Question 1

The RN understands that along with a pH test, a microscopic view is needed to perform the ferning test to detect an amniotic fluid leak. The patient sample is prepared on a glass slide and examined under 10x magnification. Which type of microscope will be used to make this observation of the patient sample?

Accepted Answer

The ferning test requires a light microscope to observe the patient sample on a glass slide under 10x magnification. Electron microscopes are used to observe extremely small structures and require special preparatory techniques. Confocal and fluorescent microscopes are more advanced and specialized types of light microscopes used for specific applications.

Question 2

When utilizing a light microscope, the specimen on the glass slide must be in proper position to ensure illumination of the specimen for visualization. The glass slide is placed in which of the following positions?

Accepted Answer

The glass slide must be placed between the condenser lens and the objective lens to ensure proper illumination of the specimen. This allows the light to pass through the specimen on the glass slide before being magnified by the objective lens.

Question 3

Fixed smears of specimens are required in order to perform the Gram stain and endospore stain on the specimens.

Accepted Answer

Fixed smears are necessary for both the Gram stain and endospore stain procedures in order to properly visualize and differentiate bacterial cell structures.

Question 4

A sputum sample is ordered for microbial analysis in order to rule out the diagnosis of tuberculosis. Suspecting Mycobacterium tuberculosis may be the pathogen, the RN knows the laboratory technicians will perform which stain on the sample?

Accepted Answer

Acid-fast stain is used to detect Mycobacterium tuberculosis because it has a unique cell wall that contains mycolic acid which resists decolorization by acid-alcohol. This makes them appear red/pink on a stained slide under a microscope. Endospore stain is used for endospore-forming bacteria, negative stain is used for observing capsules, and flagellar stain is used for observing bacterial flagella.

Question 5

The relationship between a micrometer and a millimeter is ________.

Accepted Answer

A millimeter is equal to 1,000 micrometers, meaning a micrometer is 1,000 times smaller than a millimeter.

Question 6

In the absence of immersion oil when using the 100x objective lens, some light would be lost to scatter resulting in a blurry image.

Accepted Answer

Immersion oil is important for maximizing the amount of light that reaches the objective lens and decreasing light scatter, which can result in a clearer image. Without immersion oil, light scatter would increase and the image would appear blurry.

Question 7

The patient's culture results positive for Staphylococcus. The RN understands that the culture most likely required growth on a complex medium, consisting of

Accepted Answer

Staphylococcus is a complex bacterium that requires a complex medium to grow. A complex medium consists of at least one ingredient that is not chemically defined, such as blood, serum, or yeast extract. This allows for the growth of various microorganisms that have different nutrient requirements. Additionally, a complex medium may contain various chemical growth promoters, but not inhibitors. Therefore, the best choice is C, at least one ingredient that is not chemically defined.

Question 8

The diameter of field for a 4x lens is measured at 4.6 mm. How many bacterial cells, each measuring 4 μm, could be lined up along the diameter?

Accepted Answer

To find out how many bacterial cells can be lined up along the diameter, divide the diameter of the field (4.6 mm) by the size of one bacterial cell (4 μm). First, convert the diameter from millimeters to micrometers: 4.6 mm = 4600 μm. Then, divide by the size of one cell: 4600 μm / 4 μm/cell = 1150 cells.

Question 9

A confocal microscope uses visible light as its source of illumination.

Accepted Answer

The answer of A confocal microscope uses visible light as...

Question 10

At the end of the Gram stain, gram-positive bacteria will be seen as red/pink cells.

Accepted Answer

Gram-positive bacteria will actually appear as purple/blue cells after the Gram stain, while gram-negative bacteria will appear as red/pink cells.

Question 11

Comparing defined vs. complex media is analogous to comparing ________.

Accepted Answer

Defined media are synthesized with known amounts and types of nutrients, whereas complex media contain ingredients of unknown composition and quantity. This is analogous to breast milk, which has a defined composition of nutrients, while formula has a complex mixture of ingredients.

Question 12

The all-purpose media Tryptic Soy Agar (TSA) contains the following four ingredients; pancreatic digest of casein, digest of soybean meal, NaCl and agar. TSA is best described as ________.

Accepted Answer

Tryptic Soy Agar (TSA) is a complex media because it contains a variety of nutrient sources, such as pancreatic digest of casein and digest of soybean meal, which provide a mixture of amino acids, peptides, and other organic compounds to support the growth of a wide range of microorganisms. TSA is not designed to selectively enrich or differentiate specific microbial groups, nor is it a defined or reducing media.

Question 13

Culturing of the sputum resulted in the growth of distinct colonies and further isolation by subculturing is now needed. The RN understands that isolation is accomplished by taking a bit of growth from an individual colony and inoculating a separate medium, resulting in the production of a(n) ________.

Accepted Answer

Isolating a bit of growth from an individual colony and inoculating a separate medium results in the production of a pure culture.

Question 14

The patient asks how microbes from her body can be grown in the lab. The RN explains that specimens are introduced to nutrient medium and that any growth of the microbe that appears after incubating the specimen is called the ________.

Accepted Answer

The process of introducing a specimen to nutrient medium and allowing any resulting growth to occur is known as culturing. The growth itself is referred to as a culture. Therefore, the correct answer is B.

Question 15

The patient is diagnosed with a bacterial infection after gram-positive cocci are detected in the fluid sample. The Gram stain involves ________.

Accepted Answer

Gram staining involves timed, sequential applications of crystal violet dye, iodine, an alcohol rinse, and a contrasting counterstain to the sample. This differentiates bacteria into two major categories of gram-positive (purple) and gram-negative (pink) based on differences in their cell wall composition.

Question 16

Microscopic analysis revealed the presence of grapelike clusters of gram-positive cocci. The RN educates the patient that the species identification of the organism will require biochemical testing, which aids in microbial identification by providing information on cellular metabolism. Which of the following statements by the patient demonstrates understanding of the nurse's teaching?

Accepted Answer

The answer of Microscopic analysis revealed the presence of grapelike...

Question 17

The real image is the reverse of the actual specimen.

Accepted Answer

The answer of The real image is the reverse of...

Question 18

The sterile vaginal fluid specimen is sent for culture. The RN educates the patient about the five basic techniques utilized by laboratory technicians to manipulate, grow, examine, and characterize any microorganisms present in the specimen. Which of the following is the correct order of steps for processing the specimen?

Accepted Answer

The correct order of steps for processing a specimen is inoculation, incubation, isolation, inspection, and identification. Inoculation refers to the transfer of the specimen onto a culture medium, incubation is the process of allowing the microorganisms to grow and multiply, isolation refers to separating different types of microorganisms that may be present, inspection involves examining the colonies to determine their characteristics, and identification involves using additional tests to identify the specific microorganism present.

Question 19

Ms. Hungh's acid-fast stain results resulted as inconclusive for the presence of acid-fast bacilli. Culturing of the sputum is performed in order to isolate microbial growth for further analysis. Lowenstein-Jensen medium is utilized to select for the growth of Mycobacterium species if present in the sample, while suppressing unwanted background organisms. What is the proper term for this type of medium?

Accepted Answer

The proper term for this type of medium is selective medium because it selects for the growth of a specific species (in this case, Mycobacterium) while inhibiting the growth of other organisms. Although Lowenstein-Jensen medium does have some differential properties, such as the ability to distinguish between different species of Mycobacterium based on their colony morphology, it is primarily considered a selective medium.

Question 20

Resolution differs from contrast in microscopy in that ________.

Accepted Answer

Resolution refers to the ability to distinguish two cells from one another, whereas contrast refers to the ability to distinguish a cell from its surroundings.

Quiz 2: Tools of the Laboratory: Methods for the Culturing and Microscopic Analysis of Microorganisms