Chapter 2 - History of Microbiology Flashcards
Upon which two basic methods is microbiology founded?
- Microscopy
- Pure culture technique
Why is microscopy important to the field of microbiology?
Microbes are very small and require microscopes to be seen
Why is pure culture technique important to the field of microscopy?
Because each individual type of microbe must be separated from others in order for study
What do we mean by resolution?
The ability of a microscope to differentiate between two objects
Who discovered microbes
Leeuwenhoek
How did Leeuwenhoek discover microbes? In other words, what type of microscope did he use?
A simple microscope with a lens of unusually high quality
Why did simple microscopes offer better quality images than compound microscopes in the 18th century?
Although compound microscopes offer many advantages, they must be made of exceptionally high-quality lens because any distoritions in the first lens are magnified by the second. Simple microscopes therefore offered higher quality images because of their lesser distortion
In what century did Leeuwenhoek discover microbes?
The 16th century
What was the principal innovation that lead to the improvement of the compound microscope?
The replacement of each of the lenses in the compound microscope with a set of lenses that were designed to correct a particular type of distortion
The final step in the evolution of the compound microscope was the development of the ________________, a device that proces an even illumination of the specimen.
Condenser
Advances in ________________ during the 19th century led to improved ____________________________.
Optics
Microscopes
Advances in ___________ ____________________ in the 20th century were largely confined to improved methods of enhancing ___________________.
Light microscopy
Contrast
What approach did scientists use to enhance contrast in the 19th and early 20th century?
Staining
What was the primary disadvantage of using staining to contrast microbial specimens?
Normally the stains used killed the cells
What two innovations in the 20th century led to greater improvements in contrast?
- Phase-contrast microscopy
- Darkfield microscopy
_________________ microscopy makes objects much darker than they would otherwise be, whereas _________________ microscopy shows them as bright objects against a black background.
Phase-constrast microscopy
Darkfield microscopy
What was the most significant advance in microscopy in the 20th century?
The electron microscope
The limit of resolution for an electron microscope is at least a ______________________ times better than the light microscope.
1000 times
Light microscopes cannot visualize objects less than ____ _______. Electron microscopes can theoretically visualize the smallest of objects, but practical issues limit visualization to a _______________ or less.
0.1 µm
1 nm
What did Leeuwenhoek call the microbes moving around in pond water?
Animalcules
For most of human history, people believed that life came from the three processes. What were they?
- Sexual reproduction
- Asexual reproduction
- Spontaneous generation
What is the idea of spontaneous generation?
The supposed production of living organisms from nonliving matter, as inferred from the apparent appearance of life in some supposedly sterile environments.
Who is credited with presenting the concept of spontaneous generation?
Aristotle
Aristotle proposed that life arose from nonliving material if the material contained _______ ______.
Vital heat





