Exam 1 Material Flashcards
(349 cards)
1
Q
How are bacteria and archaea different from eukaryotes?
A
1) the way their DNA is packaged; bacteria lack nucleus and histones
2) the makeup of their cell wall; most bacteria have peptidoglycan and archaea have pseudomurein
3) their internal structures; archaea and most bacteria lack of membrane-bound organelles
2
Q
What structures are found in all bacteria?
A
cell membrane, chromosomes, ribosomes, cytoplasm
3
Q
What structures are found in some, but not all bacteria?
A
cytoskeleton, pilus, glycocalyx, inclusion/granule, microcompartments, plasmid, flagellum
4
Q
cell membrane
A
thin sheet of lipid and protein that surrounds the cytoplasm and controls the flow of materials in and out of the cell
5
Q
bacterial chromosome
A
composed of condensed DNA molecules; dna directs all genetics and heredity of the cell
6
Q
ribosomes
A
tiny particles composed of protein and RNA that are the sites of protein synthesis
7
Q
cytoplasm
A
water-based solution filling the entire cell
8
Q
cytoskeleton
A
long fibers that encircle the cell just inside the cytoplasmic membrane and contribute to the shape of the cell
9
Q
pilus
A
appendage used for drawing another bacterium close in order to transfer dna
10
Q
What appendage is used to transfer DNA from one bacterium to another?
A
Pilus
11
Q
glycocalyx
A
coating or layer of molecules external to the cell wall serves protective, adhesive, and receptor functions
12
Q
inclusion/granule
A
stored nutrients deposited into dense crystals
13
Q
microcompartments
A
protein-coated packets used to localize enzymes and other proteins in the cytoplasm
14
Q
plasmid
A
double-stranded DNA containing extra genes
15
Q
flagellum
A
specialized appendage, movement pushes the cell foreward and provides motility
16
Q
What is the average size of bacteria?
A
1 micrometer
17
Q
What is the circumference of cocci?
A
1 micrometer
18
Q
What is the average length and width of rods?
A
Length:2 micrometers; width: 1 micrometer
19
Q
mycoplasma pneumoniae
A
respiratory infections
20
Q
spirilla
A
a rigid, helix, twisted twice or more along its axis like a corkscrew
21
Q
spirochetes
A
a spiral cell that contains periplasmic flagella
22
Q
How can cocci bacteria be arranged?
A
single, diplococci, tetrads, staphlococci/micrococci, streptococci or sarcina
23
Q
diplococci
A
pairs of cocci
24
Q
tetrads
A
groups of four
25
staphlococci
irregular clusters
26
streptococci
chains
27
sarcina
cubical packet of eight, sixteen, or more cells
28
What are the arrangements of bacillus bacteria?
single, diplobacilli, streptobacilli, palisades
29
palisades
cells of a chain remain partially attached by a small hinge region at the ends
30
What is an example of a structure possessed by some but not all prokaryotes?
Flagella
31
What appendages are used for motility?
Flagella and axial filaments(spirochetes)
32
What appendages are used for attachment/adhesion?
Fimbrae, pili, and nanotubes/nanowires
33
monotrichous
one flagella at one end of cell
34
peritrichous
multiple flagella all covering random sites on the cell
35
amphitrichous
multiple flagella at both ends of cell
36
lophotrichous
multiple flagella at one end of cell
37
chemotaxis
movement of bacteria in response to chemical signals
38
positive chemotaxis
movement toward favorable chemical stimulus
39
negative chemotaxis
movement away from a repellant
40
Which chemotaxis moves towards favorable stimulus?
positive chemotaxis
41
Which chemotaxis moves away from a repellant?
negative chemotaxis
42
Run
rotation of flagellum counterclockwise, resulting in smooth linear direction
43
Tumble
reversal of the direction of the flagellum, causing the cell to stop and change course
44
Spirochetes
possess an unusual, wriggly mode of locomotion due to periplasmic flagella
45
borelia burgdorferi
primary causative agent of lyme disease
46
treponema pallidum
causative agent of syphilis
47
Fimbria/fimbrae
small, bristle-like fibers sprouting off the surface of many bacterial cells
48
What do fimbrae aid in?
Allow tight adhesion between fimbrae and epithelial cells, allowing bacteria to colonize and infect host tissues
49
Pilus
used in conjugation between bacterial cells
50
What appendage is highly characterized in gram-negative bacteria?
Pilus
51
What do type IV pilus do?
Type IV pilus can transfer genetic material, act like fimbrae & assist in attachment
52
Nanotubes
very thin, long, tubular extensions of the cytoplasmic membrane
53
What purpose do nanotubes serve?
Used as channels to transfer amino acids or to harvest energy
Communicate with other bacteria and archaea
54
S layer
single layers of thousands of copies of a single protein linked together
55
When is the s layer produced?
When bacteria are in a hostile environment
56
Glycocalyx
coating of repeating polysaccharide or glycoprotein unitsi
57
Slime layer
loose, protects against loss of water and nutrients
58
Capsule
more tightly bound, denser, thicker
59
What does the capsule protect against?
protects against phagocytosis by white blood cells
60
Biofilm
responsible for persistent colonization of plastic catheters, IUDS, metal pacemakers, and other implanted medical devices
61
What is an example of biofilm?
plaque on teeth protects bacteria from becoming dislodged
62
Cell envelope
composed of 2 or 3 layers that each perform a distinct function, but together act as a single protective unit
63
What parts make up the cell envelope?
outer membrane, cell wall, and cytoplasmic membrane
64
Cytoplasmic membrane
a phospholipid bilayer with embedded proteins
65
What occurs at the cytoplasmic membrane?
energy reactions, nutrient processing, synthesis
66
What is the purpose of the cytoplasmic membrane?
regulates transport of nutrients and wastes
67
Selectively permeable
special carrier mechanisms for passage of most molecules
68
Cell wall
helps determine the shape of bacterium, provides structural support to keep bacterium from bursting when undergoing change in osmotic pressure
69
How do drugs work at treating infections?
drugs target cell wall, disrupting its integrity and causing cell lysis
70
Cell lysis
disintegration or rupture of cell
71
Peptidoglycan
helps cell wall gain relative rigidity
72
What is the peptidoglycan layer composed of?
compound composed of a repeating framework of long glycan(sugar) chains cross-linked by short peptide (protein) fragments
73
Gram-positive cell wall
thick, homogeneous sheet of peptidoglycan
20 to 80 mm in thickness
74
What acids is the gram-positive cell wall composed of?
teichoic acid and lipoteichoic acid
75
What function do teichoic acid and lipoteichoic acid have?
cell wall maintenance and enlargement during cell divison
76
Gram-negative cell wall
single, thin sheet of peptidoglycan
77
What does the thinness of the gram-negative cell wall cause?
greater flexibility and sensitivity to lysis
78
What is the difference between gram-negative outer membrane and other membranes?
gram-negative cell membrane contains specialized polysaccharides and proteins
79
What types of molecules pass through the outer membrane of gram-negative cell wall?
Small molecules i.e. glucose and monosaccharides
80
Porin proteins
special water-filled channels that only allow certain small molecules to penetrate, water soluble compounds
not found in cytoplasmic membrane
81
lipoproteins
connects outer membrane to peptidoglycan layer
82
lipopolysaccharides
stabilizes the outer membrane, contributes to the negative charge of outer membrane
83
What function do lipopolysaccharides have in bacteria?
acts as permeability barrier, helps protect bacteria from host defense
84
What does the O-antigen of lipopolysaccharides do?
signaling and as a receptor; elicits an immune response by infected host
85
endotoxin
lipid a portion; stimulates fever and shock reaction in gram-negative infections
86
What are examples of gram-negative infections that could induce endotoxins?
Meningitis and typhoid fever
87
What happens if LPS or lipid a enters the bloodstream?
A form of shock develops for which there is no direct treatment
88
What does the extra barrier in gram-negative bacteria do?
it is resistant to certain microbial chemicals and is more difficult to inhibit or kill than gram-positive bacteria
89
How do alcohol-based compounds affect cells?
alcohol-based compounds dissolve lipids in the outer membrane and therefore damage the cell
90
What is an example of alcohol-based compounds being used?
alcohol swabs used to clean the skin before certain medical procedures
91
What is the difference in treatment between gram-positive infections and gram-negative infections?
Gram-negative infections require drugs that can cross the outer membrane
92
What are the steps in a gram stain?
1) crystal violet; CV is added to cells in smear and changes/stains cells purple
2) gram's iodine
93
What are the steps in a gram stain?
1) crystal violet; CV is added to cells in smear and changes/stains cells purple
2) gram's iodine; stabilizer causes the dye to form large complexes in the peptidoglycan layer. thicker gram-positive cell walls are more firmly able to trap large complexes
3) alcohol; alcohol dissolves lipids in outer membrane. removes dye from peptidoglycan layer in gram-negative cells
4) safranin; gram-neg bacteria become present due to colorlessness
94
examples of mycrobacterium
tuberculosis and leprosy
95
What is a key feature of mycobacterium and norcardia when gram stained?
Stain gram-positive, but bulk of cell wall is comprised of unique lipids
96
mycolic acid
fatty chains found in cell walls of acid-fast bacteria; contributes to pathogenecity of bacteria
*makes bacteria highly resistant to certain chemicals and dyes
97
What is different about the cell walls of archaea?
some cell walls are composed of entirely polysaccharides while others have cell walls made of pure protein
98
Do archaea contain peptidoglycan?
archaea lack true peptidoglycan structure, some may not have cell wall
99
Mycoplasmas
naturally lack a cell wall
100
Why are mycoplasmas resistant to certain antibiotics?
due to lack of cell wall, naturally resistant to antibiotics that target the cell wall
101
hopanoids
cholesterol analog in cell membrane that stabilize the cell against lysis
102
L forms
some naturally have a cell wall but lose it during part of their life cycle; plays a role in persistent infections; resistant to antibiotics
103
cytoplasm
70 to 80% water, complex mixture of sugars, amino acids, and salts
104
What is the purpose of the cytoplasm?
serves as a pool for building blocks for cell synthesis or sources of energy
105
Where is the heredity material of bacteria stored?
bacterial chromosomes
106
Where is DNA aggregated?
nucleoid
107
plamids
nonessential pieces of DNA
108
What do plasmids confer?
protective traits such as drug resistance and toxins and enzyme production
109
ribosomes
site of protein synthesis
110
What are ribosomes composed of?
rRNA and protein
111
How are ribosomes measured?
using the Svedberg unit, which corresponds to the rate of sedimentation when centrifuged
112
What is the small subunits measurement?
30S
113
What is the large subunits measurement?
50S
114
What is the large and small subunits measurement together?
70S
115
What is the measurement of an archaeal ribosome?
70S
116
What is the measurement of a eukaryotic ribosome?
80S
117
What are inclusion bodies used for?
food storage; pack gas into vesicles for buoyancy; store crystals of iron oxide with magnetic properties
118
bacterial microcompartments
outer shells made of protein, arranged geometrically
119
What do microcompartments contain?
concentrates CO2 and houses RubisCO
packed full of enzymes designed to work together in biochemical pathways
120
cytoskeleton
arranged in helical ribbons around the cell beneath cell membrane
contribute to cell shape
121
What is special about the cytoskeleton in noneukaryotic cells?
may be a potential target for antibiotic development
122
action homologue
MreB: many rods, helps determine cell shape?
123
Tubulin homologue:Fts2 protein
forms a ring that constricts during cell divison
124
bacterial endospores
dormant bodies
125
Where are the medically important species found in endospores?
genera Bacillus and Clostridia
126
vegetative cell
metabolically active
127
sporulation
induced by depletion of nutrients in the environment
128
What is special about endospores?
resist extremes of heat, drying, freezing, radiation, and chemicals that would kill vegetative cells
129
bacillus anthracis
agent of anthrax
130
clostridium tetani
cause of tetanus
131
clostridium perfringes
cause of gas gangrene
132
clostridium botulinum
cause of botulism
133
clostridium difficile
"c. diff" a serious gastrointestinal disease
134
What domain is archaea more closely related to?
Eukarya; lack peptidoglycan
135
Why is archaea more closely related to eukarya than bacteria?
lack peptidoglycan; histone proteins; protein synthesis and ribosomal subunit structures are similar; share rRNA sequences not found in bacteria
136
extremophiles
some live at extremely high or low temperatures, some need extremely high salt or acid concentrations to survive, some live on sulfur, some produce methane
137
Bergey's manual of Systemic Bacteriology
a comprehensive view of bacterial and archael relatedness; based on rRNA sequencing
138
Bergey's manual of Determinative Bacteriology
based entirely on phenotypic characteristics; categorizes organisms based on traits commonly assessed in clinical, teaching, and research labs such as seen on in a microscope or metabolic capabilities
139
bacterial species
a collection of bacterial cells, all of which share an overall similar pattern of traits; should share at least 70 to 80% of their genes
140
subspecies/strain/type
bacteria of same species that have differing characteristics
141
serotype
representatives of a species that stimulate a distinct pattern of antibody responses because of a unique surface molecules
142
When did the first eukaryotic cells appear?
about 2.5 billion years ago
143
What did bacteria, archaea, and eukarya all evolve from?
the Last Common Ancestor
144
What was true about the first primitive eukaryotes?
they were likely single celled and independent
145
What happened to cells over time?
began aggregating and forming colonies
146
What do the cells in colonies do?
the cells in colonies became specialized to perform a specific function
147
What happened to complex multicellular organisms?
they lost the ability to survive seperately from the intact colony about 1.5 billion years ago
148
What genus is always unicellular?
protozoa
149
What genus are either unicellular or multicellular?
fungi and algae
150
What genus are always multicellular?
nelminths(have unicellular egg)
151
How many species of protozoa are there?
12,000 single-celled creatures
152
What do protozoa do?
most are harmless, free-living inhabitants of water and soil
important predators of bacteria
153
How often do protozoa cause infections in humans?
few species are pathogens responsible for hundreds of millions of infections each year
154
What are protozoans made up of?
single cells containing all of the major eukaryotic organelles except chloroplasts
155
What two parts does the cytoplasm of protozoa divide into?
ectoplasm and endoplasm
156
ectoplasm
clear outer layer involved in locomotion, feeding, and protection
157
endoplasm
granular inner region housing the nucleus, mitochondria, and food and contractile vacuoles
158
contractile vacuoles
common in protists; contractile vacuoles help maintain osmoregulation
159
steps of osmoregulation
1) water enters due to osmosis
2) excess water enters contractile vacuole
3) contractile vacuole swells
4) contractile vacuole moves to edge of cell
5) contractile vacuole bursts and expels water
6) cycle is repeated
160
phagocytic vacuoles
allow some protists to ingest food
engulfment
digestion of prey in food vacuole
161
How do protozoan move?
move via pseudopods, cilia, or flagella
162
What does the cell membrane of protozoan do?
regulates food, wastes, and secretions
163
ciliates cell shape
remain constant
164
amoebas cell shape
changes constantly
165
What is the size of protozoans?
range from 3 to 300 micrometers
166
How do protozoan eat?
some have special feeding structures, some absorb food directly through the cell membrane
167
How do pathogenic species eat?
some may live on fluids of their host or actively feed on tissues
168
What are the predominant habitats of protozoa?
fresh and marine water, soil, plants, and animals
169
trophozoite
motile feeding stage requiring ample food and moisture to stay alive
170
cyst
dormant, resting stage, when conditions in the environment become unfavorable
171
What are cysts resistant to?
heat, drying and chemicals
172
How can cysts be dispersed?
by air currents; important factor in the spread of disease
173
What is the life cycle of protozoa?
1) trophozoite active feeding stage
2) cells round up, loses motility
3)mature cyst dormant resting stage
4)cyst wall breaks open
5)trophozoite is reactivated
174
What phases do some protozoan groups exist in?
Trophozoite phase
175
What stages do many protozoa alternate between?
trophozoite and cyst stage depending on habitat
176
trichomonas vaginalis
common STD, does not form cysts and must be transmitted by intimate contact
177
entamoeba histolytica/giardia lambia
form cysts and are readily transmitted by contaminated water and foods
178
How do protozoa reproduce?
all protozoa reproduce by simple, asexual mitotic cell division
179
How do the ciliates participate in conjugation?
two cells fuse and exchange micronuclei
180
What are some benefits of fungi?
play an essential role in decomposing organic matter and returning minerals to soil
able to breakdown complex carbon complexes
form stable associations with plant roots and increase their ability to absorb water and nutrients
181
What role do fungi play in healthcare?
engineered to produce large quantities of antibiotics, alcohol, organic acids and vitamins
182
hyphae
long, threadlike cells found in bodies of filamentous fungi
183
yeasts
round to oval shape, asexual reproduction, budding
184
pseudohypha
chains of yeast cells
185
What are yeasts?
wild saprotrophic, domesticated, or pathogenic species
186
How many species of yeast are there?
1500 species
187
Where are yeast found?
wild saprotrophic species in soils, on plant surfaces, sugary mediums(nectar, fruits)
188
What are domesticated species of yeast used for?
used to make breads, beer, wine, chocolate
189
What is the morphology of fungi?
cells of most microscopic fungi grow in loose associations of colonies
190
What do colonies of yeast look like?
much like bacteria; they have a soft, uniform texture and appearance
191
mycelium
the woven, intertwining mass of hyphae that makes up the body or colony of mold
192
septa
segments or cross walls found in most fungi that allow the flow of organelles and nutrients between adjacent environments
193
What do nonseptate hyphae look like?
one, long, continuous cell
194
absorptive nutrition
secretion of nutrients, extracellular digestion, absorption of solubilized small compounds, apical growth of hyphae
195
heterotrophic
acquire nutrients from a wide variety of organic substrates
196
saprobic
obtain nutrients from the remnants of dead plants and animals in soil or aquatic habitats
197
What conditions do fungi typically thrive in?
nutritionally poor or adverse environments, and those with high salt or sugar content
198
parasitic
organism that lives in or on another organism for the purpose of acquiring nutrients
199
Where do parasites grow?
on the bodies of living animals or plants causing harm
200
pathogens
cause disease in host
201
mutualistic
rely on partner organism for complex carbohydrates
rely on photosynthetic host for fixed carbon
202
spores
primary reproductive mode of fungi
can be dispersed through the environment by air, water, and living things
203
What are spores resistant to?
resistant to drying, heating, freezing, and chemicals
204
What are the two types of asexual mold spores?
sporangiospores and condidospores
205
How are sporangiospores formed?
formed by successive cleavages within a saclike head called sporangium, which is attached to a stalk, the sporangiospore
206
condidiospores
free spores not enclosed by a spore-bearing sac
207
How do condidiospores develop?
by successive mitotic divisons, the pinching off of the tip of a special fertile hypha or by the segmentation of a pre-existing vegetative hypha
208
aspergillus flavus
green conidia and produces a flatoxin, the most toxigenic cancer-causing compound found in nature
209
How many species of fungi can cause human disease?
about 300 species
210
How do spores affect AIDS patients?
harmless spores can cause opportunistic infections in AIDS patients
211
How do fungi affect allergies?
fungal cell walls give off substances that cause allergies
212
How do poisonous mushrooms affect human health?
toxins produced by poisonous mushrooms can induce neurological disturbances and death
213
What does aspergillus flavus produce?
produces a potentially lethal poison called aflatoxin to animals who eat contaminated grain
214
Where does aflatoxin accumulate?
the liver
215
How do fungi affect agriculture?
number of species are pathogenic to corn and grain
reduces crop production
can cause disease in domestic animals consuming contaminated feed crops
fungi rot fresh produce during shipping and storage
216
What do photosynthetic eukaryotes do?
strict aerobes, use photosystems I and II for oxygenic photosynthesis
217
chlorophyta
phototrophs have chlorophylls a & b, and carotenoid accessory pigments
218
Where is chlorophyta food stored?
starch in purenoids
219
What do chlorophyta cell walls have?
cellulose cell walls
220
chlamydomona
large chloroplast, conspicious pyrenoid, osmoregulation controlled by two small contractile vacuoles at flagella base
221
euglena
secondary endosymbiosis with green algae
commonly found in fresh water
222
Are euglena pathogenic?
non-pathogenic
223
How do euglena feed?
phagocytosis
224
diatoms
chlorophylls a and c
accessory pigments
two-piece cell wall of silica
important in global carbon cycling
biofuels
225
golden algae
chrysophytes
primarily unicellular marine and fresh water phototrophs
chlorophyll c
accessory pigment: fucoxanthin
226
dinoflagellates
large group found in marine plankton cause toxic blooms in seawater
nutritionally complex
chlorophyll a and c, beta-carotene, xanthophylls unique
227
chemoheterotrophs
absorb unique matter or engulf prey
228
How do dinoflagellates get carbon and energy?
can be combination of autotroph and heterotrophic
229
What occurs with Florida red tides?
red tide is normal October to November
increasing intensity
results in marine life death
100 manatees, dozen dolphins, 1000s of fish, 300 sea turtles
230
essential nutrient
any substance that must be provided to an organism
231
macronutrients
required in relatively large quantities and play principal roles in cell structure and metabolism
232
What are some examples of macronutrients?
carbon, hydrogen and oxygen
233
micronutrients
present in much smaller amounts and are involved in enzyme function and maintenance of protein structure
234
What are some examples of micronutrients?
manganese, zinc, and nickel
235
inorganic nutrients
an atom or simple molecule that contains a combination of atoms other than C and H
236
Where are inorganic nutrients found?
found in earth's crust, bodies of water, and the atmosphere
237
What are some examples of inorganic nutrients??
metals and their salts(magnesium sulfate, ferric nitrate, sodium phosphate)
gases(oxygen, CO2) and water
238
organic nutrients
contain carbon and hydrogen atoms and are usually the products of living things
239
What are some examples of organic nutrients?
methane
large polymers(carbohydrates, lipids, proteins, and nucleic acids)
240
What chemicals make up the cytoplasm?
water-70%
proteins
organic compounds: 97% of dry weight
elements CHONDS: 96% of dry weight
241
heterotroph
an organism that must obtain its carbon in an organic form
242
autotroph
an organism that uses inorganic CO2 as its carbon source
243
What is unique about autotrophs?
has the capacity to convert CO2 to organic compounds
not nutritionally dependent on other living things
244
phototroph
microbe that photosynthesizes
245
chemotroph
microbe that gets its energy from chemical compounds
246
photoautotroph
photosynthetic, produce organic molecules using CO2 that can be used by themselves and by heterotrophs
247
photosynthetic
converts sun's energy to chemical energy found in the bonds of organic molecules
248
chemoautotroph
chemoorganic molecules, lithoautotrophs
249
chemoorganic molecules
use organic compounds for energy and inorganic compounds as carbon source
250
lithoautotroph
rely totally on inorganic minerals and require neither sunlight nor organic nutrients
251
chemoheterotrophs
derive both carbon and energy from organic compounds
process those molecules through cellular respiration
252
saprobes
free-living organisms that feed on organic detritus from dead microbes
253
parasites
derive nutrients from the cells of tissues of a living host
254
pathogens
cause damage to tissues or even death
255
ectoparasites
live on the body
256
endoparasites
live in the organs and tissues
257
intracelluar parasites
live within cells
258
obligate parasites
unable to grow outside of a living host
259
What are examples of obligate parasites?
leprosy bacillus and syphillus spirochete
260
What is an example of passive transport?
simple diffusion and facilitated diffusion
261
simple diffusion
a fundamental property of atoms and molecules that exist in a state of random motion, require no energy
262
facilitated diffusion
molecules bind to specific receptor in membrane and is carried to other side, molecule specific, goes both directions, rate of transport is limited
263
What is an example of active transport?
carrier-mediated active transport
264
carrier-mediated active transport
atoms or molecules are pumped in and out of cell by specialized receptors
driven by ATP or proton motive force
265
active transport
transport of nutrients against the diffusion gradient or in the same direction as the natural gradient, but at a rate faster than by diffusion alone
266
What substances would be transported actively?
monosaccharides, amino acids, organic acids, phosphates, and metal ions
267
group translocation
chemically modifies molecule transported
energy-rich organic compound(not proton-motive force) drives transport
268
phosphotransferase system
PTS
used widely in faculative or strict anaerobic bacteria
269
What does the phosphotransferase system do?
transfer of phosphate, phosphorelay system
enzyme I and HPr are nonspecific cytoplasmic proteins
270
What is enzyme II?
a protein complex, specific for different sugars
271
What genus is PTS found in?
only found in bacteria
272
ABC systems
200+ different systems identified in prokaryotes for organic and inorganic compounds
273
ATP hydrolysis
provides energy and drives uptake of nutrients
274
transporter
solute-binding protein attaches to transporter-releases solute
275
iron transport by a siderophore and an ABC transport complex
minerals needed by the cell are often inaccessible in the environment outside the cell
iron is an important mineral nutrient, is mostly locked up in the inaccessible form:iron hydroxide
276
Eurkaryotes endocytosis
eating and drinking by cells
277
endocytosis
cell encloses the substance in its membrane
simultaneously forms a vacuole and engulfs the substance
278
phagocytosis
accomplished by amoebas and white blood cells
ingest whole cells or large solid matter
in animals, fuse with lysosomes
279
pinocytosis
ingestion of liquids such as oils or molecules in solution
fuses w endosomes
280
zone of intolerance
extreme low temperatures and extremely high temperatures
281
zone of physiological stress
slightly too cold, slightly too hot temperatures
282
optimum range temperature
middle temperature
283
extremophiles
harsh conditions, usually lethal
284
What happens at the optimum temperature?
promotes the fastest rate of growth and metabolism
285
psychophiles
optimum temperature below 15 celsius
capable of growth at 0 celsius
obligate w respect to cold and cannot grow above 20 celsius
286
What would happen if you put psychophiles in refrigerator temperatures?
cause them to grow rather than inhibiting them
287
What are the habitats of psychophilic bacteria, fungi, and algae?
lakes, rivers, snowfields, polar ice, and the deep ocean
288
Are psychophiles pathogenic?
rarely pathogenic
289
psychotrophs
grow slowly in the cold but have an optimum temperature between 15 and 30 celsius
290
What are examples of bacteria that can grow at refrigerator temperatures?
staphylococcus aureus and listeria monocytogenes are able to grow at refrigerator temperatures and cause food-borne illness
291
mesophiles
majority of medically significant microorganisms
grow at intermediate temperatures between 20 and 40 celsius
292
What is the temperature range of human pathogens as mesophiles?
30 and 40 celsius
293
thermoduric microbes
can survive short exposure to high temperatures but are normally mesophiles
common contaminants of heated or pasteurized foods
294
What are examples of heat-resistant endospore formers?
bacillus and clostridium
295
thermophiles
grow optimally at temperatures greater than 45 celsius
296
Where do thermophiles live?
live on soil and water associated with volcanic activity, compost piles, and in habitats directly exposed to the sun
297
What is the optimum temperature range for thermophiles?
45 to 80 celsius
298
What temperature do extreme thermophiles live at?
80 and 121 celsius
299
What gases influence microbial growth?
oxygen, and carbon dioxide
300
Which gas has the most impact on microbial growth?
oxygen
301
What three categories do microbes fall into regarding oxygen?
those that use oxygen and detoxify it
those than can neither use oxygen nor detoxify it
those that do not use oxygen but can detoxify it
302
How do microbes process oxygen?
as oxygen enters cellular respiration, it is transformed into several toxic products
303
singlet oxygen(O)
an extremely reactive molecule that can damage and destroy a cell by the oxidation of membrane lipids
304
superoxide ion(O2-)
highly reactive
305
hydrogen peroxide(H2O2)
toxic to cells and used as a disinfectant
306
hydroxyl radical(OH-)
also highly reactive
307
How do microbes protect themselves against damage from oxygen by-products?
most cells have developed enzymes that scavenge and neutralize reactive by-products
308
aerobes
can use gaseous oxygen in their metabolism and possess the enzymes needed to process toxic oxygen products
309
obligate aerobe
an organism that cannot grow without oxygen
310
microaerophiles
are harmed by normal atmospheric concentrations of oxygen but require a small amount of it in metabolism
311
facultative anaerobes
do not require oxygen for metabolism but use it when present
312
anaerobes
lack the metabolic enzyme systems for using oxygen in respiration
313
aerotolerant anaerobes
do not utilize oxygen but can survive and grow to a limited extent in its presence
314
Are aerotolerant anaerobes harmed by oxygen?
not harmed by oxygen because they possess alternate mechanisms for breaking down peroxide and superoxide
315
ph
defined as the degree of acidity or alkalinity of a solution
316
How is ph measured?
by ph scale, a series of numbers ranging from 0 to 14
317
What is the value of pure water?
7.0
318
If the ph value decreases toward 0, what is it considered?
acidic
319
If the ph value increases toward 14, what is it considered?
alkalinic
320
neutrophiles
the majority of organisms live or grow in habitats between 6 and 8(7)
321
acidophiles
organisms that thrive in acidic environments(0.5-~5.5)
322
euglena mutabilis
grows in acid pools between 0 and 1
323
thermoplasma
lives in coal piles at a ph of 1 or 2
324
picrophilus
thrives at a ph of 0.7 but can grow at a ph of 0
325
alkalinophiles
organisms that thrive in alkaline conditions(~8.5-12)
326
natronomonas
live in hot pools and soils up to ph 12
327
proteus
can create alkaline conditions to neutralize urine and colonize and infect the urinary system
328
binary fission
process where one cell becomes two
parent cell enlarges
duplicates its chromosome
starts to pull its cell envelope together to the center of the cell
329
steps in binary fission
1) a young cell
2) chromosome is replicated and new and old chromosomes move to different sides of the cell
3) protein band forms in the center of the cell
4)septum formation begins
5) when septum is complete, cells are considered divided. some detach, some remain attached
330
growth on a plate
each individual colony is a result of 1000s of binary fission events
331
generation time
the time required for a complete fission cycle, from parent cell to two daughter cells
332
generation
increases the population by a factor of two
333
What is needed for doubling to continue?
the environment remains favorable
334
length of generation time
a measure of the growth rate of an organism
335
What is the average generation time?
30 to 60 minutes
336
What are some of the shortest generation times?
10 to 12 minutes
337
What is the generation time of mycobacterium leprae?
10 to 30 days
338
How long is the generation time of environmental bacteria?
measured in months
339
How long is a pathogens generation time?
relatively short
340
What is the equation that can be used to calculate the size of a population?
Nt=(N)2h
N is total number of cells in pop.
t denotes at some point in time
N represents starting number of cells
exponent denotes generation number
2n represents number of cells in generation
341
growth curve
a predictable pattern of a bacterial population growth in a closed system can be measured
342
lag phase
a "flat" period of growth due to newly innoculated cells require adjustment period
cells are not yet multiplying at max rate
population is sparse
343
exponential growth phase
growth curve increases geometrically
will continue as long as cells have adequate nutrients and the environment is favorable
344
stationary growth phase
cell birth & cell death rates are equal
cell division rate is slowing down
caused by depleted nutrients and oxygen, plus excretion of organic acids and biochemical pollutants
345
death phase
cells begin to die at an exponential rate due to build up of wastes
speed of death depends on conditions
slower than exponential growth rate
346
viable nonculturable state
many cells in a culture in the death phase stay alive but are dormant
will not grow on culture medium and are missed in colony counts
347
What phase is more susceptible to antimicrobial agents and heat?
exponential growth phase
348
What stage is more likely to spread infection?
individual in the early stages of infection
349
turbidity
a clear nutrient solution becomes turbid, or cloudy, as microbes grow in it
greater turbidity=larger population size
