and Chemotaxis C. Pili/ Adherence D. Teichoic acid/ Activator of innate host protections E. Capsule/ Permeation of small hydrophilic molecules
E. Capsule/ Permeation of small hydrophilic molecules
Sterilization is total destruction of all microbes except: A. Bacterial spores B. Mycobacteria C. Nonenveloped viruses D. Fungi E. None of the above
E. None of the above
Select the INCORRECT statement: A. Retain the primary dye (gram-positive) B. Take the color of the counterstain (gram-negative) C. The primary dye is crystal violet D. The secondary dye is usually either safranin O or basic fuchsin. E. The secondary dye is always safranin
E. The secondary dye is always safranin
