Ch 1 Textbook

Question 1

Microbiology is defined not only by the organisms it studies but also by what?

Answer 1

The tools used to study them

Question 2

A distinct feature of microbiology is that microbiologists often remove microorganisms from their normal habitats and culture them isolated from other microbes; this is called a ____ or _____ culture.

Answer 2

pure or axenic culture

Question 3

________ led to the discovery of microorganisms

Answer 3

Microscopy

Question 4

The earliest microscopic observations of organisms appear to have been made between 1625 and 1630 on ____ and _____ by the Italian Francesco Stelluti (1577–1652), using a microscope probably supplied by Galileo (1564–1642).

Answer 4

bees and weevils

Question 5

What is the importance of “Micrographia” by Robert Hooke (1665)?

Answer 5

It not only included detailed drawings of the fungus Mucor, but it also included important instructions on how to build microscopes.

Question 6

Who was the first to document their sightings of bacteria and protists?

Answer 6

Antony van Leeuwenhoek, who likely used one of the prototypes in Micrographia, and could magnify 50-300x.

Question 7

After the invention of the microscope, microbiology stagnated for 200 years until the creation of what?

Answer 7

Techniques for isolating and culturing microbes in

the laboratory

Question 8

The creation of culture-based methods for studying microorganisms coincided with what?

Answer 8

Scientists grappling with the conflict over the
theory of spontaneous generation. This conflict and the subsequent studies on the role played by microorganisms in causing disease ultimately led to what is now called the golden age of microbiology.

Question 9

Define spontaneous generation

Answer 9

The theory that living organisms could develop from nonliving matter

Question 10

Who was the first to argue against spontaneous generation, and what experiment did he conduct to support his theory?

Answer 10

Francesco Redi (1626–1697), who carried out a series of experiments on decaying meat and its ability to produce maggots spontaneously. 
Using covered and uncovered containers of meat, Redi clearly demonstrated that the generation of maggots by decaying meat resulted from the presence of fly eggs, and meat did not spontaneously generate maggots, as previously believed.

Question 11

What extracts were the forerunners of the culture media still used today in many microbiology laboratories?

Answer 11

Boiled hay and meat extracts

Question 12

Many argued that the presence of organisms on boiled meat and hay extracts proved the theory of spontaneous generation; who disproved this and when?

Answer 12

John Needham (1713–1781) suggested that the organic
matter in these extracts contained a vital force that could confer the properties of life on nonliving matter.

Question 13

What was the role of Italian priest and naturalist Lazzaro Spallanzani (1729–1799) in microbiology?

Answer 13

Lazzaro Spallanzani (1729–1799) sealed glass
flasks that contained water and seeds and then placed the flasks in boiling water for about 45 minutes. He found that no growth took place as long as the flasks remained sealed. 
He proposed that air carried germs to the culture medium but also commented that external air might be required for growth of animals already in the medium.

Question 14

Felix Pouchet (1800–1872) claimed in 1859 to have carried out experiments conclusively proving that microbial growth could occur without air contamination, which provoked what scientist to finally settle the debate?

Answer 14

Louis Pasteur (1822–1895)

Question 15

How did Louis Pasteur (1822–1895) settle the matter of spontaneous generation?

Answer 15

He first filtered air through cotton and found that objects resembling plant spores had been trapped. If a piece of the cotton was placed in sterile medium after air had been filtered through it, microbial growth occurred. Next he placed nutrient solutions in flasks, heated their necks in a flame, and drew them out into a variety of curves. The swan-neck flasks that he produced in this way had necks open to the atmosphere. Pasteur then boiled the solutions for a few minutes and allowed them to cool. No growth took place even though the contents of the flasks were exposed to the air. Pasteur pointed out that growth did not occur because dust and germs had been trapped on the walls of the curved necks. If the necks were broken, growth commenced immediately.
Pasteur had not only resolved the controversy by 1861 but also had shown how to keep solutions sterile.

Question 16

Support for the germ theory of disease began when?

Answer 16

In the early 1800s

Question 17

Give 3 examples of early scientists who helped prove germ theory

Answer 17

1) Agostino Bassi (1773–1856) demonstrated in
1835 that a silkworm disease was due to a fungal infection. He also suggested that many diseases were due to microbial infections.
2) In 1845 M. J. Berkeley (1803–1889) proved that the great potato blight of Ireland was caused by a water mold (then thought to be a fungus)
3) In 1853 Heinrich de Bary (1831–1888) showed that smut and rust fungi caused cereal crop diseases

Question 18

What contributions of Pasteur also contributed to the ethanol and alcohol industries?

Answer 18

The discovery of yeast (helped the ethanol industry understand fermentation) and the development of pasteurization (helped the wine industry understand diseased wines)

Question 19

Who developed a system of antiseptic surgery designed to prevent microorganisms from entering wounds?

Answer 19

English surgeon Joseph Lister (1827–1912). He heat sterilized instruments and used phenol on surgical dressings and at times sprayed it over the surgical
area

Question 20

The first direct demonstration that bacteria cause disease came from the study of what and by whom?

Answer 20

The study of anthrax by the German physician Robert Koch (1843–1910)

Question 21

Describe the development of Koch’s postulates

Answer 21

-Koch injected healthy mice with material from diseased animals, and the mice became ill. After
transferring anthrax by inoculation through a series of 20 mice, he incubated a piece of spleen containing the anthrax bacillus in beef serum. The bacteria grew, reproduced, and produced endospores. When isolated bacteria or their spores were injected into healthy mice, anthrax developed. -His criteria for proving the causal relationship between a microorganism and a specific disease are known as Koch’s postulates.

Question 22

How did the creation of pure cultures come about?

Answer 22

Koch used gelatin, but bacteria didn’t grow well, so one of his student’s wives suggested agar as a nutrient/ medium, which is still used today. His laboratory also created Petri dishes as well as nutrient broth.

Question 23

Who first theorized the existence of viruses, and what led him to theorize this?

Answer 23

Charles Chamberland (1851–1908), one of
Pasteur’s associates, constructed a porcelain bacterial filter in 1884. Dimitri Ivanowski (1864–1920) and Martinus Beijerinck (1851–1931) used the filter to study tobacco mosaic disease. They found that plant extracts and sap from diseased plants were infectious, even after being filtered with Chamberland’s filter. 
Because the infectious agent passed through a filter that was designed to trap bacterial cells, they reasoned that the agent must be something smaller than a bacterium. Beijerinck proposed that
the agent was a “filterable virus.”

Question 24

Who was the first to perform an immunological study, and what was it?

Answer 24

Pasteur and Pierre Roux (1853–1933)
discovered that incubating the cultures for long intervals between transfers caused the cultures to lose their ability to cause disease. These cultures were said to be attenuated. When chickens were injected with attenuated cultures, they not only remained healthy but also were able to resist the disease when exposed to virulent cultures. Pasteur called the attenuated culture a vaccine in honor of Edward Jenner (1749–1823) because, many years earlier, Jenner had used material from cowpox lesions to protect people against smallpox

Question 25

What did the Russian microbiologist Sergei Winogradsky (1856–1953) do for field of soil microbiology?

Answer 25

1) The discovery that soil bacteria could oxidize iron, sulfur, and ammonia to obtain
energy and that many of these bacteria could incorporate CO2 into organic matter much as photosynthetic organisms do.
2) He also isolated anaerobic nitrogen-fixing soil bacteria and studied the decomposition of cellulose
3) He developed enrichment culture techniques and selective media, which have been of great importance in microbiology

Question 26

Describe the differences between basic and applied microbiology

Answer 26

The basic aspects are concerned with the biology of microorganisms themselves.
The applied aspects are concerned with practical problems such as disease, water and wastewater treatment, food spoilage and food production, and industrial uses of microbes

Question 27

What some argue to be the ‘second golden age of microbiology’ has come about in recent years due to the increased use of what?

Answer 27

Molecular and genomic methods to study microbes and their interactions with other organisms

Question 28

Define a genome

Answer 28

All the genetic information that organism contains

Question 29

What were the 3 first most important developments in genomic methods for studying microbes?

Answer 29

1) The discovery that DNA could be split with enzymes (now known as restrictive enzymes) (1960s)
2) The generation of recombinant DNA molecules (1972)
3) The development of methods to determine the sequence of nucleotides in DNA. (1970s)

Question 30

What is the first step in genomic analysis?

Answer 30

Genome sequencing

Question 31

Genomic analysis with the use of computers is known as what?

Answer 31

Bioinformatics

Question 32

The use of DNA sequencing and related methods on microbes in the environment is called what?

Answer 32

Metagenomics

Question 33

What has metagenomics done for the field of microbiology?

Answer 33

It has allowed microbiologists to
determine which organisms are present in an environment and what they are doing without first having to culture them; this is critical because only 1-2% are easily cultured

Question 34

Describe medical microbiology

Answer 34

It deals with diseases of humans
and animals. Medical microbiologists identify the agents causing infectious diseases and help plan measures for their control and elimination. Frequently they are involved in tracking down new, unidentified pathogens (like COVID)

Question 35

Describe microbial ecology

Answer 35

Defined as the study of the ecological
role of microorganisms rather than their role in disease.
Today, a variety of approaches, including non-culture-based techniques, are used to describe the vast diversity of microbes in terms of their
morphology, physiology, and relationships with organisms and the components of their habitats. The importance of microbes in global and local cycling of carbon, nitrogen, and sulfur is well documented

Question 36

Describe agricultural microbiology

Answer 36

Agricultural microbiology is concerned with the impact of microorganisms on agriculture.
Microbes such as nitrogen-fixing bacteria play critical roles in the nitrogen cycle and affect soil fertility. Other microbes live in the digestive tracts of ruminants such as cattle and break down the plant materials these animals ingest. There are also
plant and animal pathogens that have significant economic impact if not controlled.

Question 37

Describe industrial microbiology

Answer 37

• Defined as the use of microorganisms to make products such as vaccines, steroids, alcohols and other solvents, vitamins, amino acids, and enzymes
• Industrial microbiologists identify or genetically engineer microbes of use to industrial processes, medicine, agriculture, and other commercial enterprises
• Industrial microbiology developed in large part from Pasteur’s work on alcoholic fermentations

Question 38

Microbial physiologists study what?

Answer 38

Many aspects of the biology of microorganisms, including their metabolic capabilities, the synthesis of antibiotics and toxins, the ways in which microorganisms survive harsh environmental conditions, and the effects of chemical and physical agents on microbial growth and survival