Unit 3 Lecture – Flashcards
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The five I's of studying microorganisms include all of the following except |
infection |
All of the following are examples of different types of microbiological media except |
petri dish |
The term that refers to the purposeful addition of microorganisms into a laboratory nutrient medium is |
inoculation |
Which of the following is essential for development of discrete, isolated colonies? |
solid medium |
| A pure culture contains only |
| one species of microorganisms |
Which of the following will result when 1% to 5% agar is added to nutrient broth, boiled and cooled? |
a solid medium |
| 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? |
| The culture is contaminated. |
| A microbiologist inoculates Staphylococcus epidermidis and Escherichia coli into a culture medium. Following incubation, only the E. coli grows in the culture. What is the most likely explanation? |
| The culture medium must be selective. |
| Which method often results in colonies developing down throughout the agar and some colonies on the surface? |
| pour plate |
| A common medium used for growing fastidious bacteria is |
| blood agar |
| A nutrient medium that has all of its chemical components identified and their precise concentrations known and reproducible would be termed |
| synthetic |
| A reducing medium contains |
| substances that remove oxygen. |
| Which type of medium is able to distinguish different species or types of microorganisms based on an observable change in the colonies or in the medium? |
| differential |
| A microbiologist decides to use a nutrient medium that contains thioglycollic acid. What type of microbe is she attempting to culture? |
| anaerobe |
For which bacterial genus is mannitol salt agar selective? |
Staphylococcus |
A microbiologist must culture a patient's feces for intestinal pathogens. Which of hte following would likely be present in selective media for analyzing this fecal specimen? |
bile salts |
Which of the following characteristics refers to the microscope's ability to show two separate entities as separate and distinct? |
resolving power |
Which of the following magnifies the specimen to produce the real image of the specimen? |
objective lens |
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 |
All of the following are diameters of cells that would be resolved in a microscope with a limit of resolution of 0.2um except |
0.1um |
| The wavelength of light used plus the numerical aperture governs |
resolution |
The type of microscope in which you would see brightly illuminated specimens against a black background is |
dark-field |
This microscope does not use light in forming the specimen image |
electron |
This microscope achieves the greatest resolution and highes magnification. |
electron |
This microscope shows cells against a bright background and also shows intracellular structures of unstained cells based on their varying densities |
phase-contrast |
This microscope is the most widely used and shows cells against a bright background |
bright-field |
All of the following pertain to the fluorescence microscope except it |
uses electron's to produce a specimen image |
Which is incorrect about chocolate agar? |
It has chocolate extract in it |
Which microscope bombards a whole, metal-coated specimen with electrons moving back and forth over it? |
Scanning electron |
The specimen preparation that is best for viewing cell motility is |
hanging drop |
The primary purpose of staining cells on a microscope slide is to |
add contrast in order to see them better |
The Gram stain, acid-fast stain and endospore stain have the following in common |
are differential stains |
Basic dyes are |
attracted to the acidic substances of bacterial cells |
A microbiologist makes a fixed smear of bacterial cells and stains them with Loeffler's methylene blue. All the cells appear blue under the oil lens. This is an example of |
simple staining |
Media that contains extracts from plants, animals, or yeast are |
complex |
Brain-heart infusion, trypticase soy agar (TSA) and nutrient agar are all examples of which type of media? |
nonsynthetic |
Bacteria that require special growth factors and complex organic substances are called |
fastidious |
A media is designed that allows only Strephylococci to grow. In addition, S. aureus colonies have a yellow halo around them and other staphlyococci appear white. This type of media is |
both selective and differential |
All of the following are examples of basic dyes except |
nigrosin |
Which type of media can be used to determine if a bacteria is motile? |
SIM |
All of the following are correct about agar except |
it is a source of nutrition for bacteria |
Which of the following media is useful for cultivating fungi? |
Sabouraud's agar |
| Which of the following puts the Five "I"s in their correct order? |
| inoculation, incubation, isolation, inspection, identification |
| Why is oil of immersion often used when viewing specimens under the microscope? |
| to increase the resolution |
| The procedure for culturing a microorganism requires the sue of a microscope |
| False |
| One colony typically develops from the growth of several parent bacterial cells. |
| False |
| Some microbes are not capable of growing on artificial media. |
| True |
| Mixed cultures are also referred to as contaminated cultures. |
| False |
| A medium that is gel-like has less agar in it compared to a solid medium. |
| True |
| A selective medium contains one or more substances that inhibit growth of certain microbes in order to facilitate the growth of other microbes. |
| True |
| A bacterial species that grows on blood agar but will not grow on trypticase soy agar is termed an anaerobe. |
False |
| Fixed smears of speciemns are required in order to perform the Gram stain and endospore stain on the specimens. |
True |
| The bending of light rays as they pass from one medium to another is called refraction. |
True |
| At the end of the Gram stain, gram positive bacteria will be seen as purple cells. |
| True |
| Scanning tunneling and atomic force microscopes are used to image the detailed structure of biological molecules. |
True |
| The type of bacteria that retain their initial stain and do not decolorize after washing with a lipid solvent such as alcohol |
Both gram positive and acid fast |
| The closest spacing between two points at which they can still be seen clearly as separate entities. |
resolution |
| Cells are caused to adhere to slides by the process called |
fixation |
Technique of staining the background of a specimen when a specimen resists taking up a stain |
Negative stain |
Dark-field microscopy is utilized in the diagnosis of the primary stage of this disease. |
syphilis |
Acid-fast organisms belonging to the genus Mycobacterium resist decolorization by acid-alcohol because of the high concentration of ____ in their cell walls. |
waxes |
In the electron microscope, a stream of ____ is employed as a source of illumination instead of visible light. |
electrons |
Culture media designed to favor the growth of specific microorganisms. |
selective media |
| The macroscopically visible growth of microorganisms on a solid culture media |
colony |
| Ideal solidifying agent employed in solid culture media to study microorganisms. |
agar |
| _____ technique is used to prevent the contamination of a pure culture of microorganism with extraneous microorganisms and to prevent human contact with potentially dangerous microorganisms. |
Aseptic |
| If the Gram's Iodine step were omitted in the Gram's procedure, what color would you expect Gram positive bacteria and Gram negative bacteria to stain? |
Gram+ = pink Gram - = pink |
| Culture media that allows you to separate even closely related groups of microorganisms. |
differential media |
| A microscope that has it usefulness based upon the differences of densities between cell components and their surroundings. |
phase-contrast microscope |
| Pure culture technique utilizing dilute suspensions of microorganisms which are added to melted and cooled agar. |
pour plate method |
| Culture media that contains various substances whose precise chemical composition are unknown. |
complex media |
| Which of the following microscopes would be appropriately used in a hospital Tuberculosis wards? |
fluorescent microscope |
| Methanol fixation is desired if |
the organisms are easily damaged by heat |
| A hanging drop slide preparation is useful for determining which of the following |
motility |
| Which of the following may be learned by performing a gram stain? |
morphology and which grouping it belongs to based on its cell wall
B & C both |
| Which type of plating technique allows you to enumerate the number of organisms in your culture? |
both pour and spread plating |
| What color would a gram negative bacteria appear when viewed iwth a microscope after the complete Gram staining procedure? |
red/pink |
| What kind of media contains dissolved or suspended particles that result from a boiling or soaking action (e.g. nutrient broth)? |
| infusion media |
| What type of media contains just one kind of sugar, such as monosaccharide or disaccharide, and is used to determine if the organisms can utilize the sugar or not? |
carbohydrate media |
| ____ is a type of microscope that is very useful for observing unstained living microorganisms |
Phase contrast |
| Which type of plating technique may be used for isolation only? |
streak |
| Which type of microscope produces the greatest magnification? |
scanning tunneling |
| An old culture would have a negative impact on which of the following? |
Both the gram stain and motility result would be negatively impacted. |
| What type of identification technique utilizes a piece of known DNA that may combine with only similar DNA and is a very specific identification method? |
DNA probe |
| In a ____ plate technique, the sample is added directly to liquid agar prior to hardening. |
pour |
| ____ are the type of microbes that prefer the moderate temperature range such as associated with the human body. |
mesophile |
Transfer of microbes: Inoculation
Stain used only to increase contrast: Simple stain
Only one microbe present: Pure culture
Unwanted microbes present: Contaminated culture
Procedure used to determine motility: Hanging drop technique
Stain used to identify Mycobacterium and Nocardia: Acid fast stain
Portion of the dye that imparts color: Chromophore
Primary stain in the gram stain procedure: Crystal Violet |
