1
Q
What is normal microbiota?
A
Microbes that live stably in and on the human body and can indefinitely colonize the body as benign normal microbiota.
2
Q
What is transient microbiota?
A
Microbes that are only a fleeting member of the body’s community.
3
Q
What are pathogenic species?
A
Disease-causing species.
4
Q
Approximately how many body cells does an adult human have?
A
About 30 trillion body cells.
5
Q
Approximately how many bacterial cells does an adult human harbor?
A
About 40 trillion bacterial cells.
6
Q
What is the human microbiome (or microbiota)?
A
Microbes that live stably in and on the human body.
7
Q
How do humans depend on the microbiome?
A
Humans depend on these microbes to maintain good health.
8
Q
How do bacteria in the intestines aid the human body?
A
They aid digestion and synthesize some vitamins that our bodies require, including B vitamins for metabolism and vitamin K for blood clotting.
9
Q
How do microbes help protect against disease-causing species?
A
They prevent the growth of pathogenic (disease-causing) species that might otherwise take up residence.
10
Q
What role do microbes play in the immune system?
A
They seem to have a role in training our immune system to know which foreign invaders to attack and which to leave alone.
11
Q
When do humans begin acquiring microbes?
A
Even before birth, our bodies begin to be populated with bacteria.
12
Q
What types of microbes do newborns acquire?
A
Viruses, fungi, and bacteria.
13
Q
What factors influence where microbes can colonize the body?
A
Temperature, pH, and the presence or absence of chemical compounds.
14
Q
What are some destructive actions of microbes?
A
Microorganisms are associated with infections and inconveniences such as spoiled food.
15
Q
What are some beneficial actions of microbes?
A
The majority help maintain the balance of life in our environment. Marine and freshwater microorganisms form the basis of the food chain in oceans, lakes, and rivers. Soil microbes break down wastes and incorporate nitrogen gas from the air into organic compounds, recycling chemical elements among soil, water, living organisms, and air. Certain microbes play important roles in photosynthesis, a food- and oxygen-generating process critical to life on Earth. Microorganisms are used in the synthesis of vitamins, organic acids, enzymes, alcohols, and many drugs. Microbes are used in food production such as vinegar, sauerkraut, pickles, soy sauce, cheese, yogurt, bread, and alcoholic beverages.
16
Q
What percentage of all the cells in the human body are bacterial cells?
A
An adult human is composed of about 30 trillion body cells and harbors another 40 trillion bacterial cells.
17
Q
How do microbes negatively affect our lives?
A
Microorganisms are associated with infections and inconveniences such as spoiled food.
18
Q
How do microbes affect environmental balance?
A
The majority of microorganisms help maintain the balance of life in our environment.
19
Q
How do microbes affect food chains in aquatic environments?
A
Marine and freshwater microorganisms form the basis of the food chain in oceans, lakes, and rivers.
20
Q
How do soil microbes affect the environment?
A
Soil microbes break down wastes and incorporate nitrogen gas from the air into organic compounds, thereby recycling chemical elements among soil, water, living organisms, and air.
21
Q
How do microbes contribute to photosynthesis?
A
Certain microbes play important roles in photosynthesis, a food- and oxygen-generating process that is critical to life on Earth.
22
Q
How are microbes used in commercial and industrial applications?
A
Microorganisms are used in the synthesis of vitamins, organic acids, enzymes, alcohols, and many drugs.
23
Q
How are microbes used in food production?
A
The food industry uses microbes to produce vinegar, sauerkraut, pickles, soy sauce, cheese, yogurt, bread, and alcoholic beverages.
24
Q
How do microbes affect human health through the microbiome?
A
Humans depend on microbes that live stably in and on the body to maintain good health.
25
How do intestinal microbes benefit the human body?
Bacteria in the intestines aid digestion and synthesize vitamins required by the body, including B vitamins for metabolism and vitamin K for blood clotting.
26
How do microbes protect against disease?
Microbes prevent the growth of pathogenic (disease-causing) species that might otherwise take up residence and help train the immune system to know which foreign invaders to attack.
27
normal microbiota
Microorganisms that are normally found in and on the human body.
28
transient microbiota
Microorganisms that are present in or on the body for a short time.
29
pathogenic species
Microorganisms that cause disease.
30
normal microbiota
Microbes that live stably in and on the human body as part of its community and can indefinitely colonize the body.
31
transient microbiota
Microbes that are only fleeting members of the body’s community and do not permanently colonize the body.
32
pathogenic species
Disease-causing species that can take up residence in the body if not prevented by normal microbiota.
33
Describe some destructive actions of microbes.
Microbes can cause infections and spoil food.
34
Describe some beneficial actions of microbes.
Microbes help maintain the balance of life in the environment, form the basis of food chains in oceans, lakes, and rivers, break down wastes, recycle chemical elements, incorporate nitrogen gas into organic compounds, and play important roles in photosynthesis.
35
What percentage of all the cells in the human body are bacterial cells?
An adult human has about 30 trillion body cells and harbors about 40 trillion bacterial cells.
36
How do microbes affect food chains and ecosystems?
Marine and freshwater microorganisms form the basis of the food chain in oceans, lakes, and rivers.
37
How do microbes contribute to nutrient cycling?
Soil microbes break down wastes and recycle chemical elements among soil, water, living organisms, and air.
38
How do microbes affect oxygen and food production?
Certain microbes play important roles in photosynthesis, a food- and oxygen-generating process critical to life on Earth.
39
How do microbes affect human health?
Microbes in the human body aid digestion, synthesize vitamins such as B vitamins and vitamin K, prevent the growth of pathogenic species, and help train the immune system.
40
What type of cells are bacteria?
Bacteria are single-celled (unicellular) organisms.
41
Are bacteria prokaryotic or eukaryotic?
Bacteria are prokaryotes.
42
Why are bacteria classified as prokaryotes?
Their genetic material is not enclosed in a special nuclear membrane.
43
What is the bacterial cell wall largely composed of?
A protein–carbohydrate complex called peptidoglycan.
44
How do bacteria reproduce?
By dividing into two equal cells in a process called binary fission.
45
How do most bacteria obtain nutrients?
By using organic chemicals derived from dead or living organisms.
46
How can some bacteria manufacture their own food?
By photosynthesis or by using inorganic substances.
47
How do many bacteria move?
By using moving appendages called flagella.
48
What are the most common bacterial shapes?
Bacillus (rod-shaped), coccus (spherical or ovoid), and spiral (curved or corkscrew).
49
What type of cells are archaea?
Archaea are prokaryotic cells.
50
How do archaeal cell walls differ from bacterial cell walls?
If present, archaeal cell walls lack peptidoglycan.
51
Where are archaea often found?
In extreme environments.
52
What are the three main groups of archaea?
Methanogens, extreme halophiles, and extreme thermophiles.
53
What do methanogens produce?
Methane as a waste product from respiration.
54
Where do extreme halophiles live?
In extremely salty environments.
55
Where do extreme thermophiles live?
In hot sulfurous water, such as hot springs.
56
Are archaea known to cause disease in humans?
No, archaea are not known to cause disease in humans.
57
Are fungi prokaryotic or eukaryotic?
Fungi are eukaryotes.
58
What defines fungi as eukaryotic organisms?
Their cells have a distinct nucleus surrounded by a nuclear membrane.
59
Can fungi be unicellular or multicellular?
Yes, fungi may be unicellular or multicellular.
60
What unicellular fungi are called?
Yeasts.
61
What multicellular fungi include?
Molds and mushrooms.
62
Can fungi carry out photosynthesis?
No, fungi cannot carry out photosynthesis.
63
What are fungal cell walls primarily composed of?
Chitin.
64
What are mycelia?
Visible masses formed by molds.
65
What structures make up mycelia?
Long filaments called hyphae.
66
How do fungi obtain nourishment?
By absorbing organic material from their environment.
67
How do fungi reproduce?
Sexually or asexually.
68
What type of organisms are protozoa?
Unicellular eukaryotic microbes.
69
How do protozoa move?
By pseudopods, flagella, or cilia.
70
What are pseudopods?
Extensions of cytoplasm used for movement (false feet).
71
How do protozoa obtain nutrients?
By absorbing or ingesting organic compounds.
72
How do protozoa live in the environment?
As free entities or as parasites.
73
Are any protozoa photosynthetic?
Yes, some protozoa (such as Euglena) are photosynthetic.
74
How do protozoa reproduce?
Sexually or asexually.
75
What type of organisms are algae?
Photosynthetic eukaryotes.
76
Are algae unicellular or multicellular?
Many algae are unicellular.
77
What are algal cell walls often composed of?
Cellulose.
78
Where are algae found?
Freshwater, saltwater, soil, and in association with plants.
79
What do algae require for food production and growth?
Light, water, and carbon dioxide.
80
What do algae produce as a result of photosynthesis?
Oxygen and carbohydrates.
81
Why are algae important to nature?
They play an important role in the balance of nature.
82
Are viruses cells?
No, viruses are acellular.
83
What genetic material do viruses contain?
Either DNA or RNA.
84
What surrounds the viral genetic material?
A protein coat, sometimes enclosed by a lipid envelope.
85
Can viruses reproduce independently?
No, they must use the cellular machinery of other organisms.
86
When are viruses considered living?
Only when they multiply within host cells.
87
Why are viruses considered nonliving outside a host?
They are inert outside living hosts.
88
Are multicellular animal parasites microorganisms?
No, but they are of medical importance.
89
What type of organisms are animal parasites?
Eukaryotes.
90
What are the two major groups of parasitic worms?
Flatworms and roundworms.
91
What are flatworms and roundworms collectively called?
Helminths.
92
Why are helminths sometimes considered in microbiology?
During some life stages, they are microscopic.
93
What is nomenclature in biology?
The system of naming organisms.
94
Who established the system of nomenclature used today, and when?
Carolus Linnaeus in 1735.
95
Why are scientific names Latinized?
Because Latin was the language traditionally used by scholars.
96
How many names are assigned to each organism in scientific nomenclature?
Two names.
97
What is the genus in a scientific name?
The first name of an organism; it is always capitalized.
98
What is the specific epithet?
The second name (species name) that follows the genus; it is not capitalized.
99
How is an organism properly referred to using scientific nomenclature?
By both the genus and the specific epithet together.
100
How should scientific names be written in text?
Both the genus and specific epithet are underlined or italicized.
101
How can a scientific name be abbreviated after it has been written once?
By using the initial of the genus followed by the specific epithet.
102
What kinds of information can scientific names describe?
They can describe an organism, honor a researcher, or identify the habitat of a species.
103
In Staphylococcus aureus, what does Staphylo- describe?
The clustered arrangement of the cells.
104
In Staphylococcus aureus, what does -coccus indicate?
That the cells are shaped like spheres.
105
What does the specific epithet aureus mean?
Latin for golden, referring to the color of many colonies of the bacterium.
106
What is the genus of Escherichia coli named after?
A physician, Theodor Escherich.
107
What does the specific epithet coli indicate?
That E. coli live in the colon, or large intestine.
108
How do you distinguish a genus from a specific epithet in scientific nomenclature?
The genus is the first name of an organism and is always capitalized; the specific epithet follows the genus, is not capitalized, and together with the genus identifies the organism.
109
What are the three domains?
1. Bacteria – Cell walls contain a protein–carbohydrate complex called peptidoglycan.
2. Archaea – Cell walls, if present, lack peptidoglycan.
3. Eukarya – Includes:
Protists (slime molds, protozoa, and algae)
Fungi (unicellular yeasts, multicellular molds, and mushrooms)
Plants (mosses, ferns, conifers, and flowering plants)
Animals (sponges, worms, insects, and vertebrates)
110
How can we define a microorganism (microbe)?
A microorganism can be defined using the mnemonic MICRO.
111
What does M stand for in the MICRO definition of microorganisms?
Microscopic — microorganisms are too small to be seen with the unaided eye and usually require a microscope.
112
What does I stand for in the MICRO definition of microorganisms?
Inconspicuous / found almost everywhere — microorganisms are found almost everywhere in the environment.
113
What does C stand for in the MICRO definition of microorganisms?
Cellular organization — most microorganisms are cellular; viruses are acellular.
114
What does R stand for in the MICRO definition of microorganisms?
Reproduce — living microorganisms can reproduce as self-sufficient units; viruses reproduce only inside host cells.
115
What does O stand for in the MICRO definition of microorganisms?
Other forms of life are affected — microorganisms affect human life and the balance of nature in beneficial and destructive ways.
116
Which characteristics are used to define microorganisms?
They are microscopic, found almost everywhere, have cellular organization (or are acellular in the case of viruses), can reproduce, and affect other forms of life.
117
What do microorganisms allow us to do?
- prevent disease
- develop aseptic techniques to prevent contamination and spread of disease
- prevent food spoilage
118
What is a prokaryote?
A prokaryote is a cell that lacks membrane-enclosed organelles.
119
Do prokaryotic cells have a nucleus?
No. Prokaryotes have a nucleoid region containing DNA, not a true nucleus.
120
What cellular components are found in all bacteria according to this slide?
Cytoplasm, ribosomes, plasma membrane, and nucleoid containing DNA.
121
Do most bacteria have a cell wall?
Yes. Almost all bacteria have cell walls.
122
What is the function of the plasma membrane in prokaryotes?
It surrounds the cytoplasm and separates the cell from its environment.
123
What are ribosomes responsible for in prokaryotic cells?
Protein synthesis.
124
What is the nucleoid?
A region in the prokaryotic cell that contains DNA.
125
What is a plasmid?
A small, circular piece of DNA found in some prokaryotes, separate from the nucleoid DNA.
126
What is the function of flagella?
Movement of the bacterial cell.
127
What are fimbriae and pili used for?
Attachment to surfaces or other cells.
128
What is a capsule, and do all bacteria have one?
A protective outer layer; not all bacteria have a capsule.
129
Do all bacteria have the same structures?
No. Not all bacteria have all the structures shown on the diagram.
130
What is the key concept of prokaryotic cells?
Prokaryotic cells lack membrane-enclosed organelles, have ribosomes, cytoplasm, a plasma membrane, a nucleoid, and most have cell walls.
131
What is a eukaryote?
A eukaryote is a cell that contains membrane-enclosed organelles, including a true nucleus.
132
What is the defining feature that distinguishes eukaryotes from prokaryotes?
The presence of a membrane-bound nucleus and membrane-enclosed organelles.
133
Where is DNA found in a eukaryotic cell?
Inside the nucleus.
134
What is the function of the nucleus?
It contains the cell’s DNA and controls cellular activities.
135
What is the nucleolus?
A structure inside the nucleus involved in ribosome production.
136
What is the function of mitochondria?
Energy production for the cell.
137
What is the role of the endoplasmic reticulum (ER)?
Rough ER: protein synthesis
Smooth ER: lipid synthesis and other metabolic functions
138
What is the Golgi complex responsible for?
Modifying, packaging, and transporting proteins.
139
What are ribosomes, and are they membrane-bound?
Ribosomes synthesize proteins and are not membrane-bound (even in eukaryotes).
140
What is the plasma membrane?
The outer boundary that controls what enters and leaves the cell.
141
What is the cytoplasm?
The fluid interior of the cell where organelles are suspended.
142
Which structures are found in plant cells but not animal cells (from this slide)?
Cell wall, chloroplasts, large vacuole.
143
What is the function of chloroplasts?
Photosynthesis.
144
What structure provides extra support in plant cells?
The cell wall.
145
Which structures are highlighted in animal cells on this slide?
Centrioles, lysosomes, flagellum (not all animal cells have a flagellum).
146
Do eukaryotes have membrane-enclosed organelles?
Yes.
147
Do prokaryotes have membrane-enclosed organelles?
No.
148
Which types of organisms are eukaryotic?
Protists, fungi, plants, and animals.
149
What are sporangia?
Structures in fungi that produce and contain spores.
150
What is the function of sporangia in fungi?
Spore production for reproduction and spread.
151
Are sporangia found in bacteria or fungi?
Fungi.
152
On a fungal image, what does a round structure at the tip of a stalk often represent?
A sporangium.
153
What do spores allow fungi to do?
Reproduce and spread to new environments.
154
What does the label “food particle” mean on a protozoa image?
A particle of food (such as bacteria or organic matter) that the protozoan is ingesting.
155
How do protozoa capture a food particle?
By extending a pseudopod to surround and engulf it.
156
Is a food particle a structure of the protozoan itself?
No — it is something the protozoan is eating.
157
What does the presence of a food particle demonstrate about protozoa?
They are heterotrophic (they obtain nutrients by consuming other material).
158
Which structure is labeled on protozoa images to show movement and feeding?
Pseudopod.
159
Why were Robert Hooke’s observations important to microbiology?
Hooke used an early microscope to observe and describe microscopic structures, helping establish the use of microscopy in studying living organisms.
160
Why were Antonie van Leeuwenhoek’s observations important to microbiology?
Van Leeuwenhoek was the first to observe and describe living microorganisms (“animalcules”), revealing the existence of microscopic life.
161
What is spontaneous generation?
Spontaneous generation is the hypothesis that life can arise spontaneously from nonliving matter.
162
What is biogenesis?
Biogenesis is the concept that living organisms arise only from preexisting life.
163
How did Pasteur’s work support biogenesis over spontaneous generation?
Pasteur demonstrated that microorganisms come from other microorganisms in the air and do not arise spontaneously from nonliving matter.
164
What contribution did John Needham make to microbiology?
Needham supported spontaneous generation after observing microbial growth in boiled broths.
165
What contribution did Lazzaro Spallanzani make to microbiology?
Spallanzani showed that boiling broth longer and sealing containers prevented microbial growth, arguing against spontaneous generation.
166
What contribution did Rudolf Virchow make to microbiology?
Virchow supported biogenesis with the concept that living cells arise only from preexisting cells.
167
What contribution did Louis Pasteur make to microbiology?
Pasteur conclusively disproved spontaneous generation and demonstrated that microorganisms are responsible for fermentation and spoilage.
168
How did Pasteur’s work influence Joseph Lister?
Pasteur’s work led Lister to apply germ theory to surgery, resulting in aseptic surgical techniques that reduced infections.
169
How did Pasteur’s work influence Robert Koch?
Pasteur’s findings encouraged Koch to link specific microorganisms to specific diseases.
170
What are Koch’s postulates?
Koch’s postulates are a sequence of experimental steps used to directly link a specific microorganism to a specific disease.
171
Why are Koch’s postulates important?
They provided scientific proof that specific microorganisms cause specific diseases.
172
What was the importance of Edward Jenner’s work?
Jenner demonstrated that inoculation with cowpox provided immunity to smallpox, leading to the development of vaccination.
173
What was Paul Ehrlich’s contribution to microbiology?
Ehrlich proposed the idea of a “magic bullet” and developed the first successful chemotherapeutic agent, salvarsan.
174
What was Alexander Fleming’s contribution to microbiology?
Fleming discovered penicillin, the first antibiotic, produced by the fungus Penicillium.
175
What is bacteriology?
Bacteriology is the study of bacteria.
176
What is mycology?
Mycology is the study of fungi.
177
What is parasitology?
Parasitology is the study of protozoa and parasitic worms.
178
What is immunology?
Immunology is the study of immunity and the immune system.
179
What is virology?
Virology is the study of viruses.
180
What is microbial genetics?
Microbial genetics studies how microorganisms inherit traits.
181
What is molecular biology?
Molecular biology examines how genetic information is carried in DNA and expressed.
182
What is genomics?
Genomics is the study of all of an organism’s genes and their functions.
183
Why are these fields important to microbiology?
They allow scientists to understand gene function, classify microorganisms, study evolution, and develop medical and biotechnological applications.
184
What is cell theory?
Cell theory states that all living organisms are composed of cells and that cells arise only from preexisting cells, supporting the concept of biogenesis.
185
What did Pasteur demonstrate about food spoilage?
Pasteur demonstrated that microbes are responsible for food spoilage.
186
Why was Pasteur’s work important for understanding disease?
Pasteur’s work led researchers to the connection between microbes and disease.
187
What practical techniques were developed based on Pasteur’s experiments and observations?
His experiments and observations provided the basis of aseptic techniques.
188
What is the purpose of aseptic techniques?
Aseptic techniques are used to prevent microbial contamination.
189
How did Pasteur’s experiments impact microbiology and medicine?
They showed that microbes cause food spoilage, linked microbes to disease, and provided the basis for aseptic techniques used to prevent microbial contamination.
190
What evidence supported spontaneous generation?
The appearance of life in nonliving materials, such as microorganisms appearing in nonliving solutions, was taken as evidence that life arose spontaneously.
191
How was spontaneous generation disproved?
Pasteur’s work provided proof of biogenesis, showing that microorganisms do not originate from nonliving materials, but instead come from microorganisms already present in the air or fluids.
192
summarize germ theory of disease
The germ theory of disease states that microorganisms can cause disease, based on discoveries showing that microorganisms are responsible for specific diseases rather than disease arising from punishment, demons, or other nonbiological causes.
193
importance of Koch’s postulates
Koch’s postulates provided a sequence of experimental steps used to directly link a specific microorganism to a specific disease, establishing proof that particular microbes cause particular diseases.
194
significance of Jenner’s discovery
Jenner’s discovery demonstrated that vaccination could provide immunity to disease, showing that exposure to a related, milder disease (cowpox) could protect against a deadly disease (smallpox), forming the basis of vaccination and immunity.
195
Ehrlich’s “magic bullet”
Ehrlich’s “magic bullet” was the idea of using a chemical substance that could destroy pathogenic microorganisms without harming the infected animal or human, forming the basis of chemotherapy.
196
bacteriology
the study of bacteria
197
mycology
the study of fungi
198
parasitology
the study of protozoa and parasitic worms
199
immunology
the study of immunity
200
virology
the study of viruses
201
Differentiate microbial genetics, molecular biology, and genomics.
Microbial genetics studies the mechanisms by which microorganisms inherit traits.
Molecular biology looks at how genetic information is carried in molecules of DNA.
Genomics is the study of all of an organism’s genes, allowing scientists to classify microorganisms based on genetic relationships and study gene function and evolution.
202
What did Pasteur’s work demonstrate about spontaneous generation?
That microorganisms do not arise spontaneously from nonliving matter.
203
What theory did Pasteur’s experiments support?
Biogenesis — living organisms arise from other living organisms.
204
How did Pasteur explain “spontaneous” growth seen in nonliving solutions?
It was caused by microorganisms already present in the air or fluids, not mystical forces.
205
What is fermentation according to Pasteur?
A process caused by microorganisms, not chemical reactions alone.
206
What is pasteurization?
The use of heat to reduce microbial growth and prevent food spoilage.
207
What are aseptic techniques?
Procedures that prevent contamination by unwanted microorganisms.
208
Why are aseptic techniques important?
They are now standard practice in laboratories and medical procedures to prevent infection.
209
What major idea did Koch help establish?
The germ theory of disease — specific microbes cause specific diseases.
210
What disease did Koch prove was caused by a specific microorganism?
Anthrax, caused by Bacillus anthracis.
211
What are Koch’s postulates?
A set of experimental steps used to link a specific microorganism to a specific disease.
212
Why are Koch’s postulates important?
They provided a scientific method to prove that microbes cause disease.
213
What laboratory advance did Koch develop?
Pure culture techniques to grow and study microorganisms individually.
214
What was Jenner’s key discovery?
Exposure to cowpox provided immunity to smallpox.
215
What was the significance of Jenner’s discovery?
It led to the first vaccine.
216
Why was Jenner’s work important to microbiology?
It laid the foundation for vaccination and immunology.
217
What is vaccination based on, according to the textbook?
Using avirulent or related microorganisms to stimulate immunity.
218
What did Louis Pasteur do?
1822 - 1895
Demonstrated that life did not arise spontaneously from nonliving matter
219
What theory was Pasteur testing with the swan-neck flask experiment?
Spontaneous generation — the idea that life arises from nonliving matter.
220
What theory did Pasteur’s experiment support?
Biogenesis — microorganisms come from other microorganisms.
221
What did Pasteur place into the long-necked flask?
Beef broth.
222
Why did Pasteur boil the broth?
To kill any microorganisms already present.
223
What was the purpose of bending the flask neck into an S-shape?
To prevent microorganisms from entering while still allowing air in.
224
After boiling and cooling, what happened to the broth?
No microorganisms appeared, even after long periods.
225
What does the lack of microbial growth show?
Microorganisms do not arise spontaneously in nonliving solutions.
226
Where did microorganisms come from, according to Pasteur?
From microorganisms already present in the air, liquids, or solids.
227
Why is the swan-neck important instead of a sealed flask?
It shows air alone does not cause microbial growth.
228
What happened when microbes were allowed to enter the broth?
Microorganisms grew in the broth.
229
What major concept did this experiment help establish in microbiology?
The connection between microbes, contamination, and spoilage.
230
How did this experiment contribute to aseptic techniques?
It showed contamination comes from external microorganisms, leading to procedures that prevent microbial entry.
231
What key concept is emphasized in the diagram’s box?
Microbes cause food spoilage
Pasteur’s work linked microbes to disease
His experiments formed the basis of aseptic techniques
232
In Pasteur’s swan-neck flask experiment, why did no microorganisms appear in the broth?
Because microorganisms were prevented from entering the flask.
233
Why is “air was absent” an incorrect explanation for Pasteur’s results?
Air was present, but microorganisms were trapped in the bend of the flask.
234
Why is “life cannot exist in broth” incorrect?
Microorganisms did grow when contamination was allowed.
235
What key conclusion should you choose on an MC exam?
Microbial growth requires contamination by pre-existing microorganisms, not air alone.
236
What was the purpose of heating (boiling) the infusion in Pasteur’s experiment?
To kill any microorganisms already present in the infusion.
237
After heating, why did no microorganisms appear in the infusion while the flask remained upright?
Because dust and microorganisms from the air were trapped in the bend of the swan neck.
238
Was air present in the flask during Pasteur’s experiment?
Yes. Air moved in and out of the flask.
239
Why is “lack of air” an incorrect explanation for no microbial growth?
Because air was present, but microorganisms were prevented from reaching the infusion.
240
What happened when the flask was left upright for months?
The infusion remained sterile indefinitely.
241
What caused microorganisms to appear after the flask was tilted?
The sterile infusion came into contact with dust trapped in the bend of the flask.
242
How quickly did microbes appear after tilting the flask?
Within hours.
243
What key variable caused microbial growth: air or dust?
Dust containing microorganisms.
244
What conclusion did Pasteur’s experiment support?
Microorganisms do not arise spontaneously; they come from pre-existing microorganisms.
245
Which theory did Pasteur’s experiment disprove?
Spontaneous generation.
246
Which theory did Pasteur’s experiment support?
Biogenesis.
247
What is the key conclusion from Pasteur’s swan-neck flask experiment?
Air alone does not cause microbial growth; contamination by microorganisms does.
248
resistance (in microbiology)
Resistance is the ability of microorganisms to withstand or survive the effects of antimicrobial drugs, allowing them to continue growing in the presence of antibiotics.
249
biofilm
A biofilm is a complex aggregation of microorganisms that attach to a surface and are surrounded by a protective matrix, making them more resistant to antibiotics and immune defenses.
250
emerging infectious disease (EID)
An emerging infectious disease is a disease that is new or changing and is increasing in incidence or has the potential to increase in the near future.
251
Why are biofilms important in microbiology?
Biofilms are important because they protect microorganisms, making them more resistant to antibiotics, disinfectants, and the immune system, and they can cause persistent infections.
252
Where are biofilms commonly found?
Biofilms are found on solid surfaces, including rocks in water, teeth, water pipes, and medical implants such as catheters and joint prostheses.
253
Why are bacteria in biofilms more resistant to antibiotics?
The protective matrix of a biofilm acts as a barrier, preventing antibiotics from reaching the bacteria effectively.
254
How can biofilms be both beneficial and harmful?
Biofilms can be beneficial by protecting mucous membranes and serving as food sources in ecosystems, but harmful by clogging pipes and causing chronic infections.
255
What is an infectious disease?
An infectious disease occurs when pathogens invade a susceptible host, grow within the host, and cause disease.
256
What determines whether exposure to a microbe results in disease?
Disease depends on the balance between the body’s defenses and the disease-producing ability of the microorganism.
257
What are the body’s natural defenses against infectious disease?
Natural defenses include the skin, mucous membranes, immune cells, and immune chemicals.
258
What factors contribute to the emergence of infectious diseases?
Evolutionary changes in microbes (e.g., antibiotic resistance) Zoonoses (animal → human transmission) Global travel and transportation Environmental changes (deforestation, construction) Changes in pathogen ecology
259
What are zoonoses?
Zoonoses are infectious diseases transmitted from animals to humans.
260
How does antibiotic resistance develop?
Resistance develops through random mutations; antibiotics kill susceptible bacteria, allowing resistant bacteria to survive and multiply.
261
Why does misuse of antibiotics increase resistance?
Overuse and misuse select for resistant bacteria, creating environments where resistant strains thrive.
262
Why might an infection persist even after antibiotic treatment?
The pathogen may be antibiotic-resistant or protected within a biofilm, preventing the drug from working effectively.
263
normal microbiota
Normal microbiota are microorganisms that normally live on or in the human body and do not cause disease under normal conditions.
264
How do microbes that cause infectious disease differ from normal microbiota?
Microbes causing infectious disease invade tissues, overcome host defenses, and cause damage, resulting in disease.
265
What is the key difference between normal microbiota and infectious microbes?
The key difference is that normal microbiota coexist without causing harm, whereas infectious microbes cause disease when they invade a susceptible host.
266
Why are biofilms important in microbiology?
Biofilms are important because they protect microorganisms, making them more resistant to antibiotics, disinfectants, and immune defenses.
267
How do biofilms contribute to persistent infections?
Biofilms allow microbes to adhere to surfaces and survive treatment, leading to chronic or recurring infections.
268
Why are infections involving biofilms difficult to treat?
The biofilm matrix acts as a barrier, reducing antibiotic penetration and protecting bacteria.
269
What are emerging infectious diseases (EIDs)?
Emerging infectious diseases are new or changing diseases that are increasing in incidence or have the potential to increase.
270
What role does antibiotic resistance play in emerging diseases?
Antibiotic resistance allows previously controlled diseases to reemerge and spread.
271
How does breakdown of public health measures contribute to emerging diseases?
Reduced vaccination and weakened public health systems allow disease transmission to increase.
272
How can environmental and social changes lead to emerging infectious diseases?
Changes such as global travel, deforestation, urbanization, and human–animal contact increase exposure to new pathogens.
273
List the major factors contributing to emerging infectious diseases.
Antibiotic resistance
Breakdown of public health measures
Environmental changes
Global travel and transportation
Zoonotic transmission
Changes in pathogen ecology
274
What is a biofilm?
A biofilm is a complex aggregation of microorganisms that attach to each other and/or to a surface, embedded in a protective matrix.
275
Where can biofilms form?
Biofilms can form on natural surfaces (rocks, teeth) and medical devices (catheters, implants).
276
Why are biofilms medically important?
Bacteria in biofilms are more resistant to antibiotics and harder to eliminate, leading to persistent infections.
277
How do biofilms protect bacteria?
The biofilm matrix acts as a barrier, reducing penetration of antibiotics and immune cells.
278
Why are biofilm-associated infections difficult to treat?
Because bacteria within biofilms are protected and resistant, allowing infections to persist or recur.
279
What is an infectious disease?
A disease in which pathogens invade a susceptible host, multiply, and cause damage to tissues.
280
What determines whether exposure to microbes causes disease?
The balance between host defenses and the disease-producing ability of the microbe.
281
What is resistance (host resistance)?
The ability of the body to ward off disease, using barriers, immune cells, and chemical defenses.
282
What happens if host defenses are insufficient?
Antibiotics or other drugs may be required to control the infection.
283
Why don’t all microbes cause disease?
Because only a minority of microorganisms are pathogenic.
284
What are emerging infectious diseases (EIDs)?
Diseases that are new or changing and are increasing in incidence or have the potential to increase.
285
Name major factors that contribute to emerging infectious diseases.
Antibiotic resistance, Global travel and transportation, Zoonotic transmission (animal → human), Environmental and ecological changes, Breakdown of public health measures.
286
What causes COVID-19?
A coronavirus called SARS-CoV-2.
287
When was COVID-19 first recognized as a pandemic?
March 2020.
288
Why do new COVID-19 variants emerge?
Because viruses mutate, which can increase transmissibility or disease severity.
289
What does “pandemic” mean?
A disease that affects a large number of people worldwide.
290
What is Influenza A?
A virus that infects many animal species and can sometimes cross species barriers to infect humans.
291
Why is Influenza A considered an emerging disease threat?
Because it can mutate, infect new hosts, and gain the ability to spread between humans.
292
What is the concern with avian and swine influenza viruses?
They may adapt for efficient human-to-human transmission.
293
Why must influenza viruses be continuously monitored?
Because they have the potential to change and spread rapidly.
294
Why are biofilms clinically important?
Because they protect bacteria and make them more resistant to antibiotics, leading to persistent infections.
295
What is the key problem with infections involving biofilms?
They are difficult to eliminate because the biofilm provides a protective barrier.
296
What three components are required for an infectious disease to occur?
A pathogen
A susceptible host
Failure of host defenses
297
Why does exposure to microbes not always result in disease?
Because disease depends on the balance between host defenses and the microbe’s ability to cause disease.
298
What are emerging infectious diseases (EIDs)?
Diseases that are new or changing and increasing in incidence or have the potential to increase.
299
List the major factors contributing to emerging infectious diseases.
Antibiotic resistance
Global travel and transportation
Zoonotic transmission (animal → human)
Environmental/ecological changes
Breakdown of public health measures
300
Why is COVID-19 considered an emerging infectious disease?
Because the virus mutates, leading to new variants that may be more transmissible or severe.
301
What does viral mutation allow viruses like SARS-CoV-2 to do?
Create new variants that can spread more easily or cause more severe disease.
302
Why is Influenza A considered a major public health concern?
Because it can mutate, infect multiple animal species, and cross into humans.
303
Why must Influenza A viruses be continuously monitored?
Because they can change rapidly and potentially gain efficient human-to-human transmission.
304
In the nutrient broth experiment, what happens when broth is heated and NOT sealed?
Microbial growth occurs.
305
In the nutrient broth experiment, what happens when broth is heated and THEN sealed?
No microbial growth occurs.
306
In the heated but unsealed nutrient broth, why does microbial growth occur?
Because microorganisms from the environment can enter the flask.
307
In the heated and sealed nutrient broth, why does no microbial growth occur?
Because no new microorganisms can enter after heating.
308
In the nutrient broth heating experiment, which condition determines whether microbes grow?
Whether the flask is sealed or unsealed after heating.
309
The nutrient broth heating and sealing results support which theory: spontaneous generation or biogenesis?
Biogenesis.
310
What does the heated-and-sealed nutrient broth result demonstrate about the origin of microbes?
Microbes arise from preexisting microorganisms, not from nonliving matter.
311
If spontaneous generation were correct, what would be expected in heated and sealed nutrient broth?
Microbial growth would still occur.
312
What idea is disproved when heated, sealed nutrient broth shows no microbial growth?
Spontaneous generation.
313
In the nutrient broth experiment, heating kills existing microbes, and sealing prevents what?
Entry of airborne microorganisms.
314
Why is heating alone not sufficient to prevent microbial growth in nutrient broth?
Because airborne microbes can re-enter if the flask is not sealed.
315
What is the key conclusion of the nutrient broth heating and sealing experiment?
Microbial growth occurs only when microorganisms can enter, supporting biogenesis.
316
Who was Robert Koch (1843–1910)?
A scientist who established experimental steps to directly link a specific microbe to a specific disease.
317
What was Robert Koch’s major contribution to microbiology?
He established experimental steps for directly linking a specific microbe to a specific disease.
318
What problem did Robert Koch’s work address in microbiology?
How to prove that a particular microorganism causes a particular disease.
319
According to the slide, what relationship did Robert Koch establish?
A direct link between a specific microbe and a specific disease.
320
Why are Robert Koch’s experimental steps important in the study of infectious disease?
They provide evidence-based criteria to connect one microbe to one disease.
321
Fill in the blank: Robert Koch established experimental steps for directly linking a ______ to a ______.
Specific microbe → specific disease
322
Did Robert Koch’s work focus on microbes in general or on specific microbes causing specific diseases?
Specific microbes causing specific diseases.
323
When did Robert Koch live?
1843–1910
324
What two things contributed to The Germ Theory of Disease?
Robert Kochs proved that a bacterium causes anthrax
Koch proved that specific microbe causes a specific disease
325
What did Robert Koch do in 1876?
Robert Koch proved that a bacterium causes anthrax
326
What did Robert Koch do in 1881?
provided the experimental steps, Koch postulates to prove that a specific microbe causes a specific disease
327
What years did Jenner live?
1749 - 1823
328
In what year did Edward Jenner perform the first vaccination?
1796
329
What virus did Edward Jenner use to inoculate a subject in 1796?
Cowpox virus
330
What disease did Jenner’s cowpox inoculation protect against?
Smallpox
331
What did Edward Jenner demonstrate by inoculating a subject with cowpox virus?
That exposure to cowpox virus protects against smallpox.
332
From what word is vaccination derived?
Vacca, meaning cow
333
Why is the term vaccination derived from vacca (cow)?
Because cowpox virus was used to protect against smallpox.
334
What is the protection produced by vaccination called?
Immunity
335
In 1796, Edward Jenner inoculated a subject with _____ virus, providing protection from _____, a protection called _____.
Cowpox; smallpox; immunity
336
Place this event on a historical timeline: Jenner’s cowpox inoculation.
1796
337
Did Edward Jenner inoculate subjects with smallpox virus or cowpox virus?
Cowpox virus
338
Summarize Edward Jenner’s contribution to vaccination.
In 1796, Edward Jenner showed that cowpox virus inoculation protects against smallpox, producing immunity, and gave rise to the concept of vaccination.
339
How many names does each organism have in scientific naming?
Two names
340
What are the two names used for each organism in scientific naming?
Genus and specific epithet
341
In scientific names, which part is capitalized?
The genus
342
In scientific names, which part is written in lowercase?
The specific epithet
343
How are scientific names formatted in writing?
Italicized or underlined
344
When would scientific names be underlined instead of italicized?
When italics are not available (handwritten or plain text)
345
Are scientific names localized to one language or used worldwide?
They are Latinized and used worldwide
346
Why are scientific names described as “Latinized”?
They follow Latin-based naming conventions used globally
347
What may scientific names be based on?
They may be descriptive or honor a scientist
348
Each organism has two names: the _____ and the _____.
Genus; specific epithet
349
Which is formatted correctly in scientific naming?
Genus capitalized, specific epithet lowercase, both italicized or underlined
350
Is the specific epithet ever capitalized?
No
351
Summarize the rules for scientific naming of microorganisms.
Each organism has two Latinized names (genus and specific epithet); the genus is capitalized, the specific epithet is lowercase, and both are italicized or underlined.
352
What organism is named Staphylococcus aureus?
A bacterium with clustered, spherical cells and gold-colored colonies
353
In the name Staphylococcus aureus, what does “Staphylo-” describe?
Clustered cells
354
In the name Staphylococcus aureus, what does “cocci” describe?
Spherical cell shape
355
In the name Staphylococcus aureus, what does “aureus” describe?
Gold-colored colonies
356
Which characteristics are described by the name Staphylococcus aureus?
Clustered spherical cells and gold-colored colonies
357
What organism is named Escherichia coli?
A bacterium associated with the large intestine (colon)
358
In the name Escherichia coli, what does “Escherichia” represent?
It honors the discoverer, Theodor Escherich
359
In the name Escherichia coli, what does “coli” describe?
The bacterium’s habitat — the large intestine (colon)
360
Which scientific name honors a scientist?
Escherichia coli
361
Which scientific name describes physical characteristics of the organism?
Staphylococcus aureus
362
How do Staphylococcus aureus and Escherichia coli differ in name meaning?
Staphylococcus aureus describes cell shape, arrangement, and colony color Escherichia coli honors a scientist and describes habitat
363
The scientific name Escherichia coli refers to the bacterium’s habitat, the _____.
Large intestine (colon)
364
What are living things too small to be seen with the unaided eye called?
Microorganisms.
365
Why are microorganisms important to Earth’s ecological balance?
They help maintain Earth’s ecological balance.
366
What term describes the microorganisms that live in and on the human body?
Normal microbiota (or human microbiome).
367
Why is the normal microbiota important to human health?
The normal microbiota are needed to maintain good health.
368
What are two beneficial uses of microorganisms?
They are used to produce foods and chemicals.
369
What is one harmful role of some microorganisms?
Some microorganisms cause disease.
370
Who designed the nomenclature system that assigns two names to each organism?
Carolus Linnaeus (1735).
371
What are the two parts of a scientific name?
A genus and a specific epithet.
372
How are scientific names formatted in writing?
They are italicized or underlined.
373
How are the genus and specific epithet capitalized?
The genus is capitalized; the specific epithet is lowercase.
374
What type of organisms are bacteria?
Unicellular organisms.
375
Why are bacterial cells described as prokaryotic?
They have no nucleus.
376
What is the main component of most bacterial cell walls?
Peptidoglycan.
377
How do most bacteria reproduce?
By binary fission.
378
What structure may bacteria possess for movement?
Flagella.
379
How do bacteria obtain nutrition?
They can use a wide range of chemical substances.
380
What type of cells do archaea have?
Prokaryotic cells.
381
What cell wall component do archaea lack?
Peptidoglycan.
382
What are three major groups of archaea?
Methanogens, extreme halophiles, and extreme thermophiles.
383
What type of cells do fungi have?
Eukaryotic cells (true nucleus).
384
Are most fungi unicellular or multicellular?
Most fungi are multicellular.
385
How do fungi obtain nutrients?
By absorbing organic material from their environment.
386
What type of organisms are protozoa?
Unicellular eukaryotes.
387
How do protozoa obtain nourishment?
By absorption or ingestion through specialized structures.
388
Are algae unicellular or multicellular?
They can be unicellular or multicellular.
389
How do algae obtain nourishment?
By photosynthesis.
390
What important substances do algae produce?
Oxygen and carbohydrates used by other organisms.
391
Are viruses cellular or noncellular?
Noncellular.
392
What type of organisms are viruses parasites of?
Cells.
393
What are viruses composed of?
A nucleic acid core (DNA or RNA) surrounded by a protein coat.
394
What additional structure may surround the viral protein coat?
An envelope.
395
What are the two principal groups of multicellular animal parasites?
Flatworms and roundworms.
396
What collective name is given to flatworms and roundworms?
Helminths.
397
How are the microscopic stages of helminths identified?
By traditional microbiological procedures.
398
What are living things too small to be seen with the unaided eye called?
Microorganisms.
399
Why are microorganisms important to Earth?
They help maintain Earth’s ecological balance.
400
What is the normal microbiota (human microbiome)?
Microorganisms that live in and on the human body.
401
Why is normal microbiota important?
It is needed to maintain good health.
402
How are microorganisms used by humans?
Some are used to produce foods and chemicals.
403
Do all microorganisms cause disease?
No, only some microorganisms cause disease.
404
Who designed the modern nomenclature system for naming organisms?
Carolus Linnaeus (1735).
405
How many names does each living organism have in the Linnaean system?
Two names.
406
What are the two parts of a scientific name?
The genus and the specific epithet.
407
How are scientific names written?
Underlined or italicized.
408
How are genus and specific epithet capitalized?
Genus is capitalized; specific epithet is lowercase.
409
What type of cells do bacteria have?
Prokaryotic cells (no nucleus).
410
Are bacteria unicellular or multicellular?
Unicellular.
411
What type of cell wall do most bacteria have?
A peptidoglycan cell wall.
412
How do most bacteria reproduce?
By binary fission.
413
What structure may bacteria possess for movement?
Flagella.
414
How do bacteria obtain nutrients?
They can use a wide range of chemical substances.
415
Are archaea prokaryotic or eukaryotic?
Prokaryotic.
416
What do archaea lack in their cell walls?
Peptidoglycan.
417
Name three groups of archaea.
Methanogens, extreme halophiles, and extreme thermophiles.
418
What type of cells do fungi have?
Eukaryotic cells.
419
Are most fungi unicellular or multicellular?
Multicellular.
420
How do fungi obtain nutrients?
By absorbing organic material from their environment.
421
What type of organisms are protozoa?
Unicellular eukaryotes.
422
How do protozoa obtain nourishment?
By absorption or ingestion through specialized structures.
423
Are algae unicellular or multicellular?
They can be unicellular or multicellular.
424
How do algae obtain nourishment?
By photosynthesis.
425
What do algae produce that other organisms use?
Oxygen and carbohydrates.
426
Are viruses cellular or noncellular?
Noncellular.
427
What are viruses parasites of?
Cells.
428
What is the basic structure of a virus?
A nucleic acid core (DNA or RNA) surrounded by a protein coat.
429
What may surround the viral protein coat?
An envelope.
430
What are helminths?
Multicellular animal parasites.
431
What are the two principal groups of helminths?
Flatworms and roundworms.
432
How are microscopic stages of helminths identified?
By traditional microbiological procedures.
433
Into how many domains are all organisms classified?
Three.
434
What are the three domains of life?
Bacteria, Archaea, and Eukarya.
435
What groups are included in the domain Eukarya?
Protists, fungi, plants, and animals.
436
Whose observations helped establish the cell theory?
Robert Hooke.
437
What does cell theory state?
All living things are composed of cells.
438
Who first observed microorganisms and when?
Anton van Leeuwenhoek in 1673.
439
What is spontaneous generation?
The idea that living organisms arise from nonliving matter.
440
Who showed maggots appear only when flies lay eggs on meat?
Francesco Redi (1668).
441
Who claimed microorganisms could arise spontaneously in heated broth?
John Needham (1745).
442
Who argued microorganisms came from air entering broth?
Lazzaro Spallanzani (1765).
443
What is biogenesis?
Living cells arise only from preexisting cells.
444
Who introduced the concept of biogenesis?
Rudolf Virchow (1858).
445
Who provided experimental proof of biogenesis?
Louis Pasteur (1861).
446
What laboratory practices resulted from Pasteur’s work?
Aseptic techniques.
447
When did the first Golden Age of Microbiology occur?
Approximately 1857–1914.
448
What did Pasteur discover about fermentation?
Yeasts ferment sugars to alcohol; bacteria oxidize alcohol to acetic acid.
449
What is pasteurization used for?
Killing bacteria in milk and some alcoholic beverages.
450
Who introduced disinfectants in surgery?
Joseph Lister.
451
Who proved microorganisms cause disease?
Robert Koch.
452
What are Koch’s postulates used for?
Proving a specific microorganism causes a specific disease.
453
Who demonstrated immunity to smallpox using cowpox?
Edward Jenner.
454
What is immunity?
Protection against disease.
455
How are modern vaccines prepared?
From living avirulent microbes, killed pathogens, pathogen components, or recombinant DNA techniques.
456
What are the three domains of life?
Bacteria, Archaea, and Eukarya.
457
What groups are included in the domain Eukarya?
Protists, fungi, plants, and animals.
458
Whose observations laid the groundwork for the development of cell theory?
Robert Hooke.
459
What is cell theory?
The concept that all living things are composed of cells.
460
Who was the first to observe microorganisms?
Anton van Leeuwenhoek.
461
What year did Anton van Leeuwenhoek first observe microorganisms?
1673.
462
What tool did Anton van Leeuwenhoek use to observe microorganisms?
A simple microscope.
463
What is spontaneous generation?
The idea that living organisms could arise from nonliving matter.
464
Until when did many people believe in spontaneous generation?
Until the mid-1800s.
465
Who demonstrated that maggots appear on decaying meat only when flies can lay eggs on it?
Francesco Redi.
466
What year did Francesco Redi demonstrate this finding?
1668.
467
Who claimed that microorganisms could arise spontaneously from heated nutrient broth?
John Needham.
468
What year did John Needham make this claim?
1745.
469
Who repeated Needham’s experiments and suggested microorganisms came from the air?
Lazzaro Spallanzani.
470
What year did Spallanzani publish his findings?
1765.
471
What is biogenesis?
The concept that living cells can arise only from preexisting cells.
472
Who introduced the concept of biogenesis?
Rudolf Virchow.
473
What year did Rudolf Virchow introduce biogenesis?
1858.
474
Who demonstrated that microorganisms are present in the air and provided proof of biogenesis?
Louis Pasteur.
475
What year did Louis Pasteur provide proof of biogenesis?
1861.
476
What major laboratory practice developed as a result of Pasteur’s discoveries?
Aseptic techniques.
477
What are aseptic techniques used for?
To prevent contamination by microorganisms in laboratory and medical procedures.
478
During what years did microbiology advance rapidly in the First Golden Age?
Between 1857 and 1914.
479
What did Pasteur discover about yeast?
Yeasts ferment sugars to alcohol.
480
What did Pasteur discover bacteria can do to alcohol?
Oxidize alcohol to acetic acid.
481
What is pasteurization?
A heating process used to kill bacteria.
482
Pasteurization is used to kill bacteria in which products?
Some alcoholic beverages and milk.
483
Who showed a causal relationship between microorganisms and disease in 1835?
Agostino Bassi.
484
Who also demonstrated a causal relationship between microorganisms and disease in 1865?
Louis Pasteur.
485
Who introduced the use of disinfectants to clean surgical wounds?
Joseph Lister.
486
In what decade did Joseph Lister introduce disinfectants in surgery?
The 1860s.
487
Who proved that microorganisms cause disease?
Robert Koch.
488
What are Koch’s postulates?
A sequence of procedures used to prove that a specific microorganism causes a specific disease.
489
What year were Koch’s postulates introduced?
1876.
490
Who demonstrated that inoculation with cowpox provides immunity to smallpox?
Edward Jenner.
491
What year did Edward Jenner demonstrate immunity to smallpox?
1798.
492
What did Pasteur discover about avirulent bacteria around 1880?
They could be used as vaccines for fowl cholera.
493
How are modern vaccines prepared?
From living avirulent microorganisms, killed pathogens, isolated components of pathogens, or recombinant DNA techniques.
494
What discovery marked the beginning of the Second Golden Age of Microbiology?
The discovery of penicillin’s effectiveness against infections.
495
What are the two types of chemotherapeutic agents?
Synthetic drugs and antibiotics.
496
What are synthetic drugs?
Chemically prepared drugs made in the laboratory.
497
What are antibiotics?
Substances produced naturally by bacteria and fungi that inhibit the growth of bacteria.
498
Who introduced an arsenic-containing chemical to treat syphilis?
Paul Ehrlich.
499
What was the name of the arsenic-containing chemical used to treat syphilis?
Salvarsan.
500
In what year was salvarsan introduced?
1910.
501
Who observed that a Penicillium fungus inhibited bacterial growth?
Alexander Fleming.
502
What did Alexander Fleming name the active ingredient that inhibited bacterial growth?
Penicillin.
503
In what year was penicillin identified?
1928.
504
What is bacteriology the study of?
Bacteria.
505
What is mycology the study of?
Fungi.
506
What is parasitology the study of?
Parasitic protozoa and worms.
507
Developing a vaccine against which virus is a current research interest in immunology?
HIV.
508
What has advanced knowledge in virology?
New techniques in molecular biology and microscopy.
509
What technological development has helped advance all areas of microbiology?
Recombinant DNA technology.
510
What is genomics?
The study of all of an organism’s genes.
511
How are microbiologists using genomics today?
To study microbiomes in different environments and develop new applications of recombinant DNA technology.
512
What major problem are researchers addressing in the Third Golden Age of Microbiology?
Drug-resistant microbes.
513
What two factors determine whether a person will contract a disease?
The disease-producing properties of a species of microbe and the host’s resistance.
514
What are biofilms?
Bacterial communities that form slimy layers on surfaces.
515
What is an infectious disease?
A disease in which pathogens invade a susceptible host.
516
What does EID stand for?
Emerging infectious disease.
517
What is an emerging infectious disease (EID)?
A new or changing disease showing an increase in incidence in the recent past or a potential to increase in the near future.
518
How did the idea of spontaneous generation come about?
People believed living organisms could arise from nonliving matter.
519
What role do microorganisms play in biological control of pests?
They are used to control insect pests.
520
What role do microorganisms play in recycling of elements?
They recycle elements in the environment.
521
What role do microorganisms play as normal microbiota?
They live in and on the human body.
522
What role do microorganisms play in sewage treatment?
They decompose organic matter in sewage.
523
What role do microorganisms play in human insulin production?
They are used to produce human insulin.
524
What role do microorganisms play in vaccine production?
They are used to produce vaccines.
525
What role do microorganisms play in biofilms?
They form bacterial communities that attach to surfaces.
526
Which field of microbiology involves growing microbes to produce fermented foods?
Biotechnology.
527
Which field studies the causative agent of Ebola virus disease?
Virology.
528
Which field studies the production of human proteins by bacteria?
Microbial genetics.
529
Which field studies the symptoms of AIDS?
Immunology.
530
Which field studies the production of toxin by E. coli?
Microbial physiology.
531
Which field studies biodegradation of pollutants?
Microbial ecology.
532
Which field develops gene therapy for a disease?
Molecular biology.
533
Which field studies the fungus Candida albicans?
Mycology.
534
Which microorganisms are not composed of cells?
Viruses
535
Which microorganisms have a cell wall made of chitin?
Fungi
536
Which microorganisms have a cell wall made of peptidoglycan?
Bacteria
537
Which microorganisms have a cell wall made of cellulose and are photosynthetic?
Algae
538
Which microorganisms are unicellular, have complex cell structure, and lack a cell wall?
Protozoa
539
Which microorganisms are multicellular animals?
Helminths
540
Which microorganisms are prokaryotes without peptidoglycan in their cell wall?
Archaea
541
Why would someone buy Bacillus thuringiensis in a retail store?
It is used as a biological control to kill insect pests.
542
Why would someone buy Saccharomyces in a retail store?
It is used in fermentation, such as making bread and alcoholic beverages.
543
What type of microorganism has a peptidoglycan cell wall, DNA not contained in a nucleus, and flagella?
Bacteria
544
Where did airborne microbes end up in Pasteur’s experiment?
Airborne microorganisms became trapped in the bend of the swan-neck flask and did not reach the broth.
545
Which of the following is a scientific name?
a. Mycobacterium tuberculosis
b. Tubercle bacillus
a. Mycobacterium tuberculosis
Why: Scientific names use genus + species and are italicized.
546
Q: Which of the following is not a characteristic of bacteria?
a. are prokaryotic
b. have peptidoglycan cell walls
c. have the same shape
d. grow by binary fission
e. have the ability to move
c. have the same shape
Why: Bacteria come in different shapes (cocci, bacilli, spirilla).
547
Which of the following is the most important element of Koch’s germ theory of disease? The animal shows disease symptoms when
a. the animal has been in contact with a sick animal
b. the animal has a lowered resistance
c. a microorganism is observed in the animal
d. a microorganism is inoculated into the animal
e. microorganisms can be cultured from the animal
d. a microorganism is inoculated into the animal
Why: Koch’s postulates require that the microorganism causes disease when introduced into a healthy host.
548
Recombinant DNA is
a. DNA in bacteria
b. the study of how genes work
c. the DNA resulting when genes of two different organisms are mixed
d. the use of bacteria in the production of foods
e. the production of proteins by genes
c. the DNA resulting when genes of two different organisms are mixed
549
Which of the following statements is the best definition of biogenesis?
a. Nonliving matter gives rise to living organisms.
b. Living cells can only arise from preexisting cells.
c. A vital force is necessary for life.
d. Air is necessary for living organisms.
e. Microorganisms can be generated from nonliving matter.
b. Living cells can only arise from preexisting cells.
Why: Biogenesis states that life comes only from existing life, not from nonliving matter.
550
Which of the following is a beneficial activity of microorganisms?
a. Some microorganisms are used as food for humans.
b. Some microorganisms use carbon dioxide.
c. Some microorganisms provide nitrogen for plant growth.
d. Some microorganisms are used in sewage treatment processes.
e. all of the above
e. all of the above
Why: Microorganisms are beneficial in many ways, including food production, carbon cycling, nitrogen fixation, and sewage treatment.
551
It has been said that bacteria are essential for the existence of life on Earth. Which of the following is the essential function performed by bacteria?
a. control insect populations
b. directly provide food for humans
c. decompose organic material and recycle elements
d. cause disease
e. produce human hormones such as insulin
c. decompose organic material and recycle elements
Why: Bacteria break down dead organic matter and recycle chemical elements, making nutrients available again for living organisms.
552
Which of the following statements about E. coli is false?
a. E. coli was the first disease-causing bacterium identified by Koch.
b. E. coli is part of the normal microbiome of humans.
c. E. coli is beneficial in human intestines.
d. E. coli gets nutrients from intestinal contents.
e. None of the above; all the statements are true.
a. E. coli was the first disease-causing bacterium identified by Koch.
Why: Robert Koch’s first identified disease-causing bacterium was Mycobacterium tuberculosis, not E. coli.
Microbiology
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