Question 1

The destruction of all microorganisms and their endospores is referred to as
A)disinfection.
B)degermination.
C)sanitization.
D)sterilization.

Accepted Answer

Sterilization is the only option that completely eliminates all microorganisms and their endospores. Disinfection, degermination, and sanitization do not necessarily eliminate all microorganisms and their endospores.

Question 2

Which of the following media is often used to grow Mycobacterium tuberculosis?
A)Blood agar
B)MacConkey agar
C)Heart infusion broth
D)Middlebrook's medium

Accepted Answer

Middlebrook's medium is specifically designed for the growth of Mycobacterium tuberculosis and is the most commonly used medium for this purpose. Blood agar is a general-purpose medium used for the growth of many types of bacteria, while MacConkey agar is selective for gram-negative bacteria and cannot be used for the growth of Mycobacterium tuberculosis. Heart infusion broth is a nutrient-rich medium that supports the growth of a wide variety of microorganisms but is not selective for Mycobacterium tuberculosis.

Question 3

An inanimate object or substance capable of transporting pathogens from one medium or individual to another is referred to as a
A)vector.
B)fomite.
C)transporter.
D)transposon.

Accepted Answer

A fomite is an inanimate object or substance that can harbor and transmit infectious pathogens. Examples include doorknobs, clothing, and bedding. Vectors, on the other hand, are live animals that transmit pathogens, and transposons are genetic elements that can move within a genome. The term "transporter" does not specifically refer to a means of disease transmission.

Question 4

Which of the following is considered to be a macronutrient for microorganisms?
A)Folic acid
B)Nitrogen
C)Copper
D)Riboflavin

Accepted Answer

Nitrogen is considered a macronutrient for microorganisms as it is required in relatively large quantities for protein synthesis, DNA replication, and other essential metabolic processes. Folic acid, copper, and riboflavin are considered micronutrients, which are required in smaller quantities.

Question 5

In an agar slant,bacterial colonies that appear separate or semiconfluent are referred to as
A)filiform.
B)echinulate.
C)beaded.
D)effuse.

Accepted Answer

Beaded colonies on an agar slant refer to those that appear separate or semiconfluent, resembling beads strung along the inoculation line.

Question 6

A saucer-shaped liquefaction in a gelatin stab is referred to as
A)napiform.
B)saccate.
C)crateriform.
D)stratiform.

Accepted Answer

A saucer-shaped liquefaction in a gelatin stab is referred to as crateriform.

Question 7

The process by which the numbers of microbes on the human skin are reduced by scrubbing is called
A)degermination.
B)sanitization.
C)disinfection.
D)sterilization.

Accepted Answer

Degermination is the process of reducing the number of microbes on the skin surface by scrubbing or using antimicrobial agents. Sanitization is the reduction of microbial populations to a safe level. Disinfection and sterilization are more extensive processes that eliminate or destroy all microorganisms. Therefore, degermination is the best choice based on the given options.

Question 8

Which of the following is a biological test organism for validating dry or moist heat sterilization?
A)Bacillus subtilis var.niger
B)Escherichia coli
C)Staphylococcus aureus
D)Staphylococcus epidermidis

Accepted Answer

Bacillus subtilis var. niger is commonly used as a biological test organism for validating both dry and moist heat sterilization processes. It is a spore-forming bacterium that is highly resistant to high temperatures, making it a suitable organism for testing the effectiveness of different sterilization methods. Escherichia coli and Staphylococcus species are not typically used for validation of heat sterilization processes.

Question 9

Which of the following genera of bacteria need very specialized media for culturing?
A)Spiroplasma
B)Enterococcus
C)Staphylococcus
D)Pseudomonas

Accepted Answer

Spiroplasma is a genus of bacteria that require specialized media for culturing, unlike the other genera mentioned in the options. Spiroplasma bacteria are known for their helical shape and lack of cell walls. They are commonly found in insects and other arthropods.

Question 10

Chemically,agar is a
A)protein.
B)lipid.
C)carbohydrate.
D)nucleic acid.

Accepted Answer

Agar is a type of complex polysaccharide carbohydrate that is commonly used in microbiology laboratories for growing various microorganisms.

Question 11

Which of the following stains is generally used for the diagnosis of tuberculosis?
A)Acid-fast stain
B)Gram stain
C)Negative stain
D)Simple stain

Accepted Answer

Acid-fast stain is used for the diagnosis of tuberculosis. The acid-fast staining technique is based on the property of mycobacterial cell walls to retain carbol fuchsin (a dye) in the presence of acid and alcohol, whereas other microorganisms lose the dye. Hence, acid-fast staining helps in the identification of acid-fast bacilli (AFB) that are responsible for tuberculosis. Gram stain is not used for the diagnosis of tuberculosis as mycobacteria are resistant to this technique. Negative stain and simple stain are not commonly used for the diagnosis of tuberculosis.

Question 12

Which of the following microorganisms can be cultured only in the footpads of mice or a species of armadillo?
A)Mycobacterium tuberculosis
B)Mycobacterium leprae
C)Neisseria gonorrhoeae
D)Mycoplasma

Accepted Answer

Mycobacterium leprae, the causative agent of leprosy, cannot be cultured in laboratory media and can only be grown in the footpads of mice or in the nine-banded armadillo. The other microorganisms listed can be cultured in laboratory media.

Question 13

Which of the following media are defined and have an exact chemical composition?
A)Complex media
B)Synthetic media
C)Enriched media
D)Special media

Accepted Answer

Synthetic media are defined and have an exact chemical composition as they are prepared by adding precise amounts of purified chemicals and nutrients. Complex media, enriched media, and special media do not have an exact chemical composition as they contain various components of unknown quantities and sources.

Question 14

Which of the following stains is the most widely used differential stain in hematology laboratories?
A)Carbolfuchsin stain
B)Ziehl-Neelson stain
C)Kinyoun stain
D)Wright's stain

Accepted Answer

Wright's stain is the most widely used differential stain in hematology laboratories. It is used for staining blood cells and helps in identifying various types of cells and their morphology. Carbolfuchsin, Ziehl-Neelson, and Kinyoun stains are primarily used for staining bacterial cells.

Question 15

Which of the following is a general-purpose medium?
A)Tryptic soy agar
B)Blood agar
C)Mannitol salt agar
D)MacConkey agar

Accepted Answer

Tryptic soy agar is a general-purpose medium that can support the growth of a wide range of organisms due to its nutrient-rich composition. Blood agar and Mannitol salt agar are both selective mediums, while MacConkey agar is a differential medium.

Question 16

The stain used to identify bacteria with a large amount of peptidoglycan in their cell walls is the
A)acid-fast stain.
B)methylene blue stain.
C)Gram stain.
D)negative stain.

Accepted Answer

The Gram stain is used to identify bacteria with a large amount of peptidoglycan in their cell walls. This staining method differentiates between Gram-positive bacteria (which have a thick peptidoglycan layer and appear purple) and Gram-negative bacteria (which have a thin peptidoglycan layer and appear pink). The acid-fast stain is used for detecting bacteria with a waxy cell wall, methylene blue stain is a general stain used for observing bacterial morphology, and negative stain is used to view capsules and spores.

Question 17

Which of the following media is used to isolate Neisseria gonorrhoeae?
A)Phenylethyl alcohol agar
B)Thayer-Martin agar
C)MacConkey agar
D)Mannitol salt agar

Accepted Answer

Thayer-Martin agar is the best choice for isolating Neisseria gonorrhoeae as it contains antibiotics that specifically inhibit the growth of other bacteria, allowing for the selective growth of N. gonorrhoeae. Phenylethyl alcohol agar, MacConkey agar, and Mannitol salt agar are not suitable for the isolation of N. gonorrhoeae.

Question 18

Nigrosin is a stain used in
A)simple staining.
B)gram staining.
C)negative staining.
D)acid-fast staining.

Accepted Answer

Nigrosin is a negative stain, which means it stains the background instead of the cells or structures being viewed under the microscope. It is commonly used to visualize bacterial capsules and spirochetes.

Question 19

In correct sequence,the five "I's" in microbiology stand for
A)Inoculation, Inspection, Identification, Incubation, and Isolation.
B)Isolation, Inoculation, Inspection, Identification, and Incubation.
C)Inoculation, Incubation, Isolation, Inspection, and Identification.
D)Inspection, Inoculation, Incubation, Isolation, and Identification.

Accepted Answer

The correct sequence of the five "I's" in microbiology is inoculation, incubation, isolation, inspection, and identification. Choice C is the only one that presents the correct sequence in the right order.

Question 20

Media that contain complex organic substances such as blood for the growth of specific bacteria are referred to as
A)enriched media.
B)general-purpose media.
C)differential media.
D)reducing media.

Accepted Answer

Enriched media are commonly used in microbiology to grow fastidious bacteria that cannot grow on general-purpose media. These media contain complex organic substances such as blood, serum, or yeast extract that provide additional nutrients for the growth of bacteria.

Quiz 8: Microbiological Laboratory Techniques

The destruction of all microorganisms and their endospores is referred to as

Which of the following media is often used to grow Mycobacterium tuberculosis?

An inanimate object or substance capable of transporting pathogens from one medium or individual to another is referred to as a

Which of the following is considered to be a macronutrient for microorganisms?

In an agar slant,bacterial colonies that appear separate or semiconfluent are referred to as

A saucer-shaped liquefaction in a gelatin stab is referred to as

The process by which the numbers of microbes on the human skin are reduced by scrubbing is called

Which of the following is a biological test organism for validating dry or moist heat sterilization?

Which of the following genera of bacteria need very specialized media for culturing?

Chemically,agar is a

Which of the following stains is generally used for the diagnosis of tuberculosis?

Which of the following microorganisms can be cultured only in the footpads of mice or a species of armadillo?

Which of the following media are defined and have an exact chemical composition?

Which of the following stains is the most widely used differential stain in hematology laboratories?

Which of the following is a general-purpose medium?

The stain used to identify bacteria with a large amount of peptidoglycan in their cell walls is the

Which of the following media is used to isolate Neisseria gonorrhoeae?

Nigrosin is a stain used in

In correct sequence,the five "I's" in microbiology stand for

Media that contain complex organic substances such as blood for the growth of specific bacteria are referred to as