Physical and Chemical Agents

Q1: Ethylene oxide is used to destroy or kill which of the following microbes?

A Bacteria

B Spores

C Fungi

D All of these

Q2: Which of the following is/are vapour-phase disinfectant/s?

A Formaldehyde

B Ethylene oxide

C Both (a) and (b)

D None of these

ANS:C - Both (a) and (b)

No answer description is available.

Q3: Which of the following articles can be sterilized in an autoclave?

A Gloves

B Culture media

C Dressing material

D All of these

ANS:D - All of these

Yes, it is possible to sterilize gloves.

Q4: Which of the following does not kill endospores?

A Autoclave

B Incineration

C Hot air sterilization

D Pasteurization

ANS:D - Pasteurization

I think A because autoclave use steam under pressure high temperature and high pressure that can kill endospores but pasteurisation eliminate pathogenic organisms HTST can't kill endospores.

Q5: If a canning procedure is not properly followed, which type of microbe is most likely to grow in the canned food?

A Obligate Aerobe

B Acidophile

C Mesophile

D Obligate Anaerobe

ANS:D - Obligate Anaerobe

No answer description is available.

Q6: Which of the following is bactericidal?

A Membrane filtration

B Ionizing radiation

C Freeze-drying

D Deep freezing

ANS:B - Ionizing radiation

No answer description is available.

Q7: Ethylene oxide is used to destroy or kill which of the following microbes?

A Bacteria

B Spores

C Fungi

D All of these

Q8: Which disinfectant would be most effective against Staphylococcus found in a blood spill?

A Phenol

B Cetylpyridinium chloride

C Hexachlorophene

D None of these

ANS:D - None of these

Please explain the answer.

Q9: If a 1:600 dilution of a test compound kills a standard population of Staphylococcus aureus in 10 minutes but not 5 minutes while a 1:60 dilution of phenol kills the population in the same time, what is the phenol coefficient of the test compound?

A 1

B 5

C 10

D 50

ANS:C - 10

Ist dilution factor /second final dilution factor.

=> 1/600/1/60 = 600/60 = 10.
So, the answer is 10.

Q10: Which of the following was the first widely used antiseptic and disinfectant?

A Chlorine

B Phenol

C Iodine

D Alcohol

ANS:B - Phenol

How will use to phenol?

Q11: Which of the following material is sterilized by heating at 160°C in a hot air oven for one hour?

A Swab sticks

B All-glass syringes

C Oils and jellies

D All of these

ANS:D - All of these

Give the description for the answer.

Q12: Which of the following is best to sterilize heat labile solutions?

A Dry heat

B Autoclave

C Membrane filtration

D Pasteurization

ANS:C - Membrane filtration

This is because all of the mentioned ways can result in disruption of the membrane since heat is involved except for filtration which only using a membrane to filter the microbes.

Q13: Which of the following items could be sterilized by dry heat sterilization?

A Intravenous (IV) solution

B Plastic IV bags

C Glass pipettes

D rubber gloves

ANS:C - Glass pipettes

Dry heat can be used to sterilize glassware, powders and oils. Dry heat is not suitable for heat sensitive materials such as plastic and rubber.

Q14: The time required to kill 90% of the microorganisms in a sample at a specific temperature is the

A decimal reduction time

B thermal death point

C F value

D D value

ANS:D - D value

The D-value, which denotes the decimal reduction time, is the time required at a specific temperature and under specified conditions to reduce a microbial population by 90% it could also be denoted as decimal reduction time.

Q15: The lowest temperature that kills all microorganisms in a liquid suspension in 10 minutes is known as the

A decimal reduction time

B thermal death point

C thermal death temperature

D thermal death time

ANS:B - thermal death point

No answer description is available.

Q16: Which of the following substances can sterilize?

A Alcohol

B Cetylpyridinium chloride

C Ethylene oxide

D Chlorine

ANS:C - Ethylene oxide

No answer description is available.

Q17: Which of the following compounds are commonly used as general antiseptics to treat cuts and scratches?

A Aldehydes

B Ethylene oxide

C Halogens

D None of these

ANS:C - Halogens

No answer description is available.

Q18: Ethylene oxide is used to destroy or kill which of the following microbes?

A Bacteria

B Spores

C Fungi

D All of these

Q19: Milk is pasteurized in batch method by keeping it at

A 63°C for 30 minutes

B 72°C for 60 seconds

C 73°C for 30 minutes

D 72°C for 6 minutes

ANS:A - 63°C for 30 minutes

This is the holder method of pasteurization.

Q20: Which of the following describes the effect of ionizing radiation on microbes?

A Changes the 3-dimensional structure of proteins to a 2-dimen-sional form

B Substantially decreases enzymatic activity, slowing microbial reproduction

C Induces electrons and protons to jump out of the molecules of the microbe

D None of the above

ANS:C - Induces electrons and protons to jump out of the molecules of the microbe

No answer description is available.

Q21: Which of the following material is sterilized by use of red heat?

A Soiled dressings

B Inoculating wires and loops

C Glass slides

D All-glass syringes

ANS:B - Inoculating wires and loops

No answer description is available.

Q22: Which of the following skin disinfectant(s) is/are most frequently used?

A Isopropyl alcohol

B Ethyl alcohol

C Both (a) and (b)

D none of these

ANS:C - Both (a) and (b)

No answer description is available.

Q23: One drawback to the use of ultraviolet light as a sterilizing agent is its

A failure to kill bacteria

B failure to bacterial spores

C failure to kill microbes in a closed environment

D failure to kill microbes located in the center of an object

ANS:D - failure to kill microbes located in the center of an object

How come? Explain.

Q24: Bactericidal concentration of phenol is

A 0.25%

B 0.5%

C 0.75%

D 1%

ANS:D - 1%

No answer description is available.

Q25: Preservation of foods by using salts and sugars works by

A raising pH

B lowering osmotic pressure

C creating a hypertonic environment

D creating a hypotonic environment

ANS:C - creating a hypertonic environment

No answer description is available.

Q26: Microbes can be removed from a liquid solution by the process of

A filtration

B freeze-drying

C osmosis

D desiccation

ANS:A - filtration

No answer description is available.

Q27: All of the following are sporicidal except

A glutaraldehyde

B ethylene oxide

C formaldehyde

D alcohol

ANS:D - alcohol

No answer description is available.

Q28: Ethylene oxide is used to destroy or kill which of the following microbes?

A Bacteria

B Spores

C Fungi

D All of these

Q29: Steam exposure of a material at 100°C for 20 minutes for three consecutive days is known as

A inspissation

B tyndallization

C autoclaving

D none of these

ANS:B - tyndallization

No answer description is available.

Q30: A(n)____is used to prevent infection by killing or inhibiting pathogen growth on animal tissues.

A bacteriostatic agent

B sanitizer

C disinfectant

D antiseptic

ANS:D - antiseptic

Why not be option A? Please explain.

Q31: Which of the following process can be efficiently carried out by incineration?

A Sterilization of scalpel blades and needles

B Sterilization of all glass syringes

C Sterilization of points of forceps

D Destruction of contaminated materials

ANS:D - Destruction of contaminated materials

No answer description is available.

Q32: Which disinfectant was the most effective against Salmonella"?

A Phenol

B Cetylpyridinium chloride

C Hexachlorophene

D Merthiolate

ANS:D - Merthiolate

No answer description is available.

Q33: Which of the following disinfectants act by disrupting microbial membranes?

A Cationic detergents

B Halogens

C Heavy metals

D Aldehydes

ANS:A - Cationic detergents

Very useful. Thanks for proving it.

Q34: Which of the following tests is designed to simulate the natural conditions under which the disinfectants are used in hospitals?

A Phenol coefficient test

B Minimum inhibitory concentration test

C Capacity test

D None of these

ANS:C - Capacity test

No answer description is available.

Q35: Which of the following is most effective for sterilizing mattresses and plastic petri plates?

A Chlorine

B Ethylene oxide

C Glutaraldehyde

D Ultraviolet radiation

ANS:B - Ethylene oxide

UV should be the right answer

Q36: Which of the following is best used for long term storage of microbial samples when carried out properly?

A Storage in a freezer at -10°C

B Storage in a freezer at ultra low temperatures (-70°C)

C Storage in a refrigerator on an agar slant

D Storage on a petri plate at room temperature

ANS:B - Storage in a freezer at ultra low temperatures (-70°C)

No answer description is available.

Q37: Iodophores are mixture of

A iodine and aldehydes

B iodine and surface active agents

C iodine and alcohols

D iodine and phenols

ANS:B - iodine and surface active agents

No answer description is available.

Q38: The organisms retained in the fluids filtered by Seitz filter is

A Proteus

B Staphylococcus

C Clostridium

D None of these

ANS:D - None of these

No answer description is available.

Q39: For sterilization of which material gamma rays can be used?

A Catheters

B Plastic syringes

C Canulas

D None of these

ANS:D - None of these

According to me, Option (B) plastic syringes should be correct answer

Q40: Ethylene oxide is used to destroy or kill which of the following microbes?

A Bacteria

B Spores

C Fungi

D All of these

ANS:D - All of these

No answer description is available.

Q41: Which of the following is not a disinfectant containing a heavy metal?

A Silver nitrate

B Mercurochrome

C Copper sulfate

D Chlorine

ANS:D - Chlorine

No answer description is available.

Q42: Media containing spores and thermolabile constituents are sterilized by

A pasteurization

B UV radiation

C dry heat

D tyndalization

ANS:B - UV radiation

Why can't Tyndallization also be the answer?

Please explain the answer in detail.

Q43: Sweet and salty foods frequently don't require refrigeration to prevent spoilage because they have

A insufficient nutrients

B low pH

C high concentration of solutes

D toxic alkaline chemicals

ANS:C - high concentration of solutes

No answer description is available.

Q44: Which is the most important surface active disinfectants?

A Amphoteric compounds

B Cationic compounds

C Non-ionic compounds

D Anionic compounds

ANS:B - Cationic compounds

B. Cationic compounds is the right answer.

Q45: Complete destruction of the microorganisms is commonly known as

A disinfection

B sterilization

C antisepsis

D none of these

ANS:C - antisepsis

It should be sterilization.

Q46: Which of the following is sterilized with the help of glutaraldehyde?

A Thermometers

B Bronchoscopes

C Cystoscopes

D All of these

ANS:D - All of these

No answer description is available.

Q47: Which of the following methods will not sterilize?

A Aqueous glutaraldehyde for 10 hours

B Dry heat at 171°C for 1 to 2 hours

C 121°C at 15 lb/in pressure for 15 to 20 minutes

D 100°C boiling water for 30 minutes

ANS:D - 100°C boiling water for 30 minutes

No answer description is available.

Q48: Ethylene oxide is used to destroy or kill which of the following microbes?

A Bacteria

B Spores

C Fungi

D All of these

Q49: The process of making an object free from living organisms including bacterial and fungal spores and viruses is known as

A pasteurization

B antisepsis

C disinfection

D sterilization

ANS:D - sterilization

Sterilization is the process of making the object free from living microbes.

Q50: Which of the following is a limitation of the autoclave?

A It takes too long to sterilize

B It lacks the ability to inactivate viruses

C It lacks the ability to kill endospores

D It will destroy heat labile materials

ANS:D - It will destroy heat labile materials

No answer description is available.

Q51: The time in minutes at a specific temperature needed to kill a population of cells is the

A decimal reduction time

B thermal death point

C thermal death temperature

D F value

ANS:D - F value

No answer description is available.

Q52: Which of the following has most heat resistant spores?

A Clostridium histolyticum

B Clostridium perfringens

C Bacillus stearothermophilus

D Bacillus cereus

ANS:C - Bacillus stearothermophilus

No answer description is available.



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