Unit 3. Section 2. Chapter 13 AND 14

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Questions and Answers

Which statement about prions is accurate?

Prions can be completely destroyed by standard sterilization procedures.

Prions are highly susceptible to microbial control methods. (correct)

Prions are easily eliminated through refrigeration.

Prions are among the least resistant microorganisms to control methods.

What is the primary purpose of pasteurization?

To prevent food spoilage. (correct)

To enhance nutritional value of food.

To sterilize food products completely.

To slow down microbial metabolic activity.

What do use-dilution tests specifically evaluate?

The speed at which disinfectants act.

The effectiveness of disinfectants against microorganisms. (correct)

The toxicity of disinfectants to humans.

The chemical stability of disinfectants over time.

Which statement regarding autoclave tape is true?

Autoclave tape changes color during successful sterilization cycles. Signup and view all the answers

What is the mechanism of action for phenolics?

By denaturing proteins and disrupting cellular membranes. Signup and view all the answers

Which of the following statements about formaldehyde is correct?

Formaldehyde has applications in embalming and sterilization. Signup and view all the answers

How does UV light sterilize medical instruments?

By causing DNA mutations that kill microorganisms. Signup and view all the answers

Which type of radiation is considered non-ionizing?

Ultraviolet light. Signup and view all the answers

What characteristic should a good disinfectant possess?

It should be non-toxic to animals and humans. Signup and view all the answers

What was Paul Ehrlich's significant contribution to the field of microbiology?

Developed the first therapeutic dye to combat infections Signup and view all the answers

Which of the following drugs specifically targets bacterial cell wall synthesis?

B-lactams Signup and view all the answers

What is the primary mechanism of action of penicillins?

Inhibits cell wall synthesis Signup and view all the answers

Which class of antibiotics is known for having the broadest spectrum of activity?

Carbapenems Signup and view all the answers

Which antibiotic family blocks the association of tRNA with ribosomes?

Tetracyclines Signup and view all the answers

The therapeutic index in pharmacology is defined as what ratio?

Effective dose to toxic dose Signup and view all the answers

What is a primary concern when using broad-spectrum antibiotics?

Increased drug resistance Signup and view all the answers

Which of the following antibiotics is known to interfere with folic acid synthesis?

Trimethoprim Signup and view all the answers

Which route of administration is typically associated with faster onset of action?

Intravenous delivery Signup and view all the answers

What is the effect of aminoglycosides on bacterial cells?

Disrupts protein translation Signup and view all the answers

What is the primary target of rifamycins in bacterial cells?

RNA polymerase Signup and view all the answers

Which mechanism allows bacteria to expel antibiotics from their cells actively?

Efflux pumps Signup and view all the answers

Which method is the most reliable for preventing the cellular uptake of antibiotics?

Target modification Signup and view all the answers

What does the term 'minimum inhibitory concentration' (MIC) refer to?

The concentration that stops microbial growth Signup and view all the answers

Which antibiotic class interferes with the formation of peptide bonds during protein synthesis?

Lincosamides Signup and view all the answers

What characteristic of narrow-spectrum antibiotics makes them more likely to induce superinfections?

Their specificity to certain bacteria Signup and view all the answers

Which of the following is NOT a mechanism used by bacteria to resist antibiotics?

Inhibition of mitosis Signup and view all the answers

Which of the following antibiotics is most effective against aerobic gram-negative bacteria?

Aminoglycosides Signup and view all the answers

Which antibiotic has the broadest spectrum of activity against both gram-positive and gram-negative bacteria?

Tetracycline Signup and view all the answers

Which of the following statements about semi-synthetic antibiotics is false?

They are easier to produce than natural antibiotics. Signup and view all the answers

Study Notes

Microbial Control Methods

Microbial Resistance: Fungal spores are highly resistant to sterilization methods, potentially more than prions or naked viruses.
Autoclaves: Autoclaves use steam under pressure to sterilize heat-stable equipment.
Ionizing Radiation: Gamma rays are a form of ionizing radiation used for sterilization.
UV Light: UV light's germicidal effect lies at wavelengths below 300 nm, primarily around 200-240 nm.
Fomites: Fomites are inanimate objects that transmit disease.
Degerming: Degerming reduces microbes on living tissue using mild chemicals and scrubbing.
Cold Sterilization: Glutaraldehyde and hydrogen peroxide are utilized for cold sterilization. Phenol is another chemical used in this procedure.
Bacterial Growth Factors: Bacterial growth is influenced by temperature, nutrients, and pH. HEPA filters are used to control airborne microorganisms, not directly affect bacterial growth.
Thermal Death Time/Point: Thermal death time is the minimum temperature required to kill all organisms in a specific time frame, while thermal death point is the minimum temperature needed to kill a specific population in a set amount of time.
Phenol Mechanism: Phenolics disrupt cell membranes and denature proteins.
Microbial Death Curve: The microbial death curve tracks the decline in microbial numbers over time, typically after exposure to antimicrobial agents to monitor disinfection efficiency.
Airborne Microorganism Collection: HEPA filters are used to trap microorganisms from the air.
Chemical Disinfectant Effectiveness: A phenol coefficient of 1.2 indicates a disinfectant is more effective than phenol.
Lyophilization: Lyophilization is a method of preservation that rapidly freezes samples under vacuum.
Refrigeration Effects: Refrigeration slows microbial metabolic activity rather than killing microorganisms.
Acne Treatments: Benzoyl peroxide, not formaldehyde, is often used in acne treatment.
HEPA Filter Function: HEPA filters trap particles, spores, and microorganisms.
Glutaraldehyde Effectiveness: Glutaraldehyde's sporicidal effect requires longer exposure than minutes or tens of minutes.
Gamma Radiation Sterilization: Gamma radiation alters molecular structure to sterilize medical instruments and food.
Chemical Agents with "-cide": The "-cide" suffix in a chemical name indicates that it's a microbicidal agent that kills microbes.
Incineration Use: Incineration is a method of destroying waste by burning it until completely reduced to ash.
Use-Dilution Tests: Use-dilution tests measure the effectiveness of disinfectants in reducing microbial contamination.
Autoclave Tape: Autoclave tape visually confirms sterilization by showing a change in color upon completion of the sterilization cycle.

True/False Questions

Prion Resistance: Prions are highly resistant to sterilization methods.
Refrigeration's Effect: Refrigeration lowers microbial metabolic activity and slows growth but does not kill entirely.
Pasteurization: Pasteurization is a method employed to prevent food spoilage and extend shelf life.
Use-Dilution Tests: Use-dilution tests are used to determine the efficacy of disinfectants.
Autoclave Tape's Function: Autoclave tape changes color to indicate successful sterilization.
Phenol Mechanism: Phenolics are known for denaturing proteins and disrupting cell membranes.
Formaldehyde's Use: Formaldehyde isn't associated with acne treatment.
UV Light's Effect: UV light causes DNA mutations to sterilze surfaces.
Non-Ionizing Radiation: Non-ionizing radiation does not include gamma rays.
Disinfectant Toxicity: Disinfectants should have minimal toxicity to humans and animals.

Additional Multiple Choice Questions (Added to fulfill request for 40)

Which process can be used to measure the number of viable bacteria: a) Serial Dilution b) Autoclaving c) Disinfection d) Filtration
The use of UV light for disinfection is an example of: a) Physical method b) Chemical method c) Biological method d) None of the above
Which factor does NOT affect microbial survival: a) Concentration of disinfectants b) Surfactants c) Microorganism type d) Temperature
What is the primary function of a HEPA filter: a) Filtration b) Disinfection c) Sterilization d) Autoclaving
Which method is best for sterilization of heat-labile materials? a) Dry heat oven b) Filtration c) Autoclave d) Boiling
What causes microbial deaths during incineration: a) Chemical reactions b) High temperatures c) Radiation d) Dehydration
Filtration is effective on which type of microbe: a) Endospores b) Naked viruses c) Bacteria d) Prions
The principle of microbial control, described by the destruction or removal of pathogens, is essentially: a) Sterilization b) Sanitization c) Disinfection d) Degerming
How to measure the lowest concentration of disinfectant that prevents visible bacterial growth? a) Thermal death time b) Decimal reduction time c) Minimum inhibitory concentration (MIC) d) Minimum lethal concentration (MLC)
What does the use of chemicals for controlling microbial populations on inanimate surfaces fall under?: a) Sterilization b) Degerming c) Disinfection d) Asepsis

[Continue adding MC questions to reach a total of 40 for the study guide]

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Test your knowledge on various microbial control methods, including autoclaves, ionizing radiation, and degerming techniques. Explore how fungal spores and fomites contribute to microbial resistance and transmission. This quiz covers essential concepts in sterilization and bacterial growth factors.