Microbiology CH.3

Choose all of the following that play a role in microscopy.

-wavelength of light
-magnification
-resolution
-contrast

What term is used to refer to the fact that the image formed is larger than the original specimen? We say that the specimen has been

magnified

As I look into the microscope I notice that the image formed is difficult to see clearly. In scientific jargon, I would say "this microscope has poor _________________".

resolution

Through different staining techniques it is possible to increase the ________________ on the slide making it easier to view details of the specimen.

contrast

Which of the following would represent the lowest wavelength radiation from the listed choices?

ultra violet

Which of the following types of microscopes uses UV radiation when producing an image to be viewed?

-light microscope
-fluorescent microscope

As the wavelength of light decreases, the resolution of the microscope increases.

true

Which of the following microscopes would allow us to observe living things and their internal structures without killing them with dyes or heat fixation?

phase contrast

Leeuwenhoek observed many microbes with his early compound bright field light microscope.

false

This type of microscope has a series of lenses for magnification and is the one that we would utilize in our labs?

compound bright field

What would the total magnification of a specimen be if a new objective was created for a compound light microscope consisting of an ocular lens and an objective lens with a magnification of 150x? (Answer format: Example 700x)

1500 X

Which of the following represents why using immersion oil is beneficial in increasing the resolution of the microscope under the oil immersion objective?

it allows for light to travel towards the objective lens without bending too much in order to increase the resolution

Which of the following microscopes would you use with pale specimens and find that the contrast is increased due to a dark background and a lightened specimen? This microscope is used on Live and Unstained specimens.

dark-field

Which of the following microscopes is the most widely used, results in the image of the specimen being darker than the surrounding field (Bright Background), for live specimens, and / or for preserved stained specimens?

bright-field

Which of the following microscopes would utilize antibodies with fluorescent dyes to increase contrast on the specimen when it releases energy in the form of light?

fluorescent

Which of the following microscopes would use a laser beam to scan the specimen and would integrate images to allow for multiple depths or planes.

confocal

Electron microscopes have the ability to image a specimen with greater detail than a fluorescent microscope.

true

Which of the following microscopes did we say could help us visualize DNA and Enzymes with pretty remarkable detail?

atomic force microscopes

I am attempting to stain a bacterium that has a negatively charged cell surface. Which of the following dyes should I use?

basic

Acidic dyes tend to bind to alkaline structures.

true

Basic dyes are generally positively charged and Acidic dyes are generally negatively charged.

true

Choose all of the following dyes that would generally be used to determine the morphology of a cell or a group of cells. (Simple Stains)

-crystal violet
-safranin
-methylene blue

I am trying to determine the species found on a pure culture in lab. Which of the following stains would I use first to begin narrowing down what it could be?

gram stain

Choose all of the following stains that would be commonly used when distinguishing between different cells, chemicals, or structures.

-gram stain
-acid fast stain
-endospore stain
-histological stain

Which of the following stains would be helpful in determining if a bacterium has the ability to survive harsh environments due to a special structure it contains?

endospore stain

Which of the following types of stains would stain the background and can be used to reveal bacterial capsules.

negative stain

Many times the stains for transmission electron microscopy contain heavy metals.

true

taxonomy

consists of classification, nomenclature, and identification.

Wavelength

the distance between two corresponding parts of a wave of radiation

What is an advantage of using dark-field microscopy instead of bright-field microscopy?

the contrast is better due to the dark background which allows better visualization of detail

What type of microscopy uses a beam of electrons to create a three dimensional image of the surfaces of specimens.

scanning electron

It is an advantage to use a microscope that does not require the use of stains because this allows for the viewing of the specimen while it is still alive.

true

Which of the following did we mention as a necessary first step before a specimen can be stained?

smear it on the slide and heat it in a flame

James goes to the doctor with an extremely sore throat. It is confirmed that he has strep throat caused by the bacterium Streptococcus pyogenes. Streptococcus pyogenes is a Gram Positive, coccus shaped bacterium. After a gram stain which of the following represent what this organism will appear as under the microscope?

purple and spherical shaped

Which of the following taxonomic categories can fit the greatest number of species under it?

domain

Which of the following represents the correct form for binomial nomenclature?

Escherichia coli (Italicized)

Which of the following represents the main method for which Woese assigned organisms into domains?

ribosomal RNA nucleotide sequences (rRNA)

One method for identification of microorganisms is to place viruses on a bacterial lawn and look for the formation of plaques. This method is known as _______________ typing.

phage

You are tasked with identifying two different bacteria from a mixed culture. These bacteria are similar in morphology and therefore do not appear to be different when stained. Which of the following would we perform to get better insight into the classification of these organisms?

biochemical testing

Which of the following scientists developed the taxonomic system?

Linnaeus

Which of the following is a test that could be done to identify organisms by using antibody-antigen interactions?

serological tests

Dichotomous

key is a series of paired statements where only one of two choices applies to any particular organism.

Once an inoculate has been placed onto an agar plate it would then be ________________. This refers to placing it into a chamber that is set at a specific temperature for optimal growth of the organisms being cultured.

incubated

Which kingdom discussed in class would contain no nucleus and a cell with peptidoglycan?

eubacteria

Which kingdom discussed is a eukaryotic kingdom made up of organisms that obtain their food from other organisms, have cell walls, and contains molds and yeasts?

fungi

Yeast fall into the kingdom plantae, are unicellular, and reproduce asexually by budding.

false

Protozoa

single celled eukaryotes that are similar to animals in their nutrient needs and celluar structure

Algae are many times photosynthetic organisms and fall in the domain Eukarya.

true

You are in the lab and just isolated E. coli from a mixed culture. You then transfer E. coli to a new slant for growth and extended keeping. After one week, you decide it is time to transfer your E. coli to a new slant. After incubating the new inoculum for 24 hours, you decide to stain it just to ensure you are working with a pure culture. You find both E. coli and S. epidermidis in your stain. The culture is likely ___________________. This refers to the fact that the culture is now impure due to the presence of a microbe that should not be there.

contaminated

In order to get the best resolution possible with a light microscope, you would want:

short wavelengths of light

What is the name for a tiny amount of a sample that is introduced to some nutrient Agar or Broth in order to create a culture?

inoculum

The 3 physical forms of media that we can see in the microbiology lab include: Solid Media, Semi-Solid Media, and Liquid Media.

true

Some organisms do not grow on any microbiological medium. These types of organisms are referred to as

nonculturable

What are the six i's?

-inoculation
-isolation
-incubation
-inspection
-information gathering
-identification

Solid media is essential for the development of discrete, isolated colonies.

true

A culture that only contains one species of organism is termed a

pure culture

A culture that contains multiple species of organisms is termed a

mixed culture

You inoculate a medium with both Gram + and Gram - organisms. After 48 hours you find that only the Gram - organisms grew on the medium. This type of media is likely

selective

________ agar is commonly used for growing fastidious bacteria.

chocolate

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

Which of the following properties of a microscope did we refer to as its ability to make out objects CLEARLY? This allows for us to clearly see two objects on a microscope slide as two separate & distinct objects rather than just one.

resolving power

Which of the following parts of a microscope are used to magnify and create a REAL image?

objective lens

Your lab partner tells you that they are viewing their Gram stain with a total magnification of 1,000x. Based on the fact that you know the ocular lens magnifies by 10x, what magnification is the objective lens that they are using to view their Gram stain?

100x

Based on the equation discussed in class, the factors that influence the Resolution or Resolving Power of a microscope include:

-numerical aperture
-wavelength of light

Based on our equation for Resolving Power (Limit of Resolution) which of the following would need to increase to obtain better resolution?

numerical aperture

Based on our equation for Resolving Power (Limit of Resolution) which of the following would need to decrease to obtain better resolution?

wavelength of light

Choose all of the following that are considered Light Microscopes?

-bright field microscope
-dark field microscope
-fluorescent microscope
-confocal microscope
-phase contrast microscopes

Which of the following microscopes would provide the best RESOLUTION and highest MAGNIFICATION?

electron microscope

Chocolate agar is only made of natural cocoa providing it with its rich color and nutrients for the growth of fastidious organisms.

false