Back exams Flashcards by Nezzie Teb

An antibacterial agent is considered static if it ___________________

An antibacterial agent is considered static if it doesn’t kill the bacteria, but stops their growth completely

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. Which of the following statements is true regarding the spores of Clostridium botulinum?

a. boiling water is cidal after about 9 hours
b. water at 1210 C is cidal after 5 minutes
c. water at 1160 C is cidal after 15 minutes
d. both a and b are correct
e. both a and c are correct

a. boiling water is cidal after about 9 hours

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According to the idea of exponential death phase, if we had a sample containing 30,000
bacteria, and we autoclaved it for 15 minutes, how many bacteria would be alive at the 4 minute
time?

300

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Which of the above characteristics apply to Free Flowing Steam ?
1. Sterilizes 2. Disinfects 3. Protein coagulation 4. Protein oxidation 5. Removes water necessary for enzymatic hydrolysis 6. Destroys only vegetative cells 7. Destroys spores

Free flowing steam:
2 disinfects
3 protein coagulation
6 destroys only vegetative cells

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Which of the above characteristics apply to hot air oven?
1. Sterilizes 2. Disinfects 3. Protein coagulation 4. Protein oxidation 5. Removes water necessary for enzymatic hydrolysis 6. Destroys only vegetative cells 7. Destroys spores

hot air oven:
1 sterilizes
3 protein coagulation
4 protein oxidation
5 removes water necessary for enzymatic hydrolysis
7 destroys spores

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What is the physical method for controlling bacteria is used prior to filtration in water purification?

sedimentation

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What is the physical method for destroying bacteria is used primarily in research labs for studying internal
components of bacterial cells?

sonic vibrations

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Which of the following pairs are mismatched?

a. syphilis - destroyed in minutes upon exposure to drying
b. tetanus spores - last indefinitely in dry conditions
c. gonorrhea- destroyed in an hour or so upon exposure to drying
d. Hepatitis B - destroyed quickly upon exposure to drying
e. HIV - destroyed quickly upon exposure to drying

d. Hepatitis B - destroyed quickly upon exposure to drying

Hepatitis B will last at least 7 days on a dry surface before being destroyed

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Some drugs such as antibiotics are stored in a dry condition for preservation. The mode of
action of bacterial control with this method is ___________

removal of water necessary for enzymatic hydrolysis

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Sunlight can be quite effective in killing bacteria. Mycobacterium can be killed in a few hours if
exposed. Currently it is thought that the mode of action of this process is ___________

protein oxidation

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Which of the following is NOT TRUE regarding the use of ultraviolet radiation for control of
bacterial growth?
a. it is nonionizing radiation
b. it has a low power of penetration
c. it will cause thymine to bond to another thymine resulting in a mutation
d. it is used for air disinfection in laminar flow hoods
e. the high intensity of light causes photo oxidation

e. the high intensity of light causes photo oxidation

The correct mode of action of UV light is DNA forms pyrimidine dimers which leads to mutation

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All of the following statements regarding cold temperatures are true EXCEPT

a. cold temperatures are not usually cidal to bacteria
b. refrigerator temperatures are primarily inhibitory to bacterial growth
c. freezer temperatures are primarily static to bacterial growth
d. the mode of action for freezing is removal of water for enzymatic hydrolysis
e. the mode of action of refrigeration is protein coagulation

e. the mode of action of refrigeration is protein coagulation

Refrigeration is inhibitory, it slows the rate of enzymatic reaction. This slows bacterial growth

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All of the following produce hyperactive ions EXCEPT:

a. gamma rays
b. x-rays
c. microwaves
d. cathode rays
e. both c and d are incorrect

c. microwaves

microwaves are too low energy to produce hyperactive ions

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Jams and jellies have 50 to 60% sugar concentrations. Therefore, the main reason most bacteria
do not grow in these foods is that their mode of action is _____________

plasmolysis of cells

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What is the difference between plasmolysis and plasmoptysis of cells?

Plasmolysis is when a cell shrinks due to water living.

Plasmoptysis is the bursting fourth of protoplasm from a cell, through rupture of the cell wall.

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for protein coagulation as a mode of action in chemical methods of control, True or false:
they disrupt the 3-D structure of proteins

true

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for protein coagulation as a mode of action in chemical methods of control, True or false:
they stop enzymatic metabolism

true

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for protein coagulation as a mode of action in chemical methods of control, True or false:
they are generally cidal

true

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for protein coagulation as a mode of action in chemical methods of control, True or false:
they are generally narrow spectrum

false

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for protein coagulation as a mode of action in chemical methods of control, True or false:
they cannot generally be used systemically

true

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True or false:

chlorhexidene is a phenol derivative

false

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True or false:

the mode of action of chlorhexidene is protein coagulation

true

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True or false:

chlorhexidene is used for hand scrubbing and preparing sites for surgery

true

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True or false:

chlorhexidene is safe since it is not absorbed into the deeper tissues of the skin

true

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regarding phenol and its derivatives, true or false: | they remain effective in the presence of organic matter

true

regarding phenol and its derivatives, true or false: | they have analgesic properties

true

regarding phenol and its derivatives, true or false: | they are broad spectrum

true

regarding phenol and its derivatives, true or false: | they are protoplasmic poisons

true

regarding phenol and its derivatives, true or false: | they are useful for systemic control of organisms

false

Halazone was used commonly by campers to disinfect water from streams until it was found to be ineffective against ____________.

protozoan cysts

The mode of action of halazone is considered to be _______________

protein oxidation

This agent is considered to be a mild oxidizing agent useful for disinfection of deep wounds

3% hydrogen peroxide

Many chemicals are said to be useful as "cold sterilants" but are really only disinfectants. Of the agents listed below, which one actually sterilizes? a. 3% hydrogen peroxide b. 70% ethanol c. 70% isopropanol d. betadine e. ethylene oxide

e. ethylene oxide

``` Which of the following statements are NOT TRUE concerning chemicals that disrupt lipoprotein membranes? a. they are surfactants b. they are generally cidal in action c. they are selectively toxic d. they can't be used systemically e. a, b and c are incorrect ```

c. they are selectively toxic since both humans and bacteria have lipoprotein membranes, chemicals which disrupt them are harmful to both us and bacteria making them non selective

This agent is a nonionic detergent that is used in mouthwashes to control bacteria a. sodium lauryl sulfate b. cetylpyridinium chloride c. benzalkonium chloride d. bile e. none of the above

e. none of the above

Taxo P discs are used in microbiology to help identify Streptococcus pneumoniae. They inhibit the growth of this organism because they contain this anionic detergent

bile

This cyclical peptide antibiotic is isolated from Bacillus species and is used in selective media such as Thayer Martin Selective agar

polymyxin E

This imidazole compound is a drug of choice that is used topically for dermatophytic infections such as athlete's foot

clotrimazole

This polyene antibiotic is isolated from Streptomyces species and is a main drug of choice for systemic mycoses

amphotericin B

This antibiotic is used for severe cases of tuberculosis

streptomycin

This antibiotic is effective against many Rickettsial diseases

tetracycline

This antibiotic was used for meningitis caused by Haemophilus influenzae but is now considered an alternate for that disease because of its toxicity

chloramphenicol

True or False? Halogens are effective antiseptics due to their mode of action, which is disruption of cell membranes

False

During which part of the growth phase are cells more susceptible to bacterial agents because the cells are sitting in their own toxic wastes

log death

True or False? Chemical agents such as chlorine may become inactivated in solutions due to adsorption on to large particles known as colloids suspended in the solution

true

Steam under pressure (15lbs/in2) is an effective means of sterilization since the pressure allows the temperature to reach _________ °C

121.5 °C

High vacuum sterilization is a much quicker method of sterilization simply because it uses a higher pressure allowing the temperature to reach __________ °C

135 °C

The batch method of pasteurization is currently set at 62.9 °C to kill Coxiella burnetii. Previously it was set a little lower to kill this pathogen (give genus and species)

mycobacterium bovis

This protein coagulant is an acid that is commonly used as a preservative in soft drinks and mouthwashes

benzoic acid

This heavy metal salt was commonly used in the eyes of newborns to prevent infections picked up as the baby passed through the birth canal

silver nitrate

This alcohol is used as a preservative in external preparations

benzyl

Dimorphic fungi can cause systemic mycoses. They are called dimorphic because they look like yeast in the body but look like molds when incubated at this temperature?

25 °C

True or False? Mouthwashes containing sodium lauryl sulfate should generally be expected to be more effective than those containing cetylpyridinium chloride

False

Give the mode of action and use for each of the following antibiotics: Dapsone Trimethoprim Neomycin

dapsone- antimetabloite. leprosy trimethroprim- antimetabloite. pneumocystis carinii pneumoniae neomycin- protein synthesis. topical creams

Give four major uses for the antibiotic erythromycin, giving the genus and species of each specific organism and the name of the disease

ophthalmic neonatorum. Neisseria gonorrhoeae. legionnaire's disease. Legionella pneumophila diphtheria. Corynebacterium diphtheriae pertusis. bordetella pertusis

Give two drugs for as antivirals including the specific uses of each of these drugs

acyclovir- herpes viruses | azidothymidine- AIDS (HIV)

Give the specific uses of each of the following drugs: Griseofulvin Flucytosine

griseofulvin- dermatophytes | flucytosine- systemic mycoses

Describe the Flash method of pasteurization of milk, giving the time and temperature needed

71.6 °C for 15 seconds

Explain how infra-red light can be used for disinfection. That is, what is its mode of action?

absorbed as heat. dehydration, protein oxidation, protein coagulation

Explain the mode of action of antimetabolites, using PABA (paraaminobenzoic acid) as an example, stating the specific substrate, antimetabolite, and product

sulfa drugs trimethoprim PABA (substrate)---x-------dihydrofolic acid----x--------tetrahydrofolic acid----purines, pyrimidines, amino acids

Define or describe these terms: bactericide MIC

bactericide-destroys bacteria except endospores | MIC- smallest concentration that visibly inhibits growth

Describe the use of the following agents: quinine metronidazole mebendazole

quinine- antimalarial metronidazole- amebic dysentery mebendazole- melminths

Explain, using a graph, the effectiveness of number of hand scrubs, using a nongermicidal soap, in a 15 minute period in reducing the load of bacteria on hands

number of bacteria decrease with each washing. Effective in reducing load each 15 minutes, but no residual action

``` Which of the following is/are a lactasmase resistant penicillin: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin ```

(I) oxacillin is a lactasmase resistant penicillin

``` Which of the following is/are a repository penicillin: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin ```

(H) benzathine penicillin is a repository penicillin

``` Which of the following is/are a natural penicillin resistant to acid in stomach: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin ```

(E) phenoxymethyl penicillin is a natural penicillin resistant to acid in stomach

``` Which of the following is/are a broad spectrum penicillin used for UTI's caused by pseudomonas aeruginosa: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin ```

``` Which of the following is/are a third generation cephalosporin: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin ```

(L) moxalactam is a third generation cephalosporin

``` Which of the following is/are a penicillin with an extra amino group effective against UTI's caused by Proteus mirabilis: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin ```

(G) ampicillin is a penicillin with an extra amino group effective against UTI's caused by Proteus mirabilis

``` Which of the following is/are used for MRSA: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin ```

(N) vancomycin is used for MRSA

``` Which of the following is/are a polypeptide antibiotic effective against G+ bacteria: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin ```

(M) bacitracin is a polypeptide antibiotic effective against G+ bacteria

``` Which of the following has protein coagulation as a mode of action and is used as an antiseptic and analgesic on mucous membranes : A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin ```

(A) cresyl acetate has protein coagulation as a mode of action and is used as an antiseptic and analgesic on mucous membranes

``` Which of the following is/are an organic form of mercury and a skin antiseptic: A. cresyl acetate B. benzyl penicillin C. carbenicillin D. amoxicillin E. phenoxymethyl penicillin F. thimerosal G. ampicillin H. benzathine penicillin I. oxacillin J. cephalothin K. cefotiam L. moxalactam M. bacitracin N. vancomycin ```

(F) thimerosal is an organic form of mercury and a skin antiseptic

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