1. Each of the following statements concerning the surface structures of bacteria
is correct EXCEPT:
A. Pili mediate the interaction of bacteria with mucosal epithelium
B. Polysaccharide capsules retard phagocytosis
C. Both gram-negative rods and cocci have lipopolysaccharide ("endotoxin") in their cell wall
D. Bacterial flagella are nonantigenic in humans because they closely resemble human flagella
in chemical composition
2. Each of the following statements concerning bacterial spores is correct EXCEPT:
A. Their survival ability is based on their enhanced metabolic activity
B. They are formed by gram-positive rods
C. They can be killed by being heated to 121 °C for 15 minutes
D. They contain much less water than bacterial cells
3. Each of the following statements regarding the selective action of antibiotics on bacteria is
correct EXCEPT:
A. Chloramphenicol affects the large subunit of the bacterial ribosome, which is different from
the large subunit of the human ribosome
B. Isoniazid affects the DNA polymerase of bacteria but not that of human cells
C. Sulfonamides affect folic acid synthesis in bacteria, a pathway that does not occur in
human cells
D. Penicillins affect bacteria rather than human cells because bacteria have a cell wall,
whereas human cells do not
4. Each of the following statements concerning the normal flora is correct EXCEPT:
A. The most common organism found on the skin is Staphylococcus epidermidis
B. Escherichia coli is a prominent member of the normal flora of the throat
C. The major site where Bacteroides fragilis is found is the colon
D. One of the most common sites where Sktphylococciis aureus is found is the nose
5. Each of the following statements concerning the resistance of bacteria to antimicrobial drugs
is correct EXCEPT:
A. Resistance to chloramphenicol is known to be due to an enzyme that acetylates the drug
B. Resistance to penicillin is known to be due to reduced affinity of transpeptidases
C. Resistance to penicillin is known to be due to cleavage by β-iactamase
D. Resistance to tetracycline is known to be due to an enzyme that hydrolyzes the ester linkage
6. Each of the following statements concerning the mechanism of action of antibacterial drugs
is correct EXCEPT:
A. Cephalosporins are bactericidal drugs that inhibit the transpeptidase reaction
and prevent cell wall synthesis
B. Tetracyclines are bacteriostatic drugs that inhibit protein synthesis by blocking tRNA binding
C. Aminoglycosides are bacteriostatic drugs that inhibit protein synthesis by activating
ribonuclease, which degrades mRNA
D. Erythromycin is a bacteriostatic drug that inhibits protein synthesis by blocking translocation of the polypeptide
7. Each of the following statements concerning the Gram stain is correct EXCEPT:
A. Escherichia coli stains pink because it has a thin peptidoglycan layer
B. Streptococcus pyogenes stains blue be cause it has a thick peptidoglycan layer
C. Mycobacterium tuberculosis stains blue because it has a thick lipid layer
D. Mycoplasma pncumoniae isn't visible in the Gram stain because it doesn't have a cell wall
8. In the Gram stain, the decolorization of cramnegative bacteria by alcohol is MOST closely related to
A. proteins encoded by F plasmids .
B. lipids in the cell wall
C. 70S ribosomcs
D. branched polysaccharicies in the capsule
9. Each of the following statements concerning resistance to antibiotics is correct EXCEPT:
A. Resistance to aminoglycosides can be due to phosphorylating enzymes encoded by R plasmids
B. Resistance to sulfonamides can be due to enzymes that hydrolyze the five-membered ring structure
C. istance to penicillins can be due to alterations in binding proteins in the cell membrane
D. Resistance to cephalosporins can be due to leavage of the β-lactam ring
10. Each of the following statements concerning penicillin is correct EXCEPT:
A. An intact (3-lactam ring of penicillin is required for its activity
B. The structure of penicillin resembled that of a dipeptide of alanine, which is a component of peptidoglycan
C. Penicillin is a bacteriostatic drug because autolytic enzymes are not activated
D. Penicillin inhibits transpcptiduses, which are required for cross-linking peptidoglycan
11. Each of the following statements concerning the killing of bacteria is correct EXCEPT:
A. A 70% solution of ethanol kills more effectively than absolute (100%) ethanol
B. An autoclave uses steam undef pressure to reach the killing temperature of 121 °C
C. The pasteurization of milk kills pathogens but allows many organisms and spores to survive
D. Iodine kills by causing the formation of thymine dimers in bacterial DNA
12. Each of the following statements concerning the normal flora is correct EXCEPT:
A. The normal flora of the colon consists predominantly of anaerobic bacteria
B. The presence of the normal flora prevents certain pathogens from colonizing the upper
respiratory tract
C. Fungi, eg, yeasts, are not members of the normal flora
D. Organisms of the normal flora are permanent residents of the body surfaces
13. Each of the following statements concerning the normal flora is correct EXCEPT:
A. Streptococcus mutans is found in the mouth and contributes to the formation of dental caries
B. The predominant organisms in the alveoli are viridans streptococci
C. Bacteroides fragilis is found in greater numbers than Escherichia coli in the colon
D. Candida albicans is part of the normal flora of both men and women
14. Each of the following statements concerning peptidoglycan is correct EXCEPT:
A. It has a backbone composed of alternating units of muramic acid and acetylglucosamine
B. Cross-links between the tetrapeptides involve D-alanine
C. It is thinner in gram-positive than in gramnegative cells
D. It can be degraded by lysozyme
15. Which one of the statements is the MOST accurate comparison of human, bacterial,
and fungal cells
A. Human cells undergo mitosis, whereas neither bacteria nor fungi do
B. Human and fungal cells have a similar cell all, in contrast to bacteria, whose cell
wall contains peptidoglycan
C. Human and bacterial cells have plasmids, hereas fungal cells do not
D. Human and fungal cells have similar ribosomes, whereas bacterial ribosomes are different
16. Each of the following events involves recombination of DNA EXCEPT:
A. transduction of a chromosomal gene
B. transposition of a mobile genetic element
C. integration of a temperate bacteriophage
D. conjugation, eg, transfer of an R (resistance) factor
17. Each of the following statements concerning the mechanism of action of antimicrobial drugs
is correct EXCEPT:
A. Vancomycin acts by inhibiting peptidoglycan synthesis
B. Quinolones, such as ciprofloxacin, act by inhibiting the DNA gyrase of bacteria
C. Erythromycin is a bactericidal drug that disrupts cell membranes by a detergentlike action
D. Aminoglycosides such as streptomycin are bactericidal drugs that inhibit protein synthesis
18. Which of the following events is MOST likely to.be due to bacterial conjugation?
A. A strain of Corynebacterium diphtheriae produces a toxin encoded by a prophage
B. A strain of Pseudomonas aeruginosa produces β-lactamase encoded by a piasmid
similar to a piasmid of another gram-negative organism
C. An encapsulated strain of Streptococcus pneumonia acquires the gene for capsule
formation from an extract of DNA from another encapsulated strain
D. A gene encoding resistance to gentamicin in the Escherichia coli chromosome
appears in the genome of a virulent bacteriophage that has. infected E coli
19. Each of the following statements concerning bacterial spores is correct EXCEPT:
A. Spores arc formed under adverse environmental conditions such as the absence of a
carbon source
B. Spores are resistant to boiling
C. Spores are metabolically inactive and contain dipicolinic acid, a calcium chelator
D. Spores are formed primarily by organisms of the genus Neisseria
20. Each of the following is a typical property of obligate anaerobes EXCEPT:
A. They generate energy by using the cytochrorne svstem
B. They grow best in the absence of air
C. They lack superoxide dismutase
D. They lack catalase
21. Each of the following statements concerning the killing of bacteria is correct EXCEPT:
A. Lysozyme in tears can hydrolyze bacterial cell walls
B. Silver nitrate can inactivate bacterial enzymes
C. Detergents can disrupt bacterial eel I membranes
D. Ultraviolet light can degrade bacterial capsules
22. Chemical modification of benzylpenicillin (penicillin G) has resulted in several beneficial
changes in the clinical use of this drug. Which one of the following is NOT one of those
beneficial changes?
A. Lowered frequency of anaphylaxis
B. Increased activity against gram-negative rods
C. Increased resistance to stomach acid
D. Reduced cleavage by penicillinase
23. Each of the following statements concerning bacterial and human cells is correct EXCEPT:
A. Bacteria are prokaryotic (ie, they have one molecule of DNA, are haploid, and have
no nuclear membrane), whereas human cells are eukaryotic (ie, they have multiple
chromosomes, are diploid, and have a nuclear membrane)
B. Bacteria derive their energy by oxidative phosphorylation within mitochondria in a
manner similar to human cells
C. Bacterial and human ribosomes are of different sizes and chemical compositions
D. Bacterial cells possess peptidoglycan, whereas human cells do not
24. Each of the following statements concerning the mechanisms of resistance to antimicrobial
drugs is correct EXCEPT:
A. R factors are plasmids that carry the genes for enzymes which modify one or more drugs
B. Resistance to some drugs is due to a chromosomal mutation that alters the receptor
for the drug
C. Resistance to some drugs is due to transposon genes that code for enzymes which in
activate the drugs
D. Resistance genes are rarely transferred by conjugation
25. Each of the following statements concerning penicillin is correct EXCEPT
A. The drug is bacteriostatic
B. The drug inhibits cell wall synthesis
C. The drug is made by a fungus
D. The drug may destroy bacteria by activating their own autolysins
26. Each of the following statements concerning the structure and chemical composition of
bacteria is correct EXCEPT:
A. Some gram-positive cocci contain a layer of teichoic acid external to the peptidoglycan
B. Some gram-positive rods contain dipicolinic acid in their spores
C. Some gram-negative rods contain lipid A in their cell wall
D. Some mycoplasmas contain pentaglycine in their peptidoglycan
27. What is disbacteriosis?
A. Reduction of quantity of the anaerobic bacteria of the colon.
B. Infringements of balance between microbes of the small intestine and the colon.
- Quantitative and qualitative infringements of balance between microbic populations in structure of microflora
D. Increases of quantityof pathogenic microorganisms at surfaces of a skin
E. Condition of microflora of the experimental animal, caused by intervention of the experimenter
28. Choose drugs which are used for treatment dysbacteriosis:
A. Penicillinum, Cephalosporinum
B. Antimicrobic serums and immunoglobulines
C. Vitamins and hormones
D. Lysozym and interferon
E. Colibacterin, bifidobacterin
29. For the first - second degrees of cleanliness of vaginal secret typically:
A. The alkaline pH, is not enough glicogen and glucose
B. The pH is 4.7, presence of lactic acid bacilli
C. The alkalescent pH, leukocytes, staphylococci
D. The alkaline pH, staphylo-and streptococci, leukocytes
E. The alkaline pH, presence of proteins, single cocci
30. Anaerobic conditions can be created with the help:
A. Zoessler's method
B. Shukevich's method
C. Veinberg's method
D. Fortnes' method
E. Paster' method
31. Choose the nutrients media on which it is possible to grow anaerobic microorganisms:
A. Endo's and Lewin's media
B. Meat - pepton agar, meat - pepton broth
C. Sugar - blood agar Zoessler, Kitt-Tarozzi's medium
D. The curtailed serum, meat- pepton gelatin
E. Blood agar, serum agar
32. At definition peptolytic properties determine allocation in the nutrient medium:
A. Carbonic acids and waters
B. Glucose and lactoses
C. Carbonic acids and nitrogen
D. Mannitol and metanol
E. Indol and hydrogen sulphide
33. At allocation of pure culture of anaerobic microorganisms the received isolated colony sow on:
A. Kitt-Tarozzi's medium
B. Hiss media
C. Zoessler's medium
D. Endo's medium
E. Ploskirev medium
34. The third stage of allocation of pure culture of aerobic microorganisms will be:
A. Inoculating of a mix (material) on a solid nutrient medium
B. Biochemical and serological identification
C. Microscopic examination of a material
D. Check of cleanliness of the allocated culture and its identification
E. Studying of isolated colonies and Inoculating on the slant agar
35. Resistance of bacteria to acid depends from present in cytoplasm
А. lipopolysaccharides
В. oxyacid, fatty acid
С. acetylglucosamine
D. diaminopimelic acid
Е. poliphosphates
36. Cell wall of gram-positive bacteria consist of:
А. thin monolayer peptidiglycan
В. lipoproteins
С. polilayer peptidiglican
D. lipopolysaccharides
Е. outer membrane
37. Which with these substances can damage bacteria cell wall :
А. sulphonamides
В. lysozyme
С. interferone
D. alcohol
Е. streptomycin
38. After what sign of mycoplasma differ from bacteria :
А. by structure of the nucleosis
В. by absence of cell wall
С.by intracellular parasite
D. by tinctorial properties
Е. by structure of cytoplasmatic membrane
39. Which concentration of ethyl alcohol would is the most effective disinfectant?
A. 100% D. 50%
B. 70% E. 30%
C. 60%
40. Gnotobiology is a science which studies:
A. Microflora of the person
B. Microflora of experimental animals
C. Life of the microbe-free animals
D. Microflora of different parts of an organism
E. Influence of various factors on normal microflora
41. Choose among given microorganisms which occupy a skin:
A. Bacteroides, Vibrio, Spirillum
B. Bacillus subtilis, Streptococcus pneumoniae, Pseudomonades
C. Clostridium, Staphylococcus aureus, Micrococcus roseus,
D. Staphylococcus, Propionobacterium, Peptococcus
E. Escherichia coli, Clostridium perfringens, Neisseria
42. Choose among the listed drugs eubiotycs:
A. Bacteriocines
B. Antibiotics
C. Bificol
D. Lysozim
E. interferon
43. Choose among the microorganisms of a colon given the basic kinds:
A. Bacteroides, Bifidobacterium, Lactobacillus
B. Staphylococci, streptococci, Proteus
C. Clostridium, peptococci, esherichia
D. Candida, spirochetes, micrococci