Select the best answer in the following questions:
1. L-form of bacteria are sensitive to:
a. Streptomycin
b. Amikacin
c. Tetracycline
d. Erythromycin
e. All of the above
2. Beta lactam antibiotics are:
a. Active against mycoplasma
b. Most active against organisms in the lag phase of growth
c. Bactericidal
d. Toxic to bone marrow
e. Mutagenic and thereby induce resistance to the drug
3. Imidazole:
a. Interfere with RNA and DNA synthesis
b. Inhibit protein synthesis at 50s ribosomal
c. Inhibit protein synthesis at 30s ribosomal subunit
d. Prevent formation of sterols of cytoplasmic membrane
e. Act by competitive inhibition of PABA
4. Choramphenicol:
a. Is an aminogycoside
b. Is bactericidal to typhoid bacillus
c. Binds to the 30s ribosome
d. Blocks protein synthesis in bacteria
e. Causes brownish discolonisation of teeth in young children
5. Which of these is a narrow spectrum antibacterial antibiotics:
a. Penicillin G
b. Tetracycline
c. Erythromycin
d. Ampicillin
e. Nystatin
6. In hypersensitivity to penicillin:
a. Erythromycin can be used as an alternative to treat Streptococcus pyogenes infections.
b. The antigen responsible is a degradation product of penicillin
c. Individual will be hypersensitive to ampicilln also
d. All are true
e. a+b are true
7. Meningococcal vaccine:
a. Is given to infants one week after birth
b. Contains attenuated group A and C meningococci
c. Consist of lipopolysaccharide andotoxin
d. Contains capsular polysaccharide
e. Is a toxic
8. In the laboratory diagnosis of gonococcal infection, all the following are requirements EXCEPT:
a. Endocervical swabs
b. Stuarts transport medium
c. Blood agar
d. Incubation in co2
e. Antibiotic containing chocolate agar
9. Virulence determinants of Neisseria gonorrheae:
a. Pili
b. IgA protease
c. Epithelial endocytosis
d. a + b
10. N.meningitidis can be differentiated from N.gonorrhoeae by:
a. Oxidase test
b. Catalase test
c. Fermentation of glucose
d. Fermentation of maltose
e. None of the above
11. Carriers are important source of infection in:
a. Meningococcal meningitis
b. Gonorrhea
c. Osteomyelitis
d. All of the above
e. a and b
12. Staphylococcal food poisoning is caused by:
a. Enterotoxin
b. Exfoliatin
c. Endotoxin
d. Haemolysin
e. Protein A
13. Staphylococcus aureus can cause all EXCEPT:
a. Nosocomial infection
b. Localized suppuration
c. Gas gangrene
d. Scalded skin syndrome
e. Bacteraemia
Single best answers:
1. endotoxic activity of gram negative bacteria is associated with :
a) Periplasmic gel
b) Flagellin protein in flagella
c) Lipid A
d) ‘O’ specific polysaccharide side chain
e) Teichoid acid
2. Which statement is not true regarding pili:
a) Rigid, surface appendages
b) Involve in bacteria adhesion
c) Are associated with clonisation in some species
d) Are organs of motility in some species
e) Are mainly protein
3. which statement(s) is/are applicable to both gram positive and gram negative bacterial cell walls?
a) Peptidoglycan comprises 50% of the cell wall
b) Teichoid acid is an important antigen
c) Phospholipids forms the outermembrane of the cell wall
d) Gram staining characteristics reside in the cell wall
e) All are true
4. in the technique called numerical taxonomy used in bacterial classification:
a) Some characteristics are given more weight than others in evaluation of non pathological and non morphological characters.
b) Equal weight is given to all characteristics examined and evaluated by computer to calculate a similarity profile
c) Genetic analysis of g+c content of DNA is measured
d) Sequence analysis of protein is done
e) Degree of bybridization of DNA is measured
5. in the exopotential (log) phase of growth curve:
a) Cell are very susceptible to antimicrobial agents
b) ⁰⁰Cell number increases four-fold every generation time
c) Conditions are ideal for spore formation
d) No metabolic activity can be measured
e) It is the first stage of the growth curve
6. a viable count is done by :
a) Estimation of total cell concentration
b) Measurement of mass density
c) Turbidometric measurements
d) Inoculation on solid media
e) All of the above
7. Psychrophiles :
a) Grow in the temperature range 30⁰C - 37⁰c
b) Are able to contaminate refrigerated food
c) Are able to use light energy
d) Prefer low pH
e) Require excess carbon dioxide for growth
8. energy is not expanded in the following mechanism(s) used by bacterial cell nutrient transport :
a) Passive diffusion from higher concentration to lower concentration
b) Facilitated diffusion with the aid permeases
c) Active transport of unaltered solutes utilizing carrier molecules
d) Group translocation of chemically altered solutes
e) a + b
9. in classification of microorganisms into nutritional types, bacteria that utilize organic compounds as the carbon and energy source are called:
a) photoautotrophs
b) photoheterotrphs
c) chemoautotrophs
d) chemoheterotrophs
e) auxotrophs
10. The cytoplasmic membarane bacteria:
a) protects the cytoplasm from toxic agents in the environment
b) it is a rigid membrane which gives shape to bacterial cell
c) it contains enzymes essential for production of energy
d) penicillin inhibits its formation
e) it is degraded by lysozyme
11. Factors that can determine the effectiveness of any antimicrobial procedure depend on all EXCEPT:
a) Mechanism of action of agent
b) Presence of pus.blood or stool
c) Type of microbe
d) Time of exposure
e) Size of container
12. The ideal chemotherapeutic agent should be:
a) selective toxicity to bacteria.not to host
b) effective in small dose
c) with reversed action (stopped by pus)
d) a and b
e) all of the above
13. Contaminated food can cause all EXCEPT:
a) food poisoning
b) parasitic infection
c) protozoa infection
d) meningitis
e) gastroenteritis
14. An organism can be virulent because:
a) it secretes potent exotoxin
b) it possesses endotoxin
c) it is highly invasive
d) a and b
e) all of the above
15. Man can resist microbial attack by:
a) red blood cells
b) histamine and serotonin
c) opsonin
d) a and b
e) all of the above
16. All of these have a role in the innate defense mechanism except :
a) Fluid element of the blood
b) Fever
c) Neutrophil
d) Lymphocytes
17. Immunity against diphteria depend on :
a) circulating anti-toxins
b) local IgA
c) cellular immunity
d) antibodies against organism itself
18. The most common disease produced by Listeria monocytogens is :
a) gastroenteritis
b) meningitis
c) intrauterine fetal death
d) enteric fever
e) pneumonia
19. Diphteria : all are true except :
a) diagnosis is mainly clinical , although it is bacterial disease
b) virulence tests are not important for diagnosis of carrier state
c) selective media is tellurite blood agar
d) vaccination does not prevent infection with corynebacterium diphteria
e) the toxin produce by the gravis and mitis types is the same
20. All these organisms share a common character EXCEPT :
a) Propionibacterium
b) Staphylococcus epidermidis
c) Branhamellea catarrhalis
d) Streptococcus pyogenes
e) Streptococci viridians
21. The capsule is a virulence factor for the following organisms EXCEPT :
a) Staphylococcus aureus
b) Streptococcus pneumonia
c) N.meningitidis
d) N.gonorrheae
22. Diagnosis of pneumococcal meningitis depends on the following :
a) Blood culture
b) CSF culture
c) Direct gram smear of CSF
d) Detection of pneumococcal antigen in CSF
e) All of above
23. Boiling is a method of :
a) sterilization
b) disinfection
c) degermination
d) cleaning
e) tyndillization
24. Which of these chemical disinfectants that can be used for sterilization :
a) gluteraldehyde 2 % for 20 minutes
b) gluteraldehyde 2 % for 10 hours
c) ethylene oxide gas
d) chlorohexidine
e) b + c
25. Which of these methods is not a method of sterilization :
a) refrigeration
b) ultrasonics
c) pasteurization of milk
d) boiling of instruments in water for 10 minutes
e) all of the above
26. of syringes in hot air oven?
a) 60º C – I hour
b) 100° C – 30 minutes
c) 121° C – 20 minutes
d) 160° C – 2 hours
e) 200° C – 20 minutes
27. Antimicrobial agents ( chemotherapy ) can be :
a) synthethic
b) naturally occuring
c) semisynthethic
d) all of the above
e) none of the above
28. prolonged use of broad spectrum antibiotics can lead to the :
a) vitamin B complex deficiency
b) Candidiasis in mouth and vagina
c) Infection with tuberculosisi
d) All are true
e) a + b only