1.3.E: The Cell (Exercises)
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?
- Francesco Redi
- Louis Pasteur
- John Needham
- Lazzaro Spallanzani
- Answer
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C
Which of the following individuals is credited for definitively refuting the theory of spontaneous generation using broth in swan-neck flask?
- Aristotle
- Jan Baptista van Helmont
- John Needham
- Louis Pasteur
- Answer
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D
Which of the following experimented with raw meat, maggots, and flies in an attempt to disprove the theory of spontaneous generation.
- Aristotle
- Lazzaro Spallanzani
- Antonie van Leeuwenhoek
- Francesco Redi
- Answer
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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
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spontaneous generation
True/False
Exposure to air is necessary for microbial growth.
- Answer
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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?
- Girolamo Fracastoro
- Matthias Schleiden
- Robert Remak
- Robert Hooke
- Answer
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A
Whose proposal of the endosymbiotic theory of mitochondrial and chloroplast origin was ultimately accepted by the greater scientific community?
- Rudolf Virchow
- Ignaz Semmelweis
- Lynn Margulis
- Theodor Schwann
- Answer
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C
Which of the following developed a set of postulates for determining whether a particular disease is caused by a particular pathogen?
- John Snow
- Robert Koch
- Joseph Lister
- Louis Pasteur
- Answer
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B
Fill in the Blank
John Snow is known as the Father of _____________.
- Answer
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epidemiology
The ____________ theory states that disease may originate from proximity to decomposing matter and is not due to person-to-person contact.
- Answer
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miasma
The scientist who first described cells was _____________.
- Answer
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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?