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