Exam 1 Flashcards
(273 cards)
1
Q
Cellular organisms include
A
- fungi
- protists
- bacteria
- archaea
2
Q
Acellular organisms include
A
- viruses
- viroids
- satellites
- prions
3
Q
Viruses are composed of
A
protein and nucleic acid
4
Q
Viroids are composed of
A
RNA
5
Q
Satellites are composed of
A
nucleic acid, often RNA
6
Q
Prions are composed of
A
protein
7
Q
Prokaryotic cells lack what?
A
a true membrane
8
Q
T / F: prokaryotic cells always lack a true membrane
A
F
9
Q
What is true of eukaryotic cells?
A
eukaryotic cells have a membrane enclosed nucleus, are morphologically complex, and are usually larger than prokaryotic cells
10
Q
The three domain system is based on a comparison of what?
A
ribosomal RNA genes
11
Q
The 3 domains
A
- bacteria
- archaea
- eukaryotes
12
Q
Cyanobacteria produce significant amounts of
A
oxygen
13
Q
Archaea are distinguished from bacteria by what?
A
unique rRNA gene sequences
14
Q
Some Archaea have unique __________ and _________
A
metabolic characteristics, membrane lipids
15
Q
Many Archaea live where?
A
in extreme conditions
16
Q
Protists are generally _____ than Bacteria and Archaea
A
larger
17
Q
Algae + cyanobacteria produce ____% of oxygen
A
75
18
Q
Yeast are a ___cellular fungi
A
uni
19
Q
Mold are _____cellular fungi
A
multi
20
Q
What yeast is often used in labs?
A
Sacchromyces cervesiae
21
Q
_____ are the smallest of all microbes
A
viruses
22
Q
Viruses require ________ to replicate
A
host cell
23
Q
T / F: some viruses can cause cancer
A
T
24
Q
T / F: oldest fossils on earth are microbial fossils
A
T
25
How old is the oldest fossil?
3.5 billions years old
26
_______ were the first life forms on earth
bacteria
27
For how long were bacteria the only life form on earth?
4.6 bya
28
What was the earliest molecule?
RNA
29
Ribozymes
RNA molecules that perform cellular work
30
Ribozymes are functional as what?
RNA
31
Earliest cells may have been RNA surrounded by _____
liposomes
32
______ is the precursor to double stranded DNA
RNA
33
The endosymbiotic hypothesis
the theory that some of the organelles in eukaryotic cells were once highly efficient prokaryotic cells
34
Which organelles are thought to originate from endosymbiont?
mitochondria and chloroplasts
35
Why are mitochondria and chloroplasts thought to uphold the endosymbiont theory?
mitochondria and chloroplasts contain DNA/RNA
36
rRNA genes show bacterial ______
lineage
37
16S rRNA (length, role)
- 1,500 nt RNA molecule
- structural role in the ribosome
- acts as a scaffold defining the positions of the ribosomal protein
38
Two regions of 16S rRNA
- highly conserved regions
- hyper variable regions
39
16S rRNA is ideal for what?
phylogenetic analysis due to the slow rate of evolution of the gene
40
Few differences in 16S rRNA indicates
close relation between species
41
Evolutionary distance
aligned rRNA sequences from diverse organisms are compared and differences counted to derive a value
42
T / F: time of divergence is determined by evolutionary distance
F
43
Archaea and Eukarya evolved ________ of Bacteria
independently
44
Archaea and Eukarya diverged from ________ ancestry
common
45
_________ of genetic material led to selected traits
mutation
46
Bacteria and Archaea increase genetic pool by _______ within the same generation
horizontal gene transfer
47
Who was the first person to observe and describe microorganisms accurately?
Antony van Leeuwenhoek
48
The idea that micro-organisms are the result of the process of decay is what theory
spontaneous generation
49
Who disproved spontaneous generation theory?
Louis Pasteur
50
Miasma theory
disease caused by foul air and bad smells
51
Louis Pasteur demonstrated that microorganisms carry out what process?
fermentations
52
Louis Pasteur developed what process to avoid wine spoilage by microbes?
pasteurization
53
Who provided indirect evidence that microorganisms were the causal agents of disease?
Joseph Lister
54
Joseph Lister developed what system and what did it result in?
aseptic surgery techniques, fewer postoperative infections
55
Who established the relationship between Bacillus anthracis and anthrax?
Robert Koch
56
Koch's (4) Postulates
1. the microorganism must be present in every case of the disease but absent from healthy organisms
2. the suspected microorganisms must be isolated and grown in a pure culture
3. the same disease must result when the isolated microorganism is inoculated into a healthy host
4. the same microorganisms must be isolated again from the diseased host
57
What disease did Koch experiment on to test his postulates?
TB
58
Limitations of Koch's Postulates
- some organisms cannot be grown in pure culture
- using humans in completing the postulates is unethical
- asymptomatic carriage
- co-infections
- dysbiosis
59
Koch's work led to discovery of development of
- agar
- petri dishes
- nutrient broth and nutrient agar
- methods for isolating microorganisms
60
Taxonomy
science of biological classification
61
Taxonomy consists of what 3 separate but interrelated parts
- classification
- nomenclature
- identification
62
Highest taxonomic rank is ______
domain
63
Within domain
phylum, class, order, family, genus, species
64
Binomial system used 2 names, the first name is the ____ and the second is the ____
genus, species
65
Species
population of cells with similar characteristics
66
Genus name
italicized and capitalized
67
Species name
italicized but not capitalized
68
Gene nomencltaure
- three lowercase letters followed by an uppercase fourth letter
- italicized
- / abcD /
69
Protein nomenclature
- same four letters as gene name
- not italicized
- first and last letter capitalized
- AbcD
70
Prokaryotes differ from eukaryotes in _____ and _____
size, simplicity
71
Most prokaryotes lack
internal membrane systems (nuclear membrane, r and s ER, mitochondria)
72
Prokaryotes = what two domains?
bacteria and archaea
73
Overarching characteristics of prokaryotic cells
- no nucleus
- one chromosome
- usually unicellular
- no organelles
- 70S rRNA
- plasma membrane
- cell wall
- 80-90% genome density CDS
- cell size: 1-10 micro m
74
Most common bacterial shapes
cocci and rod
75
Arrangement of bacterial cells is determined by
plane of division
76
Diplococci
pairs
77
Streptococci
chains
78
Staphylococci
grape-like clusters (dividing in alternating planes)
79
Tetrads
4 cocci in a square
80
Sarcina
cubic configuration of 8 cocci
81
Coccobacilli
very short rods
82
Streptobacilli
chain of rods
83
Vibrios
resemble curved rods, comma shaped
84
Spirilla
rigid helices
85
Spirochetes
flexible helices
86
Mycelium
network of long, multinucleate filaments
87
Pleomorphic
organisms that are variable in shape
88
Smallest bacteria (name and size)
0.3 micro m, Mycoplasma
89
Average rod size
1.1-1.5 micro m wide x 2-6 micro m long
90
______ is one of the biggest viruses that infects humans
Pox virus
91
Bacterial genome size (range)
500,000 bp to 10 million bp
92
What increases S/V ratio?
corkscrew shape
93
_____ cell size increases S/V ratio
small
94
Bacterial cell organization (3) common features
1. cell envelope
2. cytoplasm
3. external structures
95
Layers of cell envelope
1. cell membrane
2. wall
3. S-layer
96
All bacteria must have
cell membrane, cell wall, cytoplasm
97
_____ and ______ are variable to bacteria
S-layer, external structures
98
Typical bacterial cell structure (describe)
plasma membrane is further in than cell wall which is further in than capsule
99
Layers outside cell wall
S-layer, capsule
100
__________ is an absolute requirement for all living organisms
plasma membrane
101
Plasma membrane functions
- encompasses the cytoplasm
- selectively permeable barrier
- interaction with external environment
- metabolic processes
102
Hydrophobic regions associate with each other (_____), hydrophilic regions exposed (______)
inside, outside
103
Peripheral = ________% total membrane protein
20-30
104
Peripheral protein characteristics
- loosely attached to membrane
105
Integral protein = ____% of total membrane protein
70-80
106
Integral protein characteristics
- amphipathic (embedded within membrane)
- carry out important functions
- may exist in microdomains
107
Saturated bacterial lipids = ___ fluid
less
108
Hopanoids
sterol-like molecules, stabilize membrane
109
Macronutrients
- C, O, H, N, S, P
- found in organic molecules such as proteins,
lipids, carbohydrates, and nucleic acids
- K, Ca, Mg and Fe
- cations and serve in variety of roles including
enzymes, biosynthesis
- required in relatively large amounts
- mostly needed as cofactors for enzymes
110
Micronutrients
- trace elements
- Mn, Zn, Co, Mo, Ni and Cu
- often supplied in water or in media components
- ubiquitous in nature
- serve as enzymes and cofactors
- passively enter the cell
111
Growth factors
- organic compounds
- essential cell components (or their precursors) that the cell cannot synthesize
- must be supplied by environment if cell is to survive
- any organic compound that a cell must take up
112
Amino acids are needed for _____ synthesis
protein
113
Purines and pyrimidines are needed for ______ synthesis and are the basic building blocks for ____
nucleic acid, DNA
114
Vitamins function as _______
enzyme cofactors
115
Heme
iron
116
An example of nutritional immunity
body keeps iron in a form that is inaccessible to bacteria
117
What two transport mechanisms do all microorganisms use?
facilitated diffusion, active transport
118
Group translocation is used by
bacteria and archaea
119
Endocytosis is used by
Eukarya only
120
H2o, O2 and CO2 often move across membrane by
passive diffusion
121
Facilitated diffusion typically involves
carrier proteins
122
In facilitated diffusion, direction of movement is from ______ to _____ and, ____ require energy
high concentration to low concentration, does not
123
How does facilitated diffusion differ from passive diffusion?
- uses permeases (membrane bound carrier molecules)
- smaller concentration gradient is required for significant uptake of molecules
- effectively transports glycerol, sugars, and amino acids
124
Facilitated diffusion is more prominent in ____ than in
eukaryotic cells, bacteria or archaea
125
Passive diffusion is
linear
126
Active transport is a(n) ______-dependent process
energy
127
Active transport movement
- moves molecules against the concentration gradient
- concentrates molecules inside cell
128
3 types of active transport
1. primary active transport
2. secondary active transport
3. group translocation
129
Primary active transport (characteristics, what microorganisms it is observed in)
- ABC transporters
- use ATP
- observed in bacteria, archaea and eukaryotes
- consists of 2 hydrophobic membrane spanning domains, 2 cytoplasmic associated ATP-binding domains, substrate binding domains
130
Secondary active transport
- use ion gradients to cotransport substances (instead of ATP!)
- symport
- antiport
131
Symport
two substances both move in the same direction
132
Antiport
two substances move in opposite directions
133
Group translocation
- energy dependent transport that chemically modifies molecule as it is brought into cell
- a variety of sugars can be transported by PTS systems
- Enzyme I and Hpr are the same in all PTS systems
- specificity lies with Enzyme II
134
Siderophore
secreted by microorganisms to aid in iron uptake
135
Cell wall functions
- maintains shape of the bacterium
- helps protect cell from osmotic lysis
- helps protect from toxic materials
- may contribute to pathogenicity
136
T / F: a lot of bacteria can survive without cell wall (no osmotic pressure) but not without cell membrane
T
137
Gram-positive bacteria stain
purple
138
Gram-negative bacteria stain
pink
139
T / F: peptidoglycan is found in bacterial cell wall and nowhere else
T
140
Area between peptidoglycan and plasma membrane
periplasm
141
Peptidoglycan (murein)
rigid polymer structure that lies just outside the cell plasma membrane
142
Gram (+) peptidoglycan: _____ nm thick
20-80
143
Gram (-) peptidoglycan: ______ nm thick
2-7
144
Peptidoglycan structure
- two alternating sugars: NAM and NAG
- peptide strand (alternating D- and L- amino acids)
145
L amino acid is connected to NAM or NAG?
NAM
146
Chains in peptidoglycan are crosslinked to other chains via
peptides
147
Crosslinking can be direct or
by a peptide inter-bridge
148
Most common #3 amino acid is
DAP
149
Most common type of linkage is
3 - 4 linkage
150
Amino acid at #3 position can be
- DAP
- L-Lys
- L-Hsr
151
Linkage types
3 - 4
2 - 4
152
Composition of linkage
- direct
- bridged
153
Protein translation by ribosomes exclusively utilizes
L-amino acids
154
T / F: D-amino acids are common
F
155
The most common place in nature to find D-amino acids
bacterial cell wall
156
Peptidoglycan backbone
- alternating NAM-NAG sugars
- beta-(1,4) linked
- beta-(1,4) glyosidic bond
157
Gram (+) cell walls
- 20-80 nm thick peptidoglycan
- may also contain teichoic acids
158
Teichoic acids
- polymer consisting of alternating phosphate/sugar groups
- (-) charged
- help maintain cell envelope
- protect from environmental substances
- may bind to host cells
- covalently connected to peptidoglycan
- may also be covalently connected to lipids in plasma membrane (LTA)
159
TA: anchored to ____
cell wall
160
LTA: anchored to/in _____
plasma membrane
161
Sortase
- periplasmic protein
- anchors other proteins to cell wall
162
Periplasmic space of Gram (+) bacteria is ____ than that of Gram (-)
smaller
163
Gram (+) cell walls
- important for virulence
- covalently linked to peptidoglycan
- proteins have protein sequence LPXTG
- covalently linked to peptidoglycan through T residue by enzyme sortase
164
Gram (-) cell walls are _____ complex than Gram (+) cell walls
more
165
Gram (-) cell walls
- consist of a thin layer of peptidoglycan surrounded by an outer membrane (OM)
- outer membrane composed of lipids, lipoproteins and LPS
- no teichoic acids
- plasma membrane sometimes called inner membrane (IM)
166
Important differences between Gram (-) and (+) cell walls
- Gram (+) cell walls have no OM
- Gram (+) cell walls have thicker peptidoglycan/cell wall
- Gram (-) has LPS, no TA
167
Periplasmic space of Gram (-) cell
- 20-40% of cell volume
- many enzymes present (hydrolytic enzymes, transport proteins, etc.)
168
In Gram (-) cell walls, the OM lies
outside thin peptidoglycan layer
169
OM is _____ bonded to peptidoglycan by
covalently, Braun's lipoprotein
170
Outer surface of OM consists of
LPS
171
Inner layer of OM composed of
phospholipids
172
T / F: LPS is only found in Gram (-) bacteria
T
173
LPS structure
1. O side chain (O antigen) (extended out from cell)
2. core polysaccharide
3. lipid A (embedded in OM)
174
Importance of LPS
- core polysaccharide contributes to (-) charge on cell surface
- lipid A helps stabilize OM structure
- creates a permeability barrier
- O antigen protects from host defenses
- lipid A can act as a toxin (endotoxin)
175
Gram (-) OM permeability
- more permeable than IM due to presence of porin proteins
- porin proteins form channels to let small molecules pass
176
One major function of the cell wall is to protect the bacterial cell from
osmotic stress
177
Hypotonic environments
- solute concentration is higher inside the cell
- water moves into cell and cell swells
- cell wall protects from lysis
178
Hypertonic environments
- solute concentration is higher outside the cell
- water leaves the cell
- plasmolysis occurs (shrinking of cytoplasm)
179
If peptidoglycan cell wall is removed...
- cells will lyse if they are in a hypotonic solution
- survive in isotonic solution
180
Gram (+) bacteria without peptidoglycan
protoplasts
181
Gram (-) bacteria without peptidoglycan
spheroplasts
182
3 most common types of components outside the cell wall
- capsules
- slime layers
- S-layers
183
Capsules
- usually composed of polysaccharides
- resistant to phagocytosis
- protect from desiccation
- exclude viruses and detergents
- well organized, not easily removed from cell
184
Slime layers
- may aid in motility
- similar to capsules except diffuse, unorganized and easily removed
185
S-layers
- regularly structured layers of protein or glycoprotein that self-assemble
- Gram (-): S-layer adheres to OM
- Gram (+): S-layer is associated with the peptidoglycan surface
186
Cytoplasm
material bounded by the plasmid membrane
187
Bacterial cytoplasmic structures (5)
- cytoskeleton
- intracytoplasmic membranes
- ribosomes
- nucleoid and plasmids
- inclusions
188
Cytoskeleton (3 eukaryotic cytoskeletal elements, role, homologs)
- 3 eukaryotic cytoskeletal elements: actin, tubulin, intermediate filaments
- plays role in cell shape and structure, internal organization, localization of components within the cell
- homologs of all three have been identified in bacteria
189
FtsZ
- tubulin homolog
- found in many bacteria
- forms ring during septum formation in cell division
190
MreB
- actin homolog
- maintains shape by positioning peptidoglycan synthesis machinery
- found in rods
191
CreS
- IF homolog
- rare
- maintains shape in curved bacteria (prevents peptidoglycan synthesis on one side)
192
Intracytoplasmic membranes
- extension of the plasma membrane into cytoplasm
- many metabolic reactions can only happen in/at a membrane, provides more surface area that can then provide space for reactions
- observed in many photosynthetic bacteria and bacteria with high respiratory activity
193
Ribosomes
- complex protein/RNA structures
- sites of protein synthesis
194
Bacterial and archaeal ribosome
70S
195
Eukaryotic ribosome
80S
196
Bacterial rRNA
- 16S small subunit
- 23S and 5S in large subunit
197
Ribosomes are found where in bacteria?
free floating in cytoplasm
198
The nucleoid
- genetic material of the cell
- usually not membrane bound
- consists of chromosome and associated proteins
- usually 1 closed circular, DS DNA molecules
199
______ condenses nucleoid
Supercoiling
200
Plasmids
- extrachromosomal DNA
- exist and replicate independently of chromosome
- contain non-essential genes
201
Episomes
when plasmids integrate onto chromosomes
202
Inclusions
- granules or organic or inorganic material that are stockpiled by the cell for future use
- general term for anything random found in cytoplasm
203
External structures (functions)
- attachment to surfaces
- cell movement
- protection
- horizontal gene transfer
204
3 best known examples of external structures
- pili
- fimbriae
- flagella
205
Pili and fimbriae
- short, thin, hair-like appendages (up to 1,000 per cell)
- proteinaceous
- helical tubes
- functions include attachment to surfaces, motility and DNA uptake
- attachment to surfaces is main function
206
Sex pilus
- longer, thicker, less numerous
- genes for formation found on plasmids
- required for conjugation
- forms between bacterial cells
207
Flagella
- long thread-like appendages extending outward from plasma membrane and cell wall
- up to 20 micro m in length
- functions include motility, attachment to surfaces, virulence factors
- motility is main function, acts as a propeller
- can be 4-5x larger than the cell
- corkscrew shape
208
Monotrichous
one flagellum
209
Polar (flagella distribution)
flagellum at end of cell
210
Amphitrichous
one flagellum at each end of cell
211
Lophotrichous
cluster of flagella at one or both ends
212
Peritrichous
spread over entire surface of cell
213
3 parts of flagella
1. filament
- extends from cell surface to the tip
- hollow, rigid cylinder of flagellin protein
2. hook
- links filament to basal body
3. basal body
- series of rings that drive flagellar motor
214
Filament subunits self-assemble with help of filament cap at
tip, not base
215
Chemotaxis
move toward chemical attractants such as nutrients, away from harmful substances
216
4 common types of motility
- flagellar movement
- spirochete motility
- twitching motility
- gliding motility
217
Flagellar movement
- flagellum rotates like a propeller (very rapid rotation)
- CCW: forward motion (run)
- CW: cell spins around (tumble)
218
Spirochete motility
- flagella remain in periplasmic space inside OM (periplasmic flagella)
- multiple flagella form axial fibril which winds around the cell
- corkscrew shape exhibits flexing and spinning movements
219
Twitching motility
- pili at ends of cell
- extend and contact surface
- retract, pulling the cell forward
- short, intermittent, jerky motions
220
Gliding motility
- not well-defined process
- various proposed mechanisms
- smooth movements
- smile layers?
221
In a graph of flagellar mediated chemotaxis:
- each corner indicates a _______
- in absence of attractant, flagella rotate CCW and CW with ______ frequency
- when concentration of attractant increases, the frequency of CW is _____, runs in direction of attractant are ______
- when concentration of attractant decreases, frequency of CW is ______, cell redirects until _______
- tumble
- equal
- reduced, longer
- increased, moving towards attractant
222
The bacterial endospore
- complex, dormant structure formed by some bacteria
- various locations within the cell
- resistant to numerous environmental conditions (heat, radiation, chemicals, desiccation)
223
Sporulation
- process of endospore formation
- occurs in hours (up to 10)
- normally commences when growth ceases because of lack of nutrients
- complex, multistage process
224
Purpose of sporulation
survival and preservation of the genetic matieral
225
Formation of vegetative cell
- activation (prepares spores for germination, often results from treatments like heating)
- germination (environmental nutrients are detected, spore swelling and rupture of spore coat, increased metabolic activity)
- outgrowth (emergence of actively growing cell)
226
One thing Archaea are not known to do
cause disease in humans
227
Archaeal size, shape, arrangement
- cocci and rods are common shapes (others can exist)
- no spirochetes or mycelial forms yet
- branched/flat shapes
- sizes vary (typically 1-2 x 1-5 micro m for rods, 1-5 micro m diameter for cocci)
- smallest observed is 0.2 micro m in diameter
228
Properties that bacteria and archaea have in common
- inclusions
- ribosomal size
- chromosomal structure
- plasmids
- external strucutres
229
Archaeal cell envelopes
cell envelope consists of
- plasma membrane
- no peptidoglycan
- cell wall (some lack one, however)
- additional external layers (S-layer may be only component outside plasma membrane, capsules and slime layers are rare)
230
Archaeal envelopes differ from bacterial envelopes in
the molecular makeup and organization
231
Archaeal membrane lipids (building block, composition)
- composition is very different than that of bacteria
- building block is 5 carbon branched molecule isoprene
- lipid chains of isoprene are branched, unlike the chains of bacterial phospholipids
232
Branching of membrane lipids affects
fluidity of membrane
233
Archaeal lipids are attached to glyercol by
ether linkages
234
Bacterial lipids are attached to glycerol by
ester linkages
235
Some archaeal lipids and membranes have...
- diglycerol tetraethers
- pentacyclic rings (increases membrane rigidity)
236
Archaeal lipid and membrane composition supports what idea?
that archaea evolved independently of bacteria
237
Most common type of archaeal cell envelope is
S-layer outside plasma membrane
238
Additional layer outside of the S layer may be composed of
polysaccharide
239
Some archaeal cell walls contain a peptidoglycan-like polymer called
pseudomurein
240
Differences between pseudomurein and peptidoglycan
- beta,1-3 linkage
- no D amino acids
- NAT and NAG
241
Protein translation by ribosomes exclusively utilizes
L-amino acids
242
Archaeal cell walls have a thick _______ layer, and often stain
polysaccharide, Gram (+)
243
Archaeal cells use what mechanisms for nutrient uptake
- primary active transport
- secondary active transport
244
T / F : archaea have more proteins than bacteria
T
245
5.8S suggests relationship between
eukaryotes and archaea
246
_____ may be involved in archaeal adhesion mechanisms
pili
247
Cannulae
- hollow, tube-like structures on the surface of thermophilic archaea in the genus Pyrodictium
- function is unknown
- connects cells together, helps them adhere to each other and the surface around them
248
Hami
- not well understood
- looks like a grappling hook
- involvement in cell adhesion mechanisms (?)
249
Archaeal flagella: growth occurs where?
at the base
250
Differences of archaeal flagella
- thinner than bacterial flagella
- more than one type of flagellin protein
- flagellum are not hollow
- hook and basal body are difficult to distinguish
- add subunits to base, not tip
251
Two groups of eukaryotes commonly possess microbial members
- protists
- fungi
252
T / F: protist is a taxonomic group
F
253
Eukaryotic cell envelopes
- plasma membrane is lipid bilayer
- consists of plasma membrane and all coverings attached to it
- usually don't have cell wall (protists and fungi do)
- sphingolipids and cholesterol contribute to strength of membrane
254
Cell walls of photosynthetic algae commonly composed of
cellulose, pectin, and silica
255
Cell walls of fungi consist of
cellulose, chitin or glucan
256
T / F: cell wall of a eukaryotic cell is typically complex
F
257
Cytoplasm of eukaryotes
- consists of the cytosol and many organelles
- cytoskeleton plays a role in cell shape and movement (microfilaments, microtubules, intermediate filaments)
258
_____ cytoskeletal component is involved in cell motion and shape changes
actin filaments
259
Intermediate filaments
- heterogeneous elements of the cytoskeleton
- role in cell is unclear
- play a structural role
- some shown to form nuclear lamina, others help link cells together to form tissues
260
Microtubules
- think cylinders
- help maintain cell shape
- involved with actin filaments in cell movements
- participate in intracellular transport processes
261
Lysosomes
- intracellular digestion (important for clearing microbes from eukaryotic cells)
- contain hydrolases (enzymes that hydrolyze molecules and function best under slightly acidic conditions)
- maintain an acidic environment by pumping protons into their interior
262
Endosytosis
- used to bring materials into the cell
- solutes or particles taken up and enclosed in vesicles pinched from plasma membrane
263
Phagocytosis
- cell surface protrusions surround and engulf particles
- particles are taken up inside a membrane bound vesicle
264
Receptor mediated endocytosis
- external receptors on cell surface
- specifically bind macromolecules
- binding triggers endocytosis
- receptor and bound molecule are taken up
265
Eukaryotic ribosomes
- may be attached to ER or free in cytoplasmic matrix
- when present in ER: bound via 60S subunit
266
ER ribosomes
secreted and membrane proteins
267
Free ribosomes
cytoplasmic proteins
268
External cell covering (eukaryotic cells) and what they are associated with
- cilia, movement
- flagella, movement
269
______ may have lateral hair-like projections
flagella
270
_______ move in an undulating fashion
- wave from base to tip, pushes cell
- wave from tip to base, pulls cell
flagella
271
_______ beat with two phases, working like oars, and have highly coordinated movements
cilia
272
In what type of cell are introns rare in?
archaeal and bacterial
273
Describe the plasma membrane lipids of
- bacterial cells
- archaeal cells
- eukaryotic cells
- bacterial cells: ester-linked phospholipids and hopanoids; some have sterols
- archaeal cells: glycerol di-ethers and diglycerol tetraethers
- eukaryotic cells: ester-linked phospholipids and sterols
