Ch. 2 Homework
Select the methods below that enable the isolation of bacteria.
-Quadrant streak plate -Loop dilution -Use of selective media -Spread plate
All of the following are diameters of cells that would be resolved in a microscope with a 0.2 µm limit of resolution except _____.
0.1 µm
The patient's urine culture growth was observed on a medium containing growth factors and complex nutrients. Which term best describes this type of medium?
Enriched medium
What is the most universal diagnostic staining technique used for bacterial identification and classification?
Gram stain
A rod-shaped bacterium is measured as 0.3 micrometers (μm) 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?
0.0003 mm
A human squamous epithelial cell measures 75 µm in diameter. The size of this cell represented in millimeters (mm) would be _____ mm.
0.075
A virus that is 150 nm (nanometers) in diameter would be _______ μm (micrometers) in diameter.
0.150 μm
Viruses are commonly grown in/on _______.
animal cells or tissues
A reducing media is used to culture ______.
anaerobic organisms
Basic dyes are ______.
attracted to the negatively charged acidic substances of bacterial cells
In the case, the patient is treated with antibiotics for her UTI. This is because Escherichia coli is a _________.
bacterium
A common medium used for growing fastidious bacteria is ______.
blood agar
Rod-shaped bacteria _______.
can be either gram-positive or gram-negative
To identify the microbe, one step of inspection involves examination for colony growth characteristics. All the following are macroscopically observed characteristics except _______.
cell shape
The differential stage of the Gram stain is the application of _______.
ethanol
Newly inoculated cultures must be _____ at a specific temperature to encourage growth.
incubated
The Five I's of studying microorganisms include all of the following except _____.
infection
In a _______ stain, the dye stains the background, forming a silhouette around the unstained organism.
negative
All of the following are examples of different types of microbiological media except _____.
petri dish
Resolution differs from contrast in microscopy in that ______.
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
Label the image to review the components of a compound light microscope.
(Down the left side, then across the bottom, then up the right side of image) -Ocular -Nosepiece -Objective lens -Mechanical stage -Diaphragm -Light source -Base -Stage adjustment -Fine focus -Coarse focus -Arm
Label the image to test your understanding of common measurements encountered in microbiology and the size range of microorganisms.
(From top to bottom, left side, then right side) -1mm -100µm -10µm -1µm -200nm -100nm -10nm -1nm -0.1nm -Range of human eye -Range of light microscope -Range of electron microscope
Please label the cultures below to demonstrate your understanding of pure, mixed, and contaminated cultures.
(Left to right) -Contaminated Culture -Pure Culture -Mixed Culture
Move the terms into the correct empty boxes to complete the concept map.
(Left to right) -Contrast -Resolution -Numerical aperture -Magnification
Label the figure to demonstrate your understanding of selective and differential media.
(Left to right) -General-Purpose Medium (different species look similar) -Differential Medium -General-Purpose Medium (many different species grow) -Selective Medium
Label these general laboratory techniques carried out by microbiologists, also known as the "Five I's of Microbiology."
(Left to right) -Inoculation -Incubation -Isolation -Inspection -Identification
Match the step in the microbial culturing process to its appropriate description.
(Top to bottom) -Inoculation -Incubation -Isolation -Inspection -Identification
Label the missing categories in the chart to assess your knowledge of media classification.
(Top to bottom) -Physical State -Functional Type -Chemical Composition
Select the elements necessary for good microscopy.
-Adequate magnification -Contrast -Resolution
Choose the three basic ways that media are classified.
-Chemical composition -Purpose -Physical state
Match the media with their general intended purpose or category.
-Enriched: Thayer Martin (chocolate) agar -Selective and differential: MacConkey agar -General-purpose: Nutrient agar -Anaerobic: Reducing media -Differential: Urea broth
Select the correct answers that identify the Five I's of culturing microorganisms.
-Identification -Inspection -Inoculation -Isolation -Incubation
Review the five I's of microbiology laboratory techniques by completing each sentence.
-Inoculation involves placing a sample into a container of fresh medium. -Multiplication of an organism in a culture is promoted by incubation. -Pour plating, streak plating, and spread plating are isolation methods for separating individual microbes from each other. -Inspection involves the observation of macroscopic and microscopic characteristics of microbes in samples. -Biochemical, immunological, and genetic testing assist the microbiologist in information gathering so that a final identification can be made.
Drag the images to their corresponding class to test your understanding of isolation methods.
-Loop Dilution: (1 image) 3 plates -Streak Plate: (2 images) 4 plates One red plate with hands -Spread Plate: (1 image) 2 plates with lids open
Match the statement to the term that it most accurately describes to test your understanding of the elements of good microscopy.
-Magnification: The apparent increase in size of an image -Contrast: Ability to be distinguished from the surroundings -Resolution: The ability to distinguish between two separate structures that are very close to one another
After Gram's iodine is added, what color do the cells appear under a light microscope?
All cells appear purple
Diagnosis of infections in a hospitalized person is often accomplished via ______. Check all that apply.
-microscopy -culture of samples from the patient
Differential media results in which of the following growth characteristics?
All of the choices are correct.
The patient's culture was introduced to a liquid medium. In addition to liquid, which of the following are physical types of media?
All of the choices are correct.
A bacterial cell that measures 2.5 μm (micrometers) would measure _____ nm (nanometers).
2,500 nm
An enveloped virus measures 0.02 micrometers (μm) in diameter. What is the diameter of this virus in nanometers (nm)?
20 nm
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?
95x
Which of the following will result when 1% to 5% agar is added to nutrient broth, boiled, and cooled?
A solid medium
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?
Acid-fast stain
Drag the images or descriptions to their corresponding class to test your understanding of various types of microscopes and the images that they produce.
Bright-Field Microscope: -Common light microscope used in the general microbiology lab course Dark-Field Microscope: -Black image with tan mark Scanning Electron Microscope: -Light green and little bit of light blue image Fluorescent Microscope: -Bright green photo with bright blue dots Phase-Contrast Microscope: -Grey with tan mark Confocal Microscope: -Provides a three-dimensional image when a computer cimbines multiple optical sections of a specimen stained with fluorescent dye Transmission Electron Microscope: -Black and white photo
What general type of stain is used to separate types of bacteria based on their cellular structures?
Differential
The Gram stain, which employs different colored dyes to analyze bacterial cell wall structure, is an example of which type of staining method?
Differential stain
Which type of microscope achieves the greatest resolution and highest magnification?
Electron
A fastidious organism must be grown on/in what type of medium?
Enriched medium
A mixed culture is a culture with two microbes, whereas a contaminated culture is a culture with three or more microbes. (T/F)
False
All bacteria can be classified as either gram-positive or gram-negative. (T/F)
False
At the end of the Gram stain, gram-positive bacteria will be seen as red/pink cells. (T/F)
False
Bacteria are larger than human cells. (T/F)
False
Bacteria are only visible with an electron microscope. (T/F)
False
Females consuming cranberry juice exhibited the greatest incidence of UTIs as compared to the group with no treatment. (T/F)
False
It is normal to have a relatively large amount of bacteria in a clean catch sample. (T/F)
False
One colony typically develops from the growth of several parent bacterial cells. (T/F)
False
The presence of flagella can be determined by a Gram stain. (T/F)
False
The procedures for culturing a microorganism require the use of a microscope. (T/F)
False
The thinner peptidoglycan layer of gram-positive bacteria allows the crystal-violet-iodine complex to leave the cell. (T/F)
False
The RN anticipates the specimen will be prepared in the lab and examined for identification. What is the term describing any procedure that applies dye to a specimen smear?
Staining
For which bacterial genus does mannitol salt agar differentiate between species?
Staphylococcus
The results of the first urine sample came back after 48 hours. Which one of the four required this length of time?
Incubation
The lab introduces the sample into a medium with the appropriate nutrients to sustain growth. What term describes this process?
Inoculation
Which of the following is not a benefit of agar as a solid medium?
Is digested by most microbes
The culture is stored at the proper growth temperature for three days. Upon assessment, visible growth is noted. In order to separate a single microbe, a sample is transferred onto another medium to allow for colony growth. What term describes this process?
Isolation
E. coli is usually an inhabitant of the human body without causing negative effects. Why did it cause infection in this patient?
It entered a different part of the body
The patient's culture is found to have growth of gram-negative bacteria. What unique component of the outer membrane of gram-negative bacteria acts as an endotoxin, causing symptoms of shock?
Lipopolysaccharide
Which of the following is not an inoculating tool?
Petri dish
While describing sample processing, the RN refers to the process of inoculation. He explains that the sample is introduced to a nutrient-rich substance capable of sustaining microbe growth. What is the name of this sterile substance that allows for microorganism multiplication?
Medium
If the Gram's iodine step was skipped in Gram stain procedure, what color would the cells likely be when viewed under the microscope?
Most cells would appear red/pink
Why must fresh cells be used when performing a Gram stain?
Old cells may not Gram-stain properly
Based upon the data collected, which juice do you hypothesize contains the greatest amount of tannins?
Pomegranate
Which method often results in colonies developing down throughout the agar along with some colonies on the surface?
Pour plate
When a urine sample reaches the laboratory, what is the first technique used to determine if a urinary tract infection exists?
Sample is observed microscopically
Which type of microscope bombards a whole, metal-coated specimen with electrons moving back and forth over it?
Scanning electron
Choose the description that best fits a medium that has been designed to support the growth of MRSA (methicillin-resistant Staphylococcus aureus) while inhibiting all species and strains of other bacteria.
Selective
Drag the descriptions to the correct type of medium to test your understanding of various selective and differential media.
Selective Media: -Enterococcus faecalis broth: Sodium azide allows for the growth of fecal enterococci -MacConkey Agar: Bile and crystal violet allow for the growth of gram-negative enterics -Lowenstein-Jensen: Malachite green allows for the growth of Mycobacterium -Sabouraud's Agar: Acidic media which allows for the growth of fungi Differential Media: -Blood Agar: Demonstrates hemolysis of Streptococcus species -Mannitol Salt Agar: Phenol red allows for identification of Staphylococcal species -Triple-sugar Iron Agar: Identification of hydrogen sulfide producing bacteria -MacConkey Agar: Neutral red allows for identification of lactose fermenting bacteria
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?
Selective medium
Drag the images to their corresponding class to test your understanding of various types of microbiological stains.
Simple Stain: (1 image) -Blue dots image -Use of one colored dye Special Stain: (2 images) -Dark tan with light tan dots -Pinkish with red looking dots Differential Stain: (3 images) -Endospore Stain (image) -Acid-fast Stain (image) -Split of two images in one
The physician orders cultures to be drawn from the patient's invasive intravenous lines. What term describes the technique the RN must utilize during specimen collection to ensure a proper culture?
Sterile
What type of isolation technique is most effective for the majority of applications?
Streak plate
In the absence of immersion oil when using the 100x objective lens, some light would be lost to scatter resulting in a blurry image. (T/F)
True
Why are urinary tract infections more common in women?
The female urethra is shorter than the male urethra
E. coli is an intestinal organism, and Staphylococcus epidermidis resides on the skin. What do you hypothesize will occur when both are inoculated onto mannitol salt agar?
The salt inhibits the growth of E. coli, which is not a halophile; the S. epidermidis will grow.
What do the Gram stain, acid-fast stain, and endospore stain have in common?
The outcome is based on cell differences.
A nutrient medium that has all of its chemical components identified, and their precise concentrations known and reproducible, would be termed ________.
a chemically defined media
Reducing the intensity of light using the iris diaphragm or staining a specimen can improve _________.
contrast
In this study, the group that did not receive treatment is called the ______ group; this data is necessary to compare results of the various treatments reliably.
control
The type of microscope in which you would see brightly illuminated specimens against a black background is _____.
dark field
All of the following pertain to the fluorescence microscope except ______.
it uses electrons to produce a specimen image
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.
objective; ocular
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) _____.
pure culture
When ethanol is applied correctly, gram-positive cells appear _______ and gram-negative cells appear ________.
purple; colorless
The term used to describe a cluster of spherical bacteria is _______.
staphylococci
