Assignment #3

Which of the following is NOT a component of bacterial flagella?
tubulin

Which of the following bacterial cell structures plays an important role in the creation of biofilms?
both fimbriae and glycocalyces

Cytoplasmic membranes of ________ are composed of phospholipids.
 bacteria and eukaryotes

If a eukaryotic cell suffers damage to its mitochondria, which of the following processes of life would be most immediately affected?
Energy Production

Bacteria of the genus Mycoplasma lack cell walls. What sort of environment do they require for survival?
 isotonic

Lipid A is a component of
lipopolysaccharides.

A bacterial cell possesses a glycocalyx. Which of the following is FALSE?
 It will be engulfed more quickly by defensive cells of the host.

Which of the following would NOT be found in the cytoplasm of a bacterial cell?
porins

Bacterial cell walls that are resistant to drying contain
waxes.

Which of the following organelles is responsible for producing most of the ATP in a eukaryotic cell?
mitochondrion

Which of the following have a periplasmic space?
Gram-negative bacteria only

Which of the following statements concerning pili is FALSE?
Pili are longer than fimbriae and flagella.

Which of the following statements about the endoplasmic reticulum (ER) is CORRECT?
The ER is a transport system within the cytoplasm.

Which of the following would contain teichoic acids?
a Gram-positive cell wall

The filament and basal body are associated with which of the following external structures found in some bacterial cell?
flagella

A bacterial cell is placed in distilled water. Which of the following will happen?
The cell will gain water.

Protein synthesis occurs in the
ribosome 

Which of the following molecules is shared by both Gram-positive and Gram-negative organisms?
N-acetylmuramic acid

Amoxicillin is an antibiotic that inhibits the formation of peptide cross-links. Amoxicillin, therefore, would most likely inhibit the growth of __________.
 both Gram-positive and Gram-negative organisms

Porins are present in ______________bacteria because, in these organisms, molecules entering the cell must pass through an extra layer of ___________.
Gram-negative; membrane

Which of the following chemical substances contributes to the unique characteristics of acid-fast bacteria?
mycolic acid

A bacterial cell moving toward light would be an example of
positive phototaxis.

A bacterial cell stains positive with the acid-fast stain. Which of the following is FALSE?
It has a cell wall that contains endotoxin.

Lipid-soluble molecules would be expected to cross the cytoplasmic membrane by which of the following processes?
 diffusion

The cells illustrated in the figure are in a(n) ________ environment.
hypotonic

Cell walls composed of polysaccharide are found in
archaea, bacteria, and eukaryotes.

Microscopy and Staining

A resolution of 1μm would be better than a resolution of 0.5 μm.
       False

Viruses are generally measured in
       nanometers.

Coating a specimen with a heavy metal is a step in preparing it for (phase/fluorescent/electron) microscopy.
      Electron

The process of immobilizing organisms on a glass slide through the application of either heat or chemicals is (staining/mordant/fixation).
       Fixation

The total magnification using a 10 ocular and a 100 objective would be (110/1000/10000) X. (Be sure your answer is a numeral.)
        1000

Why does immersion oil improve resolution?
        It increases numerical aperture and maintains a uniform light speed.

How are negative stains different from other types of stains?
        They stain the background, leaving the cells colorless.

Which of the following is an example of a dye used in a simple stain?
       Methylene blue

How does the malachite green stain enter an endospore?
       It is heated

Following an endospore stain, how does one distinguish endospores from vegetative cells?

Vegetative cells are pink, endospores are green.

What is the fundamental purpose of staining in light microscopy?

     To increase the contrast and visibility of the specimen

Why is a specimen smaller than 200 nm not visible with a light microscope?

      Anything smaller than 200 nm cannot interact with visible light.

What happens to the light rays when they hit the specimen?
     They are reflected, refracted, or absorbed by the specimen.

What is the role of the ocular lens?

    To recreate the image in the viewer’s eye

What is meant by light rays being divergent?

     It is spreading out

In a typical brightfield microscope (seen in the animation), at which point does magnification begin?

     The objective lens

You are shown a micrograph from a light microscope in which the specimens appear bright compared to the background. The micrograph is probably from a(n) ________ microscope.

     dark-field

Which of the following is an incorrect pairing?

    numerical aperture; curved glass

In Gram staining, ethanol-acetone is used as a

     decolorizing agent

The microscope preferred for viewing living specimens is the ________ microscope.

     phase-contrast

Which of the following microscopes produces the highest resolution images?

     atomic force

A primary purpose for the use of stains in microscopy is the increase the (magnification/brightness/contrast) of a specimen.

     contrast

If a microbiology lab student left the safranin out of the Gram stain procedure, what would be the result?

     Gram-positive cells would be purple and Gram-negative cells would be colorless.

The Gram stain can be used to distinguish bacteria based on the structure of their cell walls.

     true

In the Gram stain procedure, iodine serves as a

     mordant.

In a compound microscope, the lens that directs light through the specimen is the (ocular/condenser/objective) lens.

      condenser

A measurement of a microbe is reported as 1 × 10^-6 m, also known as

     micrometers (μm).

Introduction

Which of the following statements concerning Koch's postulates is false?

       The suspected pathogen may not be present in all cases of the disease being studied.

Which of the following was NOT an aspect of Pasteur's experiments to disprove spontaneous generation?

      The flasks he used were sealed with corks.

Microorganisms characterized by the absence of a nucleus are called

      prokaryotes

Whose search for chemicals that would kill microbes without harming humans was the foundation for chemotherapy?

       Ehrlich

The microbes commonly known as ________ are single-celled eukaryotes that are generally motile.

      protozoa

Which of the following question largely stimulated the research of microbes during what is known as the Golden Age of Microbiology?

What causes disease, and is spontaneous generation of microbes possible?

Antoni van Leeuwenhoek was the first person in history to

        view microorganisms and record these observations.

What is the correct order for the application of Koch's postulates?
I. Inoculate suspect agent into test subject and observe that subject develops disease of interest.
II. Isolate and culture suspect agent in the laboratory.
III. Find suspect agent is every case of disease of interest but not in healthy hosts.
IV. Recover and isolate suspect agent from test subject.

           III, II, I, IV

Which of the following is NOT a characteristic of viruses?

        They are visible with a light microscope.

Identification of bacteria in the laboratory usually begins with the ________ for placement in one of two large groups of bacteria.

        Gram stain

Which of the following individuals pioneered the use of chemicals to reduce the incidence of infections during surgery?

     Lister

Which of the following statements about fungi is FALSE?

      Fungi are photosynthetic.

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