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3.E: The Cell (Exercises)

  • Page ID
    27357
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    3.1: Spontaneous Generation

    The theory of spontaneous generation states that life arose from nonliving matter. It was a long-held belief dating back to Aristotle and the ancient Greeks. Experimentation by Francesco Redi in the 17th century presented the first significant evidence refuting spontaneous generation by showing that flies must have access to meat for maggots to develop on the meat. Louis Pasteur is credited with conclusively disproving the theory and proposed that “life only comes from life.”

    Multiple Choice

    Which of the following individuals argued in favor of the theory of spontaneous generation?

    1. Francesco Redi
    2. Louis Pasteur
    3. John Needham
    4. Lazzaro Spallanzani
    Answer

    C

    Which of the following individuals is credited for definitively refuting the theory of spontaneous generation using broth in swan-neck flask?

    1. Aristotle
    2. Jan Baptista van Helmont
    3. John Needham
    4. Louis Pasteur
    Answer

    D

    Which of the following experimented with raw meat, maggots, and flies in an attempt to disprove the theory of spontaneous generation.

    1. Aristotle
    2. Lazzaro Spallanzani
    3. Antonie van Leeuwenhoek
    4. Francesco Redi
    Answer

    D

    Fill in the Blank

    The assertion that “life only comes from life” was stated by Louis Pasteur in regard to his experiments that definitively refuted the theory of ___________.

    Answer

    spontaneous generation

    True/False

    Exposure to air is necessary for microbial growth.

    Answer

    False

    Short Answer

    Explain in your own words Pasteur’s swan-neck flask experiment.

    Explain why the experiments of Needham and Spallanzani yielded in different results even though they used similar methodologies.

    Critical Thinking

    What would the results of Pasteur’s swan-neck flask experiment have looked like if they supported the theory of spontaneous generation?

    3.2: Foundations of Modern Cell Theory

    Although cells were first observed in the 1660s by Robert Hooke, cell theory was not well accepted for another 200 years. The work of scientists such as Schleiden, Schwann, Remak, and Virchow contributed to its acceptance. Endosymbiotic theory states that mitochondria and chloroplasts, organelles found in many types of organisms, have their origins in bacteria. Significant structural and genetic information support this theory. The miasma theory was widely accepted until the 19th century.

    Multiple Choice

    Which of the following individuals did not contribute to the establishment of cell theory?

    1. Girolamo Fracastoro
    2. Matthias Schleiden
    3. Robert Remak
    4. Robert Hooke
    Answer

    A

    Whose proposal of the endosymbiotic theory of mitochondrial and chloroplast origin was ultimately accepted by the greater scientific community?

    1. Rudolf Virchow
    2. Ignaz Semmelweis
    3. Lynn Margulis
    4. Theodor Schwann
    Answer

    C

    Which of the following developed a set of postulates for determining whether a particular disease is caused by a particular pathogen?

    1. John Snow
    2. Robert Koch
    3. Joseph Lister
    4. Louis Pasteur
    Answer

    B

    Fill in the Blank

    John Snow is known as the Father of _____________.

    Answer

    epidemiology

    The ____________ theory states that disease may originate from proximity to decomposing matter and is not due to person-to-person contact.

    Answer

    miasma

    The scientist who first described cells was _____________.

    Answer

    Robert Hooke

    Short Answer

    How did the explanation of Virchow and Remak for the origin of cells differ from that of Schleiden and Schwann?

    What evidence exists that supports the endosymbiotic theory?

    What were the differences in mortality rates due to puerperal fever that Ignaz Semmelweis observed? How did he propose to reduce the occurrence of puerperal fever? Did it work?

    Critical Thinking

    Why are mitochondria and chloroplasts unable to multiply outside of a host cell?

    Why was the work of Snow so important in supporting the germ theory?

    3.3: Unique Characteristics of Prokaryotic Cells

    Prokaryotic cells differ from eukaryotic cells in that their genetic material is contained in a nucleoid rather than a membrane-bound nucleus. In addition, prokaryotic cells generally lack membrane-bound organelles. Prokaryotic cells of the same species typically share a similar cell morphology and cellular arrangement. Most prokaryotic cells have a cell wall that helps the organism maintain cellular morphology and protects it against changes in osmotic pressure.

    Multiple Choice

    Which of the following terms refers to a prokaryotic cell that is comma shaped?

    1. coccus
    2. coccobacilli
    3. vibrio
    4. spirillum
    Answer

    C

    Which bacterial structures are important for adherence to surfaces? (Select all that apply.)

    1. endospores
    2. cell walls
    3. fimbriae
    4. capsules
    5. flagella
    Answer

    C, D

    Which of the following cell wall components is unique to gram-negative cells?

    1. lipopolysaccharide
    2. teichoic acid
    3. mycolic acid
    4. peptidoglycan
    Answer

    A

    Which of the following terms refers to a bacterial cell having a single tuft of flagella at one end?

    1. monotrichous
    2. amphitrichous
    3. peritrichous
    4. lophotrichous
    Answer

    D

    Bacterial cell walls are primarily composed of which of the following?

    1. phospholipid
    2. protein
    3. carbohydrate
    4. peptidoglycan
    Answer

    D

    True/False

    Bacteria have 80S ribosomes each composed of a 60S large subunit and a 40S small subunit.

    Answer

    False

    Fill in the Blank

    Prokaryotic cells that are rod-shaped are called _____________.

    Answer

    bacilli

    The type of inclusion containing polymerized inorganic phosphate is called _____________.

    Answer

    volutin (or metachromatic granule)

    Short Answer

    What is the direction of water flow for a bacterial cell living in a hypotonic environment? How do cell walls help bacteria living in such environments?

    How do bacterial flagella respond to a chemical gradient of an attractant to move toward a higher concentration of the chemical?

    Label the parts of the prokaryotic cell.

    A diagram of a bacterial cell. The thick outer structure of the cell is not lableled. The next layer in (a thinner structure) is labeled E. A much thinner structure inside of that is labeled F. Inside of F is the main body of the cell. Small dots are labeled B. A long line forming a loop is labeled C. On the outside of the cell, short projections are labeled A and a long projection is labeled D.

    Critical Thinking

    Which of the following slides is a good example of staphylococci?

    A) A micrograph of rods in a cluster. B) a micrograph of individual rods. C) A micrograph of spheres in a chain. D) a micrograph of spheres in a cluster.

    (credit a: modification of work by U.S. Department of Agriculture; credit b: modification of work by Centers for Disease Control and Prevention; credit c: modification of work by NIAID)

    Provide some examples of bacterial structures that might be used as antibiotic targets and explain why.

    The causative agent of botulism, a deadly form of food poisoning, is an endospore-forming bacterium called Clostridium botulinim. Why might it be difficult to kill this bacterium in contaminated food?

    3.4: Unique Characteristics of Eukaryotic Cells

    Eukaryotic cells are defined by the presence of a nucleus containing the DNA genome and bound by a nuclear membrane (or nuclear envelope) composed of two lipid bilayers that regulate transport of materials into and out of the nucleus through nuclear pores. Eukaryotic cell morphologies vary greatly and may be maintained by various structures, including the cytoskeleton, the cell membrane, and/or the cell wall. The nucleolus in the nucleus of eukaryotic cells is the site of ribosomal synthesis.

    Multiple Choice

    Which of the following organelles is not part of the endomembrane system?

    1. endoplasmic reticulum
    2. Golgi apparatus
    3. lysosome
    4. peroxisome
    Answer

    D

    Which type of cytoskeletal fiber is important in the formation of the nuclear lamina?

    1. microfilaments
    2. intermediate filaments
    3. microtubules
    4. fibronectin
    Answer

    B

    Sugar groups may be added to proteins in which of the following?

    1. smooth endoplasmic reticulum
    2. rough endoplasmic reticulum
    3. Golgi apparatus
    4. lysosome
    Answer

    C

    Which of the following structures of a eukaryotic cell is not likely derived from endosymbiotic bacterium?

    1. mitochondrial DNA
    2. mitochondrial ribosomes
    3. inner membrane
    4. outer membrane
    Answer

    D

    Which type of nutrient uptake involves the engulfment of small dissolved molecules into vesicles?

    1. active transport
    2. pinocytosis
    3. receptor-mediated endocytosis
    4. facilitated diffusion
    Answer

    B

    Which of the following is not composed of microtubules?

    1. desmosomes
    2. centrioles
    3. eukaryotic flagella
    4. eukaryotic cilia
    Answer

    A

    True/False

    Mitochondria in eukaryotic cells contain ribosomes that are structurally similar to those found in prokaryotic cells.

    Answer

    True

    Fill in the Blank

    Peroxisomes typically produce _____________, a harsh chemical that helps break down molecules.

    Answer

    hydrogen peroxide

    Microfilaments are composed of _____________ monomers.

    Answer

    actin

    Short Answer

    What existing evidence supports the theory that mitochondria are of prokaryotic origin?

    Why do eukaryotic cells require an endomembrane system?

    Name at least two ways that prokaryotic flagella are different from eukaryotic flagella.

    Critical Thinking

    Label the lettered parts of this eukaryotic cell.

    Image of a cell. the outside line is labeled A. A long projection to the outside is labeled H. A large sphere in the cell has an outer line labeled B. A smaller sphere in the larger sphere is labeled C. Outside of this sphere but still inside the cell are folds of membranes with dots labeled F. Another set of folded membranes in a stack is labeld G; smaller spheres are coming off of these stacks. An oval structure with lines inside is labeld D and two small tubes are labeled E.

    How are peroxisomes more like mitochondria than like the membrane-bound organelles of the endomembrane system? How do they differ from mitochondria?

    Why must the functions of both lysosomes and peroxisomes be compartmentalized?


    3.E: The Cell (Exercises) is shared under a CC BY license and was authored, remixed, and/or curated by LibreTexts.

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