This set of Microbiology Multiple Choice Questions & Answers (MCQs) focuses on “Characteristics and Definition of Chemical Agents”.
1. A chemical agent that kills the microorganisms and is commonly applied to substances used on inanimate objects are _______________
a) Antiseptics
b) Sanitizer
c) Disinfectants
d) Antibiotics
View Answer
Explanation: Disinfectant is a chemical agent that kills the growing forms but not necessarily the resistant spore forms of disease-producing microorganisms. They are commonly applied to substances used on inanimate objects.
2. An agent that prevents the growth of bacteria are known as __________________
a) Bactericide
b) Bacteriostatic
c) Antimicrobial
d) Antibiotic
View Answer
Explanation: An agent that prevents or inhibits the growth of bacteria are known as bacteriostatic agents and the condition is known as bacteriostasis.
3. For using any chemical agent, we need to increase the temperature of the environment.
a) True
b) False
View Answer
Explanation: One of the characteristics of chemical agents is that they should be toxic to microorganisms at room or body temperature. In using the compound, it should not be necessary to raise the temperature beyond that normally found in the environment where it is to be used.
4. Which of the following is the characteristics of a sanitizer?
a) destroys all microbial forms
b) prevents the growth or action of microorganisms
c) reduces the microbial population to safe levels
d) kills all the bacteria and the bacterial spores
View Answer
Explanation: Sanitizer is an agent that reduces the microbial population to safe levels as prescribed by public health requirements. Usually it is a chemical agent that kills 99.9% of the growing bacteria and are generally applied to inanimate objects.
5. Which of the following is not a chemical agent for microbial control?
a) Radiations
b) Antibiotics
c) Antiseptics
d) Germicide
View Answer
Explanation: Radiations are physical agents for microbial control and include ionizing as well as non-ionizing radiations to kill the microorganisms.
6. Escherichia coli is much more resistant to cationic disinfectants than Staphylococcus aureus.
a) True
b) False
View Answer
Explanation: Chemical agents are not all equally effective against bacteria, fungi, and other microorganisms. Differences exist between Gram-positive and Gram-negative bacteria:
Escherichia coli is much more resistant to cationic disinfectants than Staphylococcus aureus.
7. The process of killing all microorganisms along with their spores is ____________________
a) Disinfection
b) Antisepsis
c) Sanitization
d) Sterilization
View Answer
Explanation: Sterilization is the process of destroying all forms of microbial life. The term sterilization refers to the complete absence or destruction of all microorganisms and should not be used in a relative sense.
8. Which of the following are generally applied on living animal tissues?
a) Antiseptics
b) Disinfectants
c) Preservatives
d) Sanitizer
View Answer
Explanation: Antiseptics are substances that opposes sepsis,i.e., prevents the growth or action of microorganisms either by destroying microorganisms or by inhibiting their growth and metabolism. They are usually applied on living animal tissues.
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