Summer 2025 Exam 3 Study Guide - Chapter 13

Which of the following lists the ideal characteristics of a disinfectant?

• Broad-spectrum, fast-acting, non-toxic, stable

• Narrow-spectrum, slow-acting, toxic, unstable

• Only effective against viruses, corrosive, unstable

• Requires high concentration, leaves residue, unstable

Considerations when choosing a chemical method for antimicrobial control include:

• Effectiveness, safety, and compatibility with materials

• Only the color of the chemical

• The taste of the chemical

• The price alone

Tags

NGSS.HS-ETS1-3

The D-value stands for which of the following, and what is it a measurement of?

• Decimal reduction time; it measures the time required at a certain temperature to kill 90% of microorganisms.

• Density value; it measures the mass per unit volume of a substance.

• Dilution value; it measures the concentration of a solution.

• Diffusion value; it measures the rate at which a substance spreads.

Some targets of disinfectants include:

• cell membranes

• plant roots

• animal fur

• glass surfaces

Tags

NGSS.MS-PS1-2

Enveloped or nonenveloped viruses: Which are more susceptible to disinfectants and why?

• Enveloped viruses are more susceptible because their lipid envelope is easily disrupted.

• Nonenveloped viruses are more susceptible because they lack a protective envelope.

• Enveloped viruses are more resistant because their envelope protects them.

• Nonenveloped viruses are more resistant because their proteins are easily destroyed.

What are the different BSL levels? Examples? Which ones are handled in our lab?

• BSL-1 to BSL-4 are the different levels; BSL-1 is typically handled in our lab.

• BSL-1 and BSL-2 are the only levels; our lab handles BSL-4.

• BSL-3 and BSL-4 are the only levels; our lab handles BSL-1.

• Only BSL-4 exists; our lab handles BSL-3.

The most effective type of heat and its limitations are:

• Conduction is most effective, but limited to solids.

• Radiation is most effective, but limited to liquids.

• Convection is most effective, but limited to gases.

• All types of heat transfer are equally effective.

Pasteurization is:

• a process of heating liquids to kill harmful microorganisms

• a method of freezing food to preserve it

• a technique for fermenting dairy products

• a way to add flavor to beverages

The standard settings of the autoclave are demonstrated by which of the following? What is the setting?

• 121°C at 15 psi for 15 minutes

• 100°C at 1 atm for 10 minutes

• 140°C at 20 psi for 5 minutes

• 110°C at 10 psi for 30 minutes

Low temperature/refrigeration/freezing is effective as a method of killing microbes.

• It is not very effective at killing microbes, but slows their growth.

• It completely kills all microbes instantly.

• It is the most reliable method for sterilization.

• It increases the growth of microbes.