Module 1 - The Microbial World Flashcards
1
Q
What is microbiology?
A
The study of microorganisms
2
Q
What are some examples of microorganisms?
A
Bacteria, protozoa, and fungi
3
Q
True or false: microbes can be seen with the naked eye
A
False: most cannot be seen with the naked eye
4
Q
Why do we need to study microbiology?
A
Microbes have a complex and dynamic relationship with humans
5
Q
How can bacteria be harmful to humans?
A
By causing infectious diseases
6
Q
How can bacteria be helpful to humans?
A
By aiding in digestion and immune system development
7
Q
True or false: microorganisms only affect animals
A
False: they can also impact plants
8
Q
Where is microbiology used?
A
In biotechnology and the food industry
9
Q
How is microbiology used in biotechnology?
A
By using microbes to create drugs
10
Q
How is microbiology used in the food industry?
A
By creating food such as milk, butter, bread, and cheese
11
Q
What is the definition of life?
A
A self-organizing, self replicating, non-equilibrium system
12
Q
What is the purpose of life?
A
To preserve and reinforce its existence in the environment
13
Q
What are some characteristics of life?
A
Metabolism, growth, reproduction, genetic variation/evolution, response/adaptation to the external environment, homeostasis
14
Q
What macromolecules are needed for life?
A
Proteins, lipids, carbohydrates, and nucleic acids
15
Q
What are the subunits of polypeptides?
A
Amino acids
16
Q
What are the subunits of nucleic acids?
A
Deoxyribonucleotides and ribonucleotides
17
Q
What are the subunits of lipids?
A
Diverse structures
18
Q
What are the subunits of carbohydrates?
A
Sugars
19
Q
What are the functions of proteins?
A
Catalyze biochemical reactions (enzymes) and act as structural components
20
Q
What are the functions of nucleic acids?
A
Store hereditary information (DNA), and produce polypeptides (RNA)
21
Q
What are the functions of lipids?
A
Make up cell membrane to separate interior and exterior
22
Q
What are the functions of polysaccharides?
A
Energy storage (glycogen, starch) and structure (chitin, cellulose)
23
Q
What are the most abundant molecules in cells?
A
Proteins and polypeptides
24
Q
Which are more abundant in a cell: RNA or DNA?
A
RNA
25
What is the difference between a protein and a polypeptide?
The function
26
How is the shape of a polypeptide different than a protein?
Long polypeptide chains fold into proteins, which have a well defined structure
27
What is the function of the cell membrane?
Separate external and internal cell compartments
28
Before the 1970s, how were organisms classified?
As prokaryotes or eukaryotes
29
What are prokaryotes?
Organisms with no membrane-bound organelles
30
What are eukaryotes?
Organisms with membrane-bound organelles
31
Today, how are organisms classified?
Into 3 domains
32
What are the 3 domains of life?
Bacteria, archaea, and eukarya
33
What is the basis for the 3 domains of life?
Differences in the 16S rRNA gene
34
In a phylogenetic tree of life, what does the linear distance represent?
Proportional to the sequence similarity of the 16S rRNA gene in those two organisms (evolutionary distance)
35
How has the tree of life been updated recently (2016)?
By analyzing 16 ribosomal proteins other than the 16S rRNA gene
36
What is the significance of the 16S rRNA gene?
Determines the tree of life evolutionary distance through sequence analysis
37
What is the purpose of using 16 ribosomal proteins (instead of the 16S rRNA gene) for the tree of life?
Updated resolution
38
True or false: bacteria have a nuclear membrane
False
39
True or false: archaea have a nuclear membrane
False
40
True or false: eukarya have a nuclear membrane
True
41
True or false: bacteria commonly have membrane-bound organelles
False: it is rare, only found in a few species
42
True or false: archaea commonly have membrane-bound organelles
False: it is rare, only found in a few species
43
True or false: eukarya commonly have membrane-bound organelles
True: multiple distinct types are found in all species
44
Which domain(s) have a nuclear membrane?
Eukarya
45
Which domain(s) have membrane-bound organelles?
Eukarya
46
Describe the plasma membrane of bacteria (in terms of the other domains)
Similar to eukarya
47
Describe the plasma membrane of eukarya (in terms of the other domains)
Similar to bacteria
48
Describe the plasma membrane of archaea (in terms of the other domains)
Different from eukarya and bacteria
49
Which domains have similar plasma membranes?
Bacteria and eukarya
50
Describe the cell wall of bacteria (generally)
Found in nearly all species, made up of peptidoglycans
51
Describe the cell wall of archaea (generally)
Found in nearly all species, made up of various materials
52
Describe the cell wall of eukarya (generally)
Found in some species, made up of various materials
53
How many RNA polymerases do bacteria have?
One
54
How many RNA polymerases do eukarya have?
Three (RNA pol I, II, and III)
55
How many RNA polymerases do archaea have?
One (Eukaryal-like RNA pol II)
56
True or false: bacteria have histones
False: they have histone-like proteins
57
True or false: archaea have histones
True
58
True or false: eukarya have histones
True
59
Which domain(s) have histones?
Archaea and eukarya
60
What was the early environment on Earth like?
Little oxygen, and a soup of chemicals
61
What happened to the soup of chemicals in early Earth?
They became macromolecules and single cells
62
When did oxygen producing bacteria come into existance?
About 3 billion years ago
63
When was the oxygen atmosphere established on Earth?
About 2 billion years ago
64
How were eukaryotes formed on early Earth?
Through endosymbiosis
65
What is the endosymbiotic theory?
Primitive prokaryotic microbes ingested other microbes, starting a symbiotic relationship, forming the first basic eukaryotes
66
What does the endosymbiotic theory describe?
How eukaryotic organisms first appeared on early Earth from prokaryotic organisms
67
How did the two organisms interact under the endosymbiotic theory?
One lived inside the other, with them both acting as a single organism
68
What does symbiosis mean?
The interaction between two different organisms living in close physical association, usually to the advantage of both
69
Which organelles arose from an endosymbiotic process?
Chloroplasts and mitochondria
70
How did mitochondria benefit other cells?
By using oxygen to produce chemical energy (respiration)
71
How did chloroplasts benefit other cells?
By fixing carbon to create sugar molecules (photosynthesis)
72
How long have bacteria dominated the Earth?
About 3.5 billion years
73
What was the purpose of the Miller-Urey experiment?
To show that organic molecules could arise from early Earth conditions
74
When was the Miller-Urey experiment performed?
In the 1950s
75
What is the purpose of water in the Miller-Urey experiment?
It was critical to convert inorganic molecules into organic molecules
76
What was the purpose of the spark in the Miller-Urey experiment?
Simulate lightning that could be a source of energy for the biochemical reactions to occur
77
What was the conclusion of the Miller-Urey experiment?
Organic molecules can be formed with light and water
78
What are some fundamental questions (4) regarding the origin of life?
1. How are macromolecules produced?
2. What was the source of genetic information?
3. What catalyzed biochemical reactions?
4. What separated interior from exterior?
79
Where is iron found on Earth?
In the inner core
80
What was the significance of iron in the early Earth?
It could act as a surface for molecules to stick to and form macromolecules
81
What is needed for a cell to replicate?
Biochemical reactions, and a genetic component
82
What are ribozymes?
RNA that can catalyze biochemical reactions
83
How come RNA could support independent life forms?
They could act as a catalyst for biochemical reactions, and a genetic component (dual purpose for replication)
84
What was an early form of the plasma membrane?
Micelles
85
What are micelles?
A single layer of phospholipids that can separate interior from exterior
86
How come plasma membranes are composed of a bilayer, and not a monolayer?
The size of a micelle is more limited than a bilayer
87
What were the components of the earliest microbes?
Micelles and RNA
88
Why is DNA used to store hereditary information now instead of RNA?
DNA has a backup copy (double strand), and it is more stable than RNA
89
What are the advantages of microbes (4 reasons)?
1. Fast and easy to grow
2. Produce enzymes and other molecules for industrial/medical uses
3. Simpler to study (less genes)
4. Easier genetic manipulation (compared to eukaryotic cell)
90
How long does E. coli take to divide?
20 min
91
How long does yeast take to divide?
90 min
92
Before microbes were discovered, what was believed to be the source of diseases?
Angry gods or bad air
93
How did microbiology begin?
Through the development of the microscope
94
What did Anton van Leeuwenhoek do?
First observed microbes with 300x magnification lens
95
Who is considered the father of microbiology?
Anton van Leeuwenhoek
96
When was Leeuwenhoek's work with microorganisms?
1676
97
What did Robert Hooke do?
Developed cell theory
98
What is cell theory?
The theory that all living things are made up of cells
99
Which scientist first observed microorganisms?
Anton van Leeuwenhoek
100
Which scientist developed cell theory?
Robert Hooke
101
What is the spontaneous generation theory?
The theory that life arises from nonliving matter
102
Which scientist first studied spontaneous generation theory?
John Needham
103
What did John Needham do?
Heated a nutrient broth, and placed it in a covered flask. He observed microbial growth, and supported spontaneous generation
104
What is biogenesis?
The theory that living cells only arise from preexisting living cells
105
Which scientist first studied biogenesis?
Lazzaro Spallanzani
106
What did Lazzaro Spallanzani do?
Sealed nutrient broth in a flask, and heated it. He observed no microbial growth, and supported biogenesis
107
What would be the consequence of spontaneous generation theory if it was accurate?
There would be no need to study transmission or prevention of microbial diseases
108
Which experiment settled the spontaneous generation / biogenesis debate?
Louis Pasteur's experiment
109
What did Louis Pasteur do?
Perform an experiment with an S-shaped flask to prove the biogenesis theory
110
What are the steps (2) of the Pasteur experiment?
1. Heat a nutrient broth in an S-shaped flask
| 2. Then, tilt the flask to reach the neck
111
What is the significance of the S-shaped flask?
It could trap microorganisms from the air
112
What was the result of the first half of the Pasteur experiment?
There was no microbial growth
113
What was the conclusion of the first half of the Pasteur experiment?
Microbes could not grow, since none were present
114
What was the result of the second half of the Pasteur experiment?
There was microbial growth
115
What was the conclusion of the second half of the Pasteur experiment?
Microbes could grow, since they came from the air
116
What was the significance of tilting the flask in the Pasteur experiment?
It brought the microbes from the air in contact with the nutrient broth
117
What is pasteurization?
The application of high heat for a brief period of time
118
What is the purpose of pasteurization?
To inactivate microorganisms (example: extend shelf life)
119
Where is pasteurization used?
In the food industry to extend shelf life
120
What is the difference between pasteurization and sterilization?
Sterilization kills spores, while pasteurization does not
121
What did Robert Koch do?
Found new procedures for growing bacteria, and developed germ theory
122
Who found new procedures for growing bacteria?
Robert Koch
123
What new procedure did Robert Koch develop?
Using solidified agar (liquid culture media)
124
Who developed germ theory?
Robert Koch
125
What is germ theory?
A specific organism causes a specific disease
126
What are Koch's postulates?
A set of 4 rules to determine the cause of an infectious disease
127
What diseases did Koch work with?
Anthrax and tuberculosis
128
Throughout history, what has killed the most humans?
Infectious diseases
129
What was the most fatal pandemic in human history?
The black death
130
How come the black death was so deadly?
People didn't understand the cause of the infectious disease (bacteria)
131
What is the current trend of mortality due to infectious diseases?
Steadily decreasing
132
How come the mortality due to infectious diseases is steadily decreasing?
Better prevention and treatment procedures
133
What are some examples of prevention measures?
Use of antiseptics, sanitation improvements, food/water safety (pasteurization), personal hygiene improvements, and vaccination
134
What are some examples of treatment measures?
Antibiotics
135
What is an antispetic?
A substance that can kill bacteria and stop infection
136
What scientist first used antiseptics?
Joseph Lister
137
What did Joseph Lister do?
Practiced infection control through the use of antiseptics during surgery
138
What did Alexander Fleming do?
Discovered penicillin
139
Who discovered penicillin?
Alexander Fleming
140
What did Jonas Salk and Albert Sabin do?
Developed poliovirus vaccines
141
Who developed poliovirus vaccines?
Jonas Salk and Albert Sabin
142
What did Lynn Margulis do?
Proposed the endosymbiotic theory
143
Who proposed the endosymbiotic theory?
Lynn Margulis
144
What did Kary Mullis do?
Invented PCR
145
Who invented PCR?
Kary Mullis
146
What did Carl Woese do?
Proposed the 3 domain classification of living things
147
Who proposed the 3 domain classification of living things?
Carl Woese
148
What did Craig Venter do?
Published the first complete bacterial genome sequence
149
Who published the first complete bacterial genome sequence?
Craig Venter
150
What is the difference between microorganisms and microbes?
Microorganisms include only living organisms, while microbes includes microorganisms and viruses
151
What is metabolism?
A controlled set of chemical reactions that extract energy and nutrients from the environment, and transform them into new biological materials
152
What is growth?
An increase in mass of biological material
153
What is reproduction?
The production of new copies of the organism
154
What is evolution?
Inherited change within a population
155
What is homeostasis?
Active regulation of their internal environment to maintain relative constancy
156
What are some characteristics of life?
Metabolism, growth, reproduction, evolution, homeostasis, and adaptation
157
What is special about Dictyostelium discoideum?
It can form a complex "multicellular" structure
158
When is Dictyostelium discodeum a unicellular organism?
When food is plentiful
159
When is Dictyostelium discodeum a complex "multicellular" structure
When food is limited
160
What does glycogen phosphorylase do?
Converts glycogen into glucose monomers
161
What are the cell walls of plants made out of?
Cellulose
162
What are the cell walls of fungi made out of?
Chitin
163
What is phylogeny?
Evolutionary history
164
True or false: evolutionary relationships of microbes can easily be determined through fossils
False: microbes do not fossil well
165
What microbe fossils have been observed?
Stromatolites built on layers of photosynthetic bacteria
166
What are the steps of PCR?
1. DNA is heated, causing it to denature
2. Primers anneal to complementary regions
3. DNA polymerase makes more DNA
167
When viruses are not attached to a host, how do they act?
Inert
168
How are viruses "inert" when not attached to a host?
They have no metabolism, and do not respond to stimuli
169
How do viruses "reproduce"?
They disassemble and reassemble inside cellular organisms after genetic material has been replicated and new viral proteins are made
170
How can viruses be used for basic science?
They can help uncover how processes in cells work (how the machinery works)
171
What did Paul Ehrlich do?
Studied the differences between bacterial and eukaryotic cells
172
What was the danger of arsphenamine?
It killed both bacteria and host cells
173
Who studied how drugs could be used to target only prokaryotic cells?
Paul Ehrlich
174
How come the atmosphere of Earth changed over time?
The actions of microbes that evolved throughout Earth's history
175
What surface could have been seen in early Earth?
Iron pyrite (FeS2)
176
What is the importance of iron pyrite?
It is an insoluble, positive charged surface with an affinity for organic molecules
177
What are the controversies surrounding the Miller-Urey experiments?
The exact composition of the early atmosphere is not known, and it can impact the results of the experiment
178
What does 16S rRNA analysis of chloroplasts and mitochondria suggest?
They are closely related to certain kinds of bacteria
179
Which was first: mitochondria or chloroplasts?
Mitochondria
180
How come mitochondria came first in the endosymbiosis theory?
They energy that they provide is valuable, and found in most eukaryotic cells
181
What is a progenote?
A cell hypothesized to store information in genes not yet linked together on chromosomes
182
What is needed for Darwinian evolution?
1. Genetic variation in a population
2. The environment exerting selective pressures
3. Differential reproductive success among genetic variants
183
How come progenotes would be subjected to laws of Darwinian evolution?
Genetic variation and mutation was quite high in these early cells
184
What is a mutation?
A heritable change in the genome
185
What is the purpose of mutations?
They are the ultimate source of variation in a genome
186
What is horizontal gene transfer?
Exchanging genes between cells
187
True or false: genetic material can not be transferred between domains
False: genetic material can be transferred between domains
188
What is recombinant DNA?
DNA fragments stitched together into one molecule
189
What is the importance of recombinant DNA?
It allows for microbes to produce useful compounds
190
How is recombinant DNA created?
1. Plasmids are isolated from bacteria
2. DNA can be inserted using restriction endonucleases
3. The recombinant plasmid can be added back into the bacteria
191
True or false: bacteria can inhabit more diverse environments than eukarya
True: they have more varied metabolisms
192
What dictates the habitat where a bacterium lives?
Its metabolic capabilities
193
What are heterotrophs?
Organisms that feed on organic matter
194
What are autotrophs?
Organisms that can create their own organic matter
195
How does cyanobacteria regain its lost electrons?
Through the splitting of water
196
What is the chemical reaction for the splitting of water?
2H2O --> 4H+ + 4e- + O2
197
What is glycolysis?
The reaction to convert glucose into pyruvate to generate 2ATP molecules
198
What is the chemical reaction for glycolysis?
Glucose + 2ADP + 2Pi + 2NAD+ --> 2Pyruvate + 2ATP + 2NADH + 2H+
199
What is fermentation?
A process to recreate NAD+ from NADH
200
What are the products of fermentation?
NADH and either ethanol + CO2 or lactate
201
What is the problem with fermentation?
It is not effective for generating energy (ATP)
202
What is respiration?
The process of completely oxidizing pyruvate to create ATP
203
True or false: respiration requires oxygen
False: it just needs a final electron acceptor
204
What is needed for respiration to occur?
A final electron acceptor (usually oxygen or sulfur)
205
What is the importance of respiration?
It allows for a lot of energy to be created from glucose
206
What is the danger of respiration?
It can create dangerous and reactive byproducts of oxygen, which could damage cells
207
How come UV light is dangerous to cells?
It causes damaging chemical reactions to DNA
208
How come aquatic life is protected from UV?
UV light cannot penetrate water well
209
How does oxygen help with UV?
Oxygen creates ozone, which can help block UV radiation
210
How did atmospheric oxygen lead to the colonization of microbes on land?
It allowed for protection from UV
211
What is the biosphere?
Regions of Earth that can support life
212
What is biogeochemical cycling?
The transitioning of various chemicals between organic and inorganic forms
213
What is nitrogen fixation?
Converting atmospheric nitrogen to ammonia
214
What is ammonification?
Using decomposition to create ammonia
215
What is nitrification?
Converting ammonia into nitrates and nitrites
216
What is denitrification?
Converting nitrates and nitrites into atmospheric nitrogen
217
What is assimilation?
The process of plants and animals incorporated nitrates, nitrites, and ammonia (useable forms of nitrogen)
218
What is a nitrite?
NO2-
219
What is a nitrate?
NO3-
220
What is NO3-?
Nitrate
221
What is NO2-?
Nitrite
222
What is ammonia?
NH3
223
What is NH3?
Ammonia
224
What is atmospheric nitrogen?
N2
225
What is N2?
Atmospheric nitrogen
226
What is the process of converting atmospheric nitrogen into ammonia?
Nitrogen fixation
227
What is the process of converting ammonia into nitrites and nitrates?
Nitrification
228
What is the process of converting nitrites and nitrates into atmospheric nitrogen?
Denitrification
229
What is the process of plants and animals incorporating useable nitrogen?
Assimilation
230
What is the process of decomposing plant matter into ammonia?
Ammonification
231
How do microbes live?
In complex communities
232
Who studied anthrax and tuberculosis?
Robert Koch
233
What did Alexandre Yersin do?
Discovered that the cause of the Black Death was Yersinia pestis
234
How did most people in war die?
Through infections of microbes
235
What was the first major antibiotic drug?
Penicillin
236
How do vaccines work?
They expose a person to an inactivated or weakened version of a microbe to create immunity to a disease
237
What did Edward Jenner do?
Inoculated a boy with cowpox to provide resistance to smallpox
238
Who inoculated a box with cowpox to provide resistance to smallpox?
Edward Jenner
239
What is the great epidemological divide?
People in developing countries without access to adequate health care suffer a disproportionate infectious disease burden
