Scope Of Microbiology Flashcards
1
Q
The major groups of organisms studied in microbiology are —
A
bacteria, algae, fungi, viruses, and protozoa.
2
Q
— is the study of microbes, organisms so small that a microscope is needed to study them.
A
Microbiology
3
Q
Single-celled organisms with various shapes (spherical, rod, spiral). Lack a nucleus and membrane-bound organelles.
A
Bacteria
4
Q
Similar to bacteria, single-celled, no nucleus.
Genetically and metabolically distinct; often extremophiles.
A
Archaea
5
Q
Single or multicellular, with a nucleus and intracellular structures. Photosynthetic, important food sources, mostly non-pathogenic.
A
Algae
6
Q
Single or multicellular with a nucleus.
Absorb nutrients, decomposers, some cause diseases or produce antibiotics.
A
Fungi
7
Q
Acellular, extremely small, need host cells to replicate. Can cause diseases; include viroids and prions.
A
Viruses
8
Q
Single-celled with a nucleus, can move, some are pathogenic.
A
Protozoa
9
Q
Macroscopic, can cause or transmit diseases through microscopic stages.
A
Helminths and Arthropods
10
Q
Biblical sanitation laws, such as waste burial and leper isolation, influenced preventive medicine.
A
Mosaic Laws
11
Q
Linked diseases with symptoms, recognized disease transmission.
A
Hippocrates
12
Q
Noted immunity in plague survivors.
A
Thucydides
13
Q
Proposed microscopic organisms cause disease.
A
Varro
14
Q
Mentioned “seeds” of disease.
A
Lucretius
15
Q
Plague killed millions in Europe during the 14th century.
A
Black Death
16
Q
Coined “cell” observing cork.
A
Robert Hooke 1665
17
Q
Observed microorganisms, advanced microbiology.
A
Anton van Leeuwenhoek
18
Q
Developed a classification system.
A
Carolus Linnaeus
19
Q
Formulated by Schleiden and Schwann, identifying cells as life’s fundamental units.
A
Cell theory
20
Q
4 Divisions and Significance of Microbiology
A
Immunology
Virology
Chemotherapy
Microbial Genetics
21
Q
• Immunization was first used against smallpox; Jenner used fluid from cowpox blisters to immunize against it.
A
Immunology
22
Q
Beijerinck characterized viruses as pathogenic molecules that could take
over a host cell’s mechanisms for their own use.
nucleic acids could be studied.
A
Virology
23
Q
Reed demonstrated that mosquitoes carry the yellow fever agent, and several other investigators identified viruses in the early twentieth century. The structure of DNA—the genetic material in many viruses and in all cellular organisms—was discovered by Watson and Crick.
A
Virology
24
Q
Techniques for isolating, propagating, and analyzing viruses were developed. Viruses could then be observed and in many cases crystallized, and their nucleic acids could be studied.
A
Virology
25
• Pasteur developed techniques to weaken organisms so they would produce immunity without producing disease.
Immunology
26
• Griffith discovered that previously harmless bacteria could change their nature and become capable of causing disease. This genetic change was shown by Avery, McCarty, and MacLeod to be due to DNA. Tatum and Beadle studied biochemical mutants of Neurospora to show how genetic information controls metabolism.
Genetics and Molecular Biology
27
The Human Genome Project has identified the location and sequence of all bases in the human genome. Microbes and microbiological techniques have contributed to this work.
Genomics
28
Over 100 bacterial genomes have been sequenced completely. A few have two instead of one chromosome.
Genomics
29
— has been at the forefront of research in medicine and biology, and microorganisms continue to play a critical role in genetic engineering and gene therapy.
Microbiology
30
— viruses may be able to cure diseases, and help ensure food safety.
Bacteriophage
31
Both — and — have membranes that define the bounds of the living cell, and both contain genetic information stored in DNA.
Prokaryotic and eukaryotic cells
32
they lack a defined nucleus and membrane-enclosed organelles (except for a few simple membrane-covered bodies in certain types of prokaryotes).
Prokaryotic cells
33
they have a defined nucleus and membrane-enclosed organelles
Eukaryotic cells
34
All — are classified in either the domain Archaea or the domain Bacteria.
Prokaryotes
35
— are the smallest living organisms.
typically ranging from 0.5 to 2.0 μm in diameter.
Prokaryotes
36
For comparison, a human red blood cell has a diameter of about —
7.5 μm
37
Many cells are not— so diameter is not always the best measure of size.
spherical in shape
38
Some spiral bacteria have larger —
Diameters
39
some — can be as long as 60 μm.
cyanobacteria
40
Bacteria typically come in three basic shapes:
spherical, rodlike, and spiral
41
A spherical bacterium is called a —
coccus (plural: cocci).
42
A rodlike bacterium is called a
—
bacillus (plural: bacilli).
43
Some bacteria, called — are short rods intermediate between cocci and bacilli.
coccobacilli
44
comma-shaped.
Vibrio
45
— rigid, wavy-shaped.
Spirillum (plural: spirilla):
46
— corkscrew-shaped.
Spirochete
47
Some bacteria have unique shapes such as —
Spindle- shaped or irregular, lobed shapes
48
— were discovered in 1981, found in the Red Sea, measuring 2 to 4 μm on a side, and sometimes forming waffle-like sheets.
Square bacteria
49
— were discovered in 1986.
Triangular bacteria
50
— refers to bacteria that vary widely in form within a single culture. These groupings form when cells divide without separating.
Pleomorphism
51
— can divide in one or more planes or randomly
Cocci
52
Division in — produces cells in pairs (prefix diplo-) or chains (prefix strepto-).
One plane
53
Division in — produces cells in tetrads (four cells arranged in a cube).
two planes
54
Division in — produces sarcinae (eight cells arranged in a cube)
three planes
55
— produces grapelike clusters (prefix staphylo-).
Random division
56
— divide in only one plane but can form cells connected end-to-end (like train cars) or side-by-side.
Bacilli
57
— do not generally group together in specific arrangements.
Spiral bacteria
58
— divide by binary fission, where new cell wall material grows, and the cell pinches in half.
Prokaryotes
59
Inside the cell, the — with one copy going to each daughter cell.
chromosome duplicates
60
The rigid cell wall outside the cell membrane is composed mainly of the —
polymer peptidoglycan
61
The — lies outside the cell membrane in nearly all bacteria.
semirigid cell wall
62
The cell walls performs two important functions:
• Maintains the characteristic shape of the cell.
• Prevents the cell from bursting when fluids flow into the cell by osmosis.
63
If the cell wall is digested away by—, the cell becomes spherical in shape.
enzymes
64
The cell wall surrounds the— but is usually extremely porous.
cell membrane
65
The cell wall DOES NOT play a major role in regulating the entry of materials into the cell.
True or False
True
66
Cell walls DO NOT differ in composition and structure.
True and False
False
67
In ____ bacteria, the
cell wall consists of a thick, dense layer of peptidoglycan, with teichoic acid
in it.
Gram-positive
68
In _____ bacteria, the cell wall has a thin layer of peptidoglycan,
separated from the cytoplasmic membrane by the periplasmic space and enclosed by an outer membrane made ______
Gram-negative, lipopolysaccharide, or endotoxin.
69
Some bacterial cell walls are damaged by ______
penicillin and lysozyme.
70
In ______ the cell wall consists mainly of lipids, some of which are
true waxes, and some of which are glycolipids.
acid-fast bacteria
71
_____ is the most important component of the
bacterial cell wall.
Peptidoglycan (also called murein)
72
Components of Cell Wall forms a large, covalently linked polymer resembling multiple layers of ______
chain-link fence
73
Gram-positive bacteria can have up to _______
40 layers of peptidoglycan.
74
Composed of alternating molecules of _____
N-acetylglucosamine (GluNAc) and
N-acetylmuramic acid (MurNAc).
75
Molecules are cross-linked by ______ which contain amino acids.
tetrapeptides
76
In ______ the third amino acid is usually lysine
Gram-positive bacteria
77
in Gram-
________ it is diaminopimelic acid.
negative bacteria,
78
Some amino acids are _____ making them resistant to breakdown
by most organisms.
stereoisomers
79
_____ is found in Gram-positive bacteria cell walls.
Teichoic acid
80
Teichoic Acid is MADE of glycerol, phosphates, and ribitol (a sugar alcohol).
True or False
True
81
Techoic Acid Forms polymers up to ____ long, extending beyond the cell wall and it Likely functions as attachment sites for bacteriophages and helps in ion
movement.
30 units
82
Outer membrane is present mainly in_____
Gram-negative bacteria.
83
It is a bilayer membrane attached to the peptidoglycan via lipoproteins.
Outer membrane
84
Acts as a coarse sieve, controlling the movement of certain proteins but
offering limited regulation of other substances.
Outer membrane
85
Contains ______ which serves as an endotoxin and helps
identify different Gram-negative bacteria.
Lipopolysaccharide (LPS),
86
_____ form channels through the outer membrane.
Gram-negative bacteria are less sensitive to penicillin due to the outer
membrane’s inhibition of its entry.
Porins
87
Gram-negative bacteria are ______ to penicillin due to the outer
membrane’s inhibition of its entry.
less sensitive
88
______ are released when bacteria die, making late-stage antibiotics
potentially dangerous.
Endotoxins
89
It is an active site of metabolism, breaking down harmful substances and transporting nutrients.
Periplasmic space
89
_____ is found in Gram-negative bacteria between the cell
membrane and cell wall.
Periplasmic space
90
Contains peptidoglycan, digestive enzymes, and transport proteins.
Periplasmic space
91
Gram-positive bacteria have a ___, but no well-defined periplasmic
space where metabolic digestion and cell wall construction occur.
periplasm
92
Have a thick peptidoglycan layer (20 to 80 nm thick).
Gram-Positive bacteria
93
______ of the cell wall is composed of peptidoglycan.
60-90%
94
Retain crystal violet-iodine dye in the cytoplasm during _____
staining.
95
Lack an outer membrane and periplasmic space.
Gram-Positive bacteria
96
If the peptidoglycan is digested, they become _____ cells with only a
cell membrane.
protoplasts
97
Gram- positive bacteria is SUSCEPTIBLE to becoming Gram-variable or Gram-negative with age or
damage.
true or false
true
98
_____ are released into the environment, where they may become diluted and ineffective.
Digestive enzymes
99
Have a thinner but more complex cell wall.
10-20% of the cell wall is peptidoglycan; the rest consists of polysaccharides, proteins, and lipids.
Gram-negative bacteria
100
Contain an outer membrane and periplasmic space.
Toxins and enzymes remain concentrated in the periplasmic space, aiding in defense.
Gram-negative bacteria
101
If the cell wall of Gram-negative bacteria is digested, they become ______
spheroplasts (retain both cell
membrane and most of the outer membrane).
102
Do not retain crystal violet-iodine dye due to thin walls and high levels of lipoproteins and lipopolysaccharides.
Gram-negative bacteria
103
Have a thick cell wall with approximately 60% lipid and much less peptidoglycan.
Acid-fast bacteria
104
In the acid-fast stain, _____ binds to the cytoplasm and resists removal by an acid-alcohol mixture.
carbolfuchsin
105
The ____ make these bacteria impermeable to most stains, acids, and alkalis.
lipids
106
Slow-growing because the lipids impede nutrient entry, requiring significant
energy for lipid synthesis.
Acid-fast bacteria
107
____ can be stained by the Gram stain method and appear
Gram-positive.
Acid-fast bacteria
108
________ digests peptidoglycan, helping prevent bacterial entry and infections.
Lysozyme (found in tears and other secretions)
108
_____ blocks the final stages of peptidoglycan synthesis, causing cell death during division.
Penicillin
109
-Lack a cell wall.
-Protected from osmotic swelling and bursting by a strengthened cell membrane containing sterols.
-Sterols are typical of eukaryotes and rarely found in prokaryotes.
-Despite membrane protection, mycoplasmas often require special media to grow.
-Without a rigid wall, they exhibit pleomorphism, forming slender, branched
filaments and varying in shape.
Mycoplasma bacteria:
110
- Bacteria that normally have a cell wall but lose their ability to form it.
-Named after the Lister Institute, where they were discovered.
- Loss of the cell wall may occur naturally or be induced by chemical
treatment.
L-forms
111
Some antibiotics that target cell wall synthesis may leave a few bacteria alive as L-forms, which CANNOT revert to walled forms and regrow after treatment stops.
true or false
False
111
may play a role in chronic or recurrent diseases.
L-forms
112
- Some species entirely lack cell walls.
- Others have unusual walls made of polysaccharides or proteins but lack peptidoglycan.
- Instead, they possess pseudomurein, a compound similar to
peptidoglycan.
Archaea:
112
The cell membrane has a _______ with phospholipids forming
a bilayer and proteins interspersed in a mosaic pattern.
fluid-mosaic structure
113
The main function of the cell membrane is to _______ of materials into and out of cells.
regulate the movement
114
_____ also perform functions usually carried out by organelles of eukaryotic cells.
Bacterial cell membranes
114
________ forms the boundary between the cell
and its environment.
Cell membrane (plasma membrane)
114
The cell membrane is NOT dynamic and constantly changing, unlike the more static cell wall.
true or false
False
115
Consists mainly of _______ like membranes in all cells.
phospholipids and proteins
116
Phospholipids form a ______
bilayer:
117
______ ends are hydrophobic and form a barrier.
Fatty acid
118
Phosphate ends are ______ and interact with water.
hydrophilic
119
Proteins are INTERPERSED among lipids
true or false
true
120
Some protein DO NOT extend through the membrane to form pores or channels for material transport.
True or false
false
121
Proteins on the ________ can help identify the organism.
outer surface
122
Inner surface proteins are often _____
enzymes.
123
Some bacteria, like mycoplasmas, include STEROLS for membrane rigidity.
true or false
true
123
Cell membranes are dynamic, with lipids and proteins changing positions.
true or false
true
124
7 Cell membrane functions
- Regulates movement of materials in and out of the cell.
- Synthesizes cell wall components.
- Assists in DNA replication.
- Secretes proteins.
- Performs respiration and ATP energy capture.
- Contains bases for flagella movement.
- Responds to chemical substances in the environment.
125
Bacteria contain a variety of inclusions, including ______ that store glycogen or other substances and vesicles filled with gas or iron compounds
(magnetosomes).
granules
126
The CORE of an endospore
contains living material and is surrounded by a cortex, spore coat, and exosporium.
true or false
True
126
Some bacteria DO NOT form resistant endospores.
true or false
false
127
Internal structures in bacterial cells includes:
ribosomes, a nucleoid, vacuoles, and sometimes endospores.
128
the semifluid substance inside the cell membrane.
cytoplasm
129
Cytoplasm is Composed of_______ water and one-fifth dissolved substances, including enzymes, proteins, carbohydrates, lipids, and inorganic ions.
four-fifths
130
Lacks the movement process known as ______- which is present in eukaryotic cytoplasm.
cytoplasm
130
Site of many chemical reactions (both anabolic and catabolic).
Cytoplasm
131
______ which consist of RNA and protein, serve as sites for protein synthesis.
Ribosomes
132
Consist of RNA and protein, abundant in the cytoplasm.
Ribosome
133
Often grouped in long chains called polyribosomes.
Bacterial ribosomes have a sedimentation rate of 70S (subunits: 30S and 50S), smaller than eukaryotic ribosomes (80S).
ribosome
134
The ______ usually includes just one, large, circular chromosome but can have two or three, some of which may be linear in shape, and which contain the
prokaryotic cell’s DNA and some RNA and protein.
nuclear region
135
Usually contains one large, circular chromosome, but some bacteria (e.g., Rhodobacter sphaeroides, Vibrio cholerae) have two circular chromosomes.
nuclear region
136
Lacks a nuclear membrane, unlike eukaryotes.
nuclear region
137
Consists mainly of DNA, with some associated RNA and proteins.
nuclear region
138
May also contain _______ (small circular DNA molecules), which carry supplementary genetic information.
plasmids
139
Some bacteria have _______ (e.g., Agrobacterium tumefaciens).
linear chromosomes
140
________ contain pigments for capturing light energy for sugar synthesis.
Chromatophores
140
Photosynthetic bacteria and cyanobacteria have internal membrane systems called ______
chromatophores.
141
________ have internal membranes that house enzymes for energy derivation from nitrogen compound oxidation.
Nitrifying bacteria
142
Polyphosphate granules, also called________
display different color intensities when stained.
volutin or metachromatic granules,
143
________ are large infoldings of the cell membrane, now considered artifacts
created by specimen preparation.
Mesosomes
144
_____ contain densely packed substances such as glycogen (energy) and polyphosphate (phosphate supply for metabolism).
Granules
145
Some bacteria contain _______ as a reserve.
sulfur granules
146
_______ are membrane-enclosed structures, some used for gas storage to regulate floating in aquatic photosynthetic bacteria.
Vesicles (vacuoles)
147
Other vesicles contain _________ a lipid used as an energy store and carbon source.
poly-β-hydroxybutyrate,
148
_____ are vesicles containing iron that help bacteria orient to
magnetic fields.
Magnetosomes
149
______ are resting stages produced by bacteria like Bacillus and Clostridium to survive adverse conditions.
Endospores
150
Endospores are NOT for reproduction but survival, unlike fungal spores.
true or false
true
151
Endospores are RESISTANT to heat, drying, acids, bases, disinfectants, and radiation.
true or false
true
152
Endospores are COMPOSED of a core, cortex, spore coat, and sometimes an exosporium.
true or false
true
153
______ Contain dipicolinic acid and calcium ions contributing to heat resistance.
endospores
154
Germinate when conditions become favorable, returning to vegetative cell form.
endospores
154
Can remain dormant for thousands of years and withstand extreme conditions
(e.g., hours of boiling).
endospores
155
Difficult to stain and resistant to sterilization, requiring special methods.
endospores
156
exhibit chemotaxis
(movement toward attractants and away from repellents)
157
The _______ includes all polysaccharides external to a bacterial cell wall.
glycocalyx
157
Some bacteria have _______ Conjugation pili allow exchange of DNA, whereas attachment pili (fimbriae) help bacteria adhere to surfaces.
pili
157
phototaxis
(movement toward or away from light).
158
______ prevent host cells from destroying a bacterium; capsules of any species of bacteria have a specific chemical composition.
Capsules
159
_______ protect bacterial cells from drying, trap nutrients, and sometimes
bind cells together, as in dental plaque.
Slime layers
160
_______ have one or more flagella, which propel the cell by the action of
rings in their basal body.
Motile bacteria
161
Flagella HAVE Helical appendages for motility.
true or false
true
162
Single polar flagellum.
Monotrichous
163
One flagellum at each end.
Amphitrichous
164
Multiple flagella at one or both ends.
Lophotrichous:
165
Flagella _____ for movement, enabling runs (straight movement) and tumbles (random turns).
rotate
165
Flagella all over the surface.
Peritrichous
166
Composed of flagellin protein and connected to the cell membrane by a complex basal body.
external structure
166
Movement in response to chemical gradients (toward nutrients or
away from harmful substances).
Chemotaxis
167
Movement toward or away from light.
Phototaxis
168
- Found in spirochetes, located between the outer sheath and cell wall.
- Twisting action of filaments causes the spirochete to rotate like a corkscrew.
Axial Filaments
169
Small, hollow projections for attachment, not for movement.
pili
170
Two types of external structure
Conjugation pili (sex pili)
Attachment pili (fimbriae)
171
Aid in bacterial adhesion to surfaces, contributing
to pathogenicity and biofilm formation.
Attachment pili (fimbriae):
171
Facilitate DNA transfer between cells (conjugation).
Conjugation pili (sex pili):
172
External polysaccharide layer, varies in thickness from thin slime layers to thick capsules.
Glycocalyx
173
- Protective, gel-like layer.
- Helps bacteria evade immune defenses like phagocytosis.
- Important in virulence.
capsules
174
- Loosely bound, thin layers.
- Protect against drying, trap nutrients, and enable adherence to surfaces.
- Important in biofilm formation, such as dental plaque.
Slime layers
175
______ which are generally larger and more complex than prokaryotic
cells, are the basic structural unit of microscopic and macroscopic organisms of
the kingdoms Protista, Plantae, Fungi, and Animalia.
Eukaryotic cells
176
Plasma membranes of eukaryotic cells are almost identical to those of prokaryotic
cells, except that they contain______
sterols
177
____ are characterized by the presence of a membrane-enclosed cell
nucleus, with a nuclear envelope, nucleoplasm, nucleoli, and chromosomes
(typically paired) that contain DNA and proteins called histones.
Eukaryotic cells
178
The function of eukaryotic plasma membranes, however, is LIMITED primarily to regulating movement of substances into and out of cells.
true or false
true
178
Contain ____ for added rigidity, helping withstand stress due to lower surface-to-
volume ratio.
sterols
179
Eukaryotic membranes have a greater variety of ______.
lipids
180
lacks respiratory enzymes for ATP synthesis (mitochondria take over this function)..
eukaryotic cell membrane
181
Eukaryotic Cell Membrane is LESS VERSATILE than prokaryotic membranes;
true or false
true
182
- Smaller proportion of eukaryotic cells compared to prokaryotes.
- Contains water, dissolved substances, and elements of the cytoskeleton (fibrous
network providing shape and support).
Eukaryotic Cytoplasm
183
- Enclosed by a nuclear envelope, contains nucleoplasm, nucleoli, and chromosomes.
- Nuclear pores allow RNA to exit the nucleus for protein synthesis.
- Nucleoli serve as sites for ribosome assembly.
- Contains paired chromosomes with DNA and histones.
- Divides via mitosis (diploid cells) and meiosis (haploid cells in sexual reproduction).
Eukaryotic Cell Nucleus
184
Powerhouses of the cell, responsible for ATP production.
mitochondria
185
Contains an outer and inner membrane; inner membrane has folds called _____
cristae
186
Contain outer and inner membranes, as well as thylakoids for capturing light energy via
chlorophyll.
Chloroplasts (in photosynthetic cells)
187
Mitochondria can replicate INDEPENDENTLY and contain their own DNA.
true or false
true
188
chloroplasts DO NOT HAVE their own DNA and replicate independently.
true or false
false
189
Larger than those in prokaryotes, with an 80S sedimentation rate (subunits 60S and
40S).
Ribosomes
190
Provide sites for protein synthesis.
ribosomes
191
Network of membranes with smooth and rough regions.
Endoplasmic Reticulum (ER)
192
____ synthesizes lipids.
Smooth ER
193
_____ has ribosomes and helps in protein synthesis.
Rough ER
194
- Receives, stores, and modifies substances from the ER.
- Packages substances into vesicles for secretion or membrane formation.
Golgi Apparatus:
195
Small organelles containing digestive enzymes, involved in breaking down ingested substances or bacteria.
Eukaryotic Lysosomes
196
Organelles that oxidize substances (amino acids in animals, fats in plants).
Peroxisomes
197
Convert hydrogen peroxide to water.
Peroxisomes
198
Store materials like starch, glycogen, or fats.
In plants, they maintain rigidity; loss of water in vacuoles leads to wilting.
Vacuoles
199
Network of microtubules and microfilaments providing structure and aiding in movement and cell division.
Cytoskeleton
200
- Shorter and more numerous than flagella, with the same 9+2 microtubule arrangement.
Cilia
201
-Larger and more complex than prokaryotic flagella.
- Composed of a 9+2 arrangement of microtubules made of tubulin.
Flagella
202
- Temporary cytoplasmic projections used for amoeboid movement.
Pseudopodia (False Feet)
203
Provide rigidity and protect cells from bursting due to water intake.
Cell Walls
204
_____ made of cellulose or other polysaccharides.
Algal cell walls:
205
_______ flexible pellicles instead of rigid cell walls.
Protozoan coverings
205
_______ composed of cellulose, chitin, or both.
Fungal cell walls
206
______ results from interaction between actin and myosin filaments, similar to those present in our own muscles
Amoeboid movement
207
Involves cytoplasmic streaming and is a slow movement process.
Pseudopodia (False Feet)
208
-Move in a whip-like motion, powered by ATP hydrolysis.
Flagella
209
Propel fluids and particles past the cell surface (important in the human respiratory
tract).
Cillia
210
Beat in coordinated strokes, creating waves that allow rapid movements
Cillia
211
Found mainly in protozoa, algae, and human sperm cells.
Flagella
212
- Found in cells without walls, like amoebas and white blood cells.
Pseudopodia (False Feet)
