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15.3: Chapter 3 exercises

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  • 3.1: The Properties of Light

    Which of the following has the highest energy?

    1. light with a long wavelength
    2. light with an intermediate wavelength
    3. light with a short wavelength
    4. It is impossible to tell from the information given.

    You place a specimen under the microscope and notice that parts of the specimen begin to emit light immediately. These materials can be described as _____________.

    1. fluorescent
    2. phosphorescent
    3. transparent
    4. opaque

    Fill in the Blank

    When you see light bend as it moves from air into water, you are observing _________.

    3.1.1: Peering into the Invisible World

    Short Answer

    Why is Antonie van Leeuwenhoek’s work much better known than that of Zaccharias Janssen?

    Why did the cork cells observed by Robert Hooke appear to be empty, as opposed to being full of other structures?

    Multiple Choice

    Who is the probable inventor of the compound microscope?

    1. Girolamo Fracastoro
    2. Zaccharias Janssen
    3. Antonie van Leeuwenhoek
    4. Robert Hooke

    Fill in the Blank

    A microscope that uses multiple lenses is called a _________ microscope.

    3.1.2: Instruments of Microscopy

    Which type of microscope is especially useful for viewing thick structures such as biofilms?

    1. a transmission electron microscope
    2. a scanning electron microscopes
    3. a phase-contrast microscope
    4. a confocal scanning laser microscope
    5. an atomic force microscope

    Which type of microscope would be the best choice for viewing very small surface structures of a cell?

    1. a transmission electron microscope
    2. a scanning electron microscope
    3. a brightfield microscope
    4. a darkfield microscope
    5. a phase-contrast microscope

    What type of microscope uses a cone of light so that light only hits the specimen indirectly, producing a darker image on a brighter background?

    1. a transmission electron microscope
    2. a scanning electron microscope
    3. a brightfield microscope
    4. a darkfield microscope
    5. a phase-contrast microscope

    Fill in the Blank

    Chromophores that absorb and then emit light are called __________.

    What is the total magnification of a specimen that is being viewed with a standard ocular lens and a 40⨯ objective lens?

    Short Answer

    What is the function of the condenser in a brightfield microscope?

    Label each component of the brightfield microscope.

    Critical Thinking

    When focusing a light microscope, why is it best to adjust the focus using the coarse focusing knob before using the fine focusing knob?

    3.2: Staining Microscopic Specimens

    Multiple Choice

    What mordant is used in Gram staining?

    1. crystal violet
    2. safranin
    3. acid-alcohol
    4. iodine

    What is one difference between specimen preparation for a transmission electron microscope (TEM) and preparation for a scanning electron microscope (SEM)?

    1. Only the TEM specimen requires sputter coating.
    2. Only the SEM specimen requires sputter-coating.
    3. Only the TEM specimen must be dehydrated.
    4. Only the SEM specimen must be dehydrated.

    Fill in the Blank

    Ziehl-Neelsen staining, a type of _______ staining, is diagnostic for Mycobacterium tuberculosis.

    The _______ is used to differentiate bacterial cells based on the components of their cell walls.

    Short Answer

    How could you identify whether a particular bacterial sample contained specimens with mycolic acid-rich cell walls?

    Critical Thinking

    You use the Gram staining procedure to stain an L-form bacterium (a bacterium that lacks a cell wall). What color will the bacterium be after the staining procedure is finished?

    3.3 Review Questions

    The smallest unit of biological structure that meets the functional requirements of “living” is the ________.

    1. organ
    2. organelle
    3. cell
    4. macromolecule

    Viruses are not considered living because they ________.

    1. are not made of cells
    2. lack cell nuclei
    3. do not contain DNA or RNA
    4. cannot reproduce

    Free response

    Select two items that biologists agree are necessary in order to consider an organism “alive.” For each, give an example of a non-living object that otherwise fits the definition of “alive.”

    You go for a long walk on a hot day. Give an example of a way in which homeostasis keeps your body healthy.

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