Question 1

Which of the following magnifies the specimen to produce its real image?

Accepted Answer

The objective lens is responsible for magnifying the specimen to produce its real image, while the condenser focuses and directs the light onto the specimen, the ocular lens further magnifies the image and the body holds the objective lens and ocular lens in place. The nosepiece holds and rotates the objective lenses.

Question 2

Which type of microscope is the most widely used and shows cells against a bright background?

Accepted Answer

Bright field microscopes are the most commonly used type of microscope, and they use a bright background to illuminate the specimen, making it easier to see the cells.

Question 3

Magnification is achieved in a compound microscope through the initial magnification of the specimen by the _____ lens.This image is then projected to the _____ lens that will further magnify the specimen to form a virtual image received by the eye.

Accepted Answer

The initial magnification of the specimen is achieved through the objective lens, which is located close to the specimen. The image is then projected to the ocular lens, which will further magnify the specimen and form a virtual image that is received by the eye. Therefore, the correct answer is option C, which has the correct sequence of objective lens followed by the ocular lens.

Question 4

Which of the following characteristics refers to the microscope's ability to show two separate entities as separate and distinct?

Accepted Answer

Resolving power, also known as resolution, refers to the microscope's ability to distinguish two separate entities as separate and distinct. Magnification refers to the ability of the microscope to make an object appear larger than its actual size, and refraction refers to the bending of light as it passes through a medium.

Question 5

A rod-shaped bacterium is measured as 0.3 micrometers ($\mu$m)in length using an ocular micrometer.Your instructor wants you to report the length in millimeters (mm)to test your understanding of metric conversions.What is the length of the organism in millimeters?

Accepted Answer

To convert micrometers to millimeters, divide by 1000. Thus, 0.3 micrometers is 0.3/1000 = 0.0003 millimeters.

Question 6

Which of the following magnifies the specimen to produce its virtual image?

Accepted Answer

The ocular lens, also known as the eyepiece, magnifies the image formed by the objective lens to produce a virtual image for the observer to view.

Question 7

The _____ of the microscope holds and allows selection of the objective lenses.

Accepted Answer

The nosepiece holds and allows selection of the objective lenses.

Question 8

Which type of microscope shows cells against a bright background but also differentiates intracellular structures of unstained cells based on their varying densities?

Accepted Answer

Phase contrast microscopy uses differences in refractive index to create contrast in unstained specimens, allowing visualization of intracellular structures in live cells against a bright background.

Question 9

Differential media results in which of the following growth characteristics?

Accepted Answer

Differential media is designed to allow the growth of different types of microorganisms and produce visible differences between them. This can include differences in colony color, media color, precipitates, and gas bubbles. Therefore, all of the choices are correct.

Question 10

Bacteria that require special growth factors and complex nutrients are termed

Accepted Answer

Fastidious bacteria have complex nutritional requirements and require special growth factors. They cannot grow on standard nutrient media and require supplementation with specific nutrients. Aerobic, anaerobic, microaerophilic, and autotrophic refer to different aspects of bacterial physiology and are not related to nutritional requirements.

Question 11

A microbiologist must culture a patient's feces for intestinal pathogens.Which of the following would likely be present in selective media for analyzing this fecal specimen?

Accepted Answer

Bile salts are commonly added to selective media for fecal specimens to inhibit the growth of gram-positive bacteria and promote the growth of gram-negative pathogens such as Salmonella and Shigella. NaCl, sheep red blood cells, thioglycollic acid, and peptone are not typically added to selective media for this purpose.

Question 12

An enveloped virus measures 0.02 micrometers ($\mu$m)in diameter.What is the diameter of this virus in nanometers (nm)?

Accepted Answer

To convert micrometers (μm) to nanometers (nm), we multiply by 1000. Therefore, 0.02 μm is equal to 20 nm. Option B is the correct answer. Option A is too small, Option C is too large, and Option D is 1/10th the correct answer.

Question 13

All of the following are diameters of cells that would be resolved in a microscope with a 0.2 µm limit of resolution except

Accepted Answer

The answer of All of the following are diameters of...

Question 14

A reducing media is used to culture

Accepted Answer

A reducing media is used to culture anaerobic organisms. Anaerobic organisms require an environment with low oxygen concentration for growth, and reducing media creates this environment by removing oxygen and creating a reducing atmosphere.

Question 15

A microbiologist inoculates Staphylococcus aureus into a culture medium.Following incubation,both Staphylococcus aureus and Staphylococcus epidermidis are determined to be growing in this culture.What is the most likely explanation?

Accepted Answer

The presence of both Staphylococcus aureus and Staphylococcus epidermidis in the culture indicates that the culture has been contaminated, likely with multiple bacterial species.

Question 16

Newly inoculated cultures must be _____ at a specific temperature to encourage growth.

Accepted Answer

Newly inoculated cultures must be incubated at a specific temperature to encourage growth. Incubation provides the ideal conditions for microorganisms to grow and reproduce. Streaking and pouring are methods of inoculating cultures, while contamination is the opposite of what you want to happen during incubation. Therefore, the correct answer is C)incubated.

Question 17

The type of microscope in which you would see brightly illuminated specimens against a black background is

Accepted Answer

Dark field microscopy illuminates specimens with oblique angle light, making them appear bright against a dark background. This technique is particularly useful for observing live or unstained specimens that would not be visible under bright field microscopy.

Question 18

For which bacterial genus does mannitol salt agar differentiate between species?

Accepted Answer

Mannitol salt agar is a selective and differential medium that is used to differentiate between different species of Staphylococcus bacteria. The medium contains high concentrations of salt that inhibit the growth of other bacterial species, while the ability of certain Staphylococcus species to ferment mannitol produces acid that causes a pH indicator in the medium to turn yellow. Thus, Mannitol Salt Agar can differentiate between Staphylococcus species that can ferment mannitol and those that cannot.

Question 19

If a microbiologist is studying a specimen at a total magnification of 950x,what is the magnifying power of the objective lens if the ocular lens is 10x?

Accepted Answer

The answer of If a microbiologist is studying a specimen...

Question 20

Which of the following controls the amount of light entering the specimen?

Accepted Answer

The iris diaphragm controls the amount of light entering the specimen by regulating the size of the opening through which light passes. The objective lens is responsible for magnifying the specimen, the ocular lens further magnifies the image produced by the objective lens, the condenser focuses the light onto the specimen, and the body holds all the components together.

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

Which of the following magnifies the specimen to produce its real image?

Which type of microscope is the most widely used and shows cells against a bright background?

Magnification is achieved in a compound microscope through the initial magnification of the specimen by the _ lens.This image is then projected to the _ lens that will further magnify the specimen to form a virtual image received by the eye.

Which of the following characteristics refers to the microscope's ability to show two separate entities as separate and distinct?

A rod-shaped bacterium is measured as 0.3 micrometers ( $\mu$ m) in length using an ocular micrometer.Your instructor wants you to report the length in millimeters (mm) to test your understanding of metric conversions.What is the length of the organism in millimeters?

Which of the following magnifies the specimen to produce its virtual image?

The _____ of the microscope holds and allows selection of the objective lenses.

Which type of microscope shows cells against a bright background but also differentiates intracellular structures of unstained cells based on their varying densities?

Differential media results in which of the following growth characteristics?

Bacteria that require special growth factors and complex nutrients are termed

A microbiologist must culture a patient's feces for intestinal pathogens.Which of the following would likely be present in selective media for analyzing this fecal specimen?

An enveloped virus measures 0.02 micrometers ( $\mu$ m) in diameter.What is the diameter of this virus in nanometers (nm) ?

All of the following are diameters of cells that would be resolved in a microscope with a 0.2 µm limit of resolution except

A reducing media is used to culture

A microbiologist inoculates Staphylococcus aureus into a culture medium.Following incubation,both Staphylococcus aureus and Staphylococcus epidermidis are determined to be growing in this culture.What is the most likely explanation?

Newly inoculated cultures must be _____ at a specific temperature to encourage growth.

The type of microscope in which you would see brightly illuminated specimens against a black background is

For which bacterial genus does mannitol salt agar differentiate between species?

If a microbiologist is studying a specimen at a total magnification of 950x,what is the magnifying power of the objective lens if the ocular lens is 10x?

Which of the following controls the amount of light entering the specimen?

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

Which of the following magnifies the specimen to produce its real image?

Which type of microscope is the most widely used and shows cells against a bright background?

Magnification is achieved in a compound microscope through the initial magnification of the specimen by the _____ lens.This image is then projected to the _____ lens that will further magnify the specimen to form a virtual image received by the eye.

Which of the following characteristics refers to the microscope's ability to show two separate entities as separate and distinct?

A rod-shaped bacterium is measured as 0.3 micrometers ( μ\muμ m) in length using an ocular micrometer.Your instructor wants you to report the length in millimeters (mm) to test your understanding of metric conversions.What is the length of the organism in millimeters?

Which of the following magnifies the specimen to produce its virtual image?

The _____ of the microscope holds and allows selection of the objective lenses.

Which type of microscope shows cells against a bright background but also differentiates intracellular structures of unstained cells based on their varying densities?

Differential media results in which of the following growth characteristics?

Bacteria that require special growth factors and complex nutrients are termed

A microbiologist must culture a patient's feces for intestinal pathogens.Which of the following would likely be present in selective media for analyzing this fecal specimen?

An enveloped virus measures 0.02 micrometers ( μ\muμ m) in diameter.What is the diameter of this virus in nanometers (nm) ?

All of the following are diameters of cells that would be resolved in a microscope with a 0.2 µm limit of resolution except

A reducing media is used to culture

A microbiologist inoculates Staphylococcus aureus into a culture medium.Following incubation,both Staphylococcus aureus and Staphylococcus epidermidis are determined to be growing in this culture.What is the most likely explanation?

Newly inoculated cultures must be _____ at a specific temperature to encourage growth.

The type of microscope in which you would see brightly illuminated specimens against a black background is

For which bacterial genus does mannitol salt agar differentiate between species?

If a microbiologist is studying a specimen at a total magnification of 950x,what is the magnifying power of the objective lens if the ocular lens is 10x?

Which of the following controls the amount of light entering the specimen?

Magnification is achieved in a compound microscope through the initial magnification of the specimen by the _ lens.This image is then projected to the _ lens that will further magnify the specimen to form a virtual image received by the eye.

A rod-shaped bacterium is measured as 0.3 micrometers ( $\mu$ m) in length using an ocular micrometer.Your instructor wants you to report the length in millimeters (mm) to test your understanding of metric conversions.What is the length of the organism in millimeters?

An enveloped virus measures 0.02 micrometers ( $\mu$ m) in diameter.What is the diameter of this virus in nanometers (nm) ?