Gen Charac Of Bacteria Flashcards
(160 cards)
1
Q
True or false:
Prokaryotic and eukaryotic cells both contain nucleic acids, proteins, lipids, and carbohydrates.
A
True
2
Q
True or false:
Prokaryotic and Eukaryotic cells use the same kinds of chemical reactions to metabolize food, build proteins, and store ener
A
True
3
Q
True or false:
Prokaryotic and eukaryotic cells have the same structure of cell walls and membranes, and the absence of organelles.
A
False. They differ in structure of cell walls and membranes, and the absence of organelles .
4
Q
CHIEF DISTINGUISHING CHARACTERISTICS OF
EUKARYOTES:
- DNA is found in the _____________, which is separated from the cytoplasm by a nuclear membrane, and the DNA is found in multiple chromosomes
- DNA is consistently associated with chromosomal proteins called ___________ and with nonhistone
- Have a number of ____________________
- Cell walls, when present, are chemically __________
- Cell division usually involves __________
A
- DNA is found in the cell ‘s nucleus, which is separated from the cytoplasm by a nuclear membrane, and the DNA is found in multiple chromosomes
- DNA is consistently associated with chromosomal proteins called histones and with nonhistone
- Have a number of membrane-enclosed organelles
- Cell walls, when present, are chemically simple
- Cell division usually involves Mitosis
5
Q
CHIEF DISTINGUISHING CHARACTERISTICS OF
PROKARYOTES
- DNA is not enclosed within a membrane and is usually a __________________ chromosome (prokaryotes have no true nucleus)
- DNA is not associated with _____________; other proteins are associated with the DNA.
- Lack _________________
(ex: mitochondria, golgi apparatus) - Cell walls almost always contain the ____________________
- Usually divide by ____________
→DNA is copied, and the cell splits into two cells
→involves fewer structures and processes than eukaryotic cell division
A
- DNA is not enclosed within a membrane and is usually a singular circularly arranged chromosome (prokaryotes have no true nucleus)
- DNA is not associated with histones; other proteins are associated with the DNA.
- Lack membrane-enclosed organelles
(ex: mitochondria, golgi apparatus) - Cell walls almost always contain the complex polysaccharide peptidoglycan
- Usually divide by Binary Fission
→DNA is copied, and the cell splits into two cells
→involves fewer structures and processes than eukaryotic cell division
6
Q
- unicellular organisms that lack a nuclear membrane and true nucleus
- classified as prokaryotes (Greek: before kernel [nucleus]), having no mitochondria, endoplasmic reticulum (ER), or Golgi bodies (they only have ribosomes)
A
Bacteria
7
Q
Vary in size, morphology, and cell to-cell arrangements and in the chemical composition and structure of the cell wall
A
BACTERIAL MORPHOLOGY
8
Q
Bacterial cell wall differences provide the basis for the __________
A
Gram stain
9
Q
Most clinically relevant bacterial species range in size from ___________ in width and ___________ in length
A
Most clinically relevant bacterial species range in size from 0 .25 to 1 μm in width and 1 to 3 μm in length
10
Q
True or false:
Bacterium is some hundred-fold larger than a virus, and ten-fold smaller than a eukaryotic cell
A
True
11
Q
True or false:
Variation of size and shape within a population may also result from asymmetric growth of the cell wall
A
True
12
Q
Bacterial shape
A
Cocci
Coccobacilli
Bacillus
Fusiform
Curved
Spiral
Pleomorphic
13
Q
Cluster: ______________
Chains: ______________
Pairs: __________
Tetrads:__________
A
Cluster: Staphylococci
Chains: Streptococci
Pairs: Diplococci
Tetrads:Micrococcus
14
Q
BACTERIAL ARRANGEMENT
A
a) Pairs
b) Chains
c) Grape-like clusters
d) Group of four
e) Packets of eight
f) Palisades
g) Chinese characters
15
Q
outermost structure
comprises of outer membrane, cell well, periplasm, cytoplasmic or cell membrane
A
Cell envelop
16
Q
- Found only in gram-negative bacteria
- Function as cell’s initial barrier to the environment
A
Outer membrane
17
Q
a void space between your outer membrane and inner membrane
A
periplasmic space
18
Q
- Bilayered structure composed of lipopolysaccharide Which gives the surface of gram-negative bacteria a net negative charge
- Plays a significant role in the ability of certain bacteria to cause disease
A
Outer membrane
19
Q
- Protein structures scattered throughout the lipopolysaccharide macromolecules
- Water-filled structures that control the passage of nutrients and other solutes, including antibiotics,
through the outer membrane - Number and types of porins vary with bacterial species
- Influence the extent to which various substances pass through the outer membranes of different bacteria
A
Porins
20
Q
Facilitate the attachment of the outer membrane to
the next internal layer in the cell envelope, the cell
wall
A
MUREIN LIPOPROTEINS
21
Q
- Referred to as the PEPTIDOGLYCAN, or MUREIN
LAYER - Gives the bacterial cell shape and strength to
withstand changes in environmental osmotic
pressures that would otherwise result in cell lysis
A
CELL WALL ( MUREIN LAYER)
22
Q
- Protects against mechanical disruption of the cell and offers some barrier to the passage of larger
substances - Synthesis and structure are often the primary targets for the development and design of several
antimicrobial agents
A
Cell wall (murein layer)
23
Q
Cell wall structure is composed of __________________
A
DISACCHARIDE-PENTAPEPTIDE SUBUNITS
24
Q
- Alternating sugar components (moieties),with the
amino acid chain linked to N-acetylmuramic acid molecules - Polymers of these subunits cross-link to one another by means of peptide bridges to form peptidoglycan
sheets - Layers of these sheets are cross-linked with one
another, forming a multilayered, cross-linked structure of considerable strength
A
N-ACETYL-D-GLUCOSAMINE AND N-ACETYL-D-MURAMIC ACID
25
Referred to as the_____________, or sack, this
peptidoglycan structure surrounds the entire cell
MUREIN SACCULUS
26
Major types of cell walls:
gram-positive and gram-negative types
27
stain gram-positive, have a modified cell wall called ACID-FAST CELL WALL
Mycobacteria
28
microorganisms that have no cell wall
Mycoplasmas
29
Primary stain use in acid-fast stain
carbol fuchsin
30
- Composed of a very thick protective peptidoglycan (murein)layer
- Consists of glycan (polysaccharide) chains of
alternating N-acetyl-d- glucosamine (NAG) and N-
acetyl-d-muramic acid (NAM)
- many antibiotics effective against gram-positive
organisms (e.g., penicillin) act by preventing synthesis
of peptidoglycan
GRAM-POSITIVE CELL WALL
31
thinner layer of peptidoglycan
and a different cell wall structure, are less affected by these antibiotics
Gram-negative bacteria
32
OTHER COMPONENTS OF GRAM-POSITIVE CELL WALL THAT PENETRATE TO THE EXTERIOR OF THE CELL
TEICHOIC ACID
LIPOTEICHOIC ACID
TEICHURONIC ACID
33
- anchored to the peptidoglycan (N-acetylmuramic acid)
- glycerol or ribitol phosphate polymers combined with
various sugars, amino acids, and amino sugars
TEICHOIC ACID
34
- anchored to the PM (plasma membrane)
- linked to the next underlying layer, PM or cellular
memebrane
LIPOTEICHOIC ACID
35
two components that are unique to the gram-positive cell wall
TEICHOIC ACID
LIPOTEICHOIC ACID
36
- similar polymers, but the repeat units include sugar
acids (eg, N-acetylmannosuronic or d-glucosuronic
acid) instead of phosphoric acids
- synthesized in place of teichoic acids when phosphate is limiting
TEICHURONIC ACID
37
Two layers of gram-negative cell wall
Inner peptidoglycan layer
Outer membrane
38
- much thinner than in gram-positive cell walls
Inner peptidoglycan layer
39
- Outside the peptidoglycan layer is an additional outer membrane
- contains proteins, phospholipids, and lipopolysaccharide (LPS)
Outer membrane
40
LPS THREE REGIONS
O-specific polysaccharide
Core polysaccharide
Lipid A (also called endotoxin)
41
LPS region that is antigenic
O-specific polysaccharide
42
LPS region with ketodeoxyoctanoic acid (KDO) and heptose
Core polysaccharide
43
LPS region:
- inner, major constituents
Lipid A (also called endotoxin)
44
LPS functions:
- Vital in evading the host defenses
- Contribute to the negative charge of the bacterial surface, which stabilizes the membrane structure
- Considered as an endotoxin
45
- consists of phosphorylated glucosamine disaccharide units to which are attached a number of long-chain fatty acids
- responsible for producing fever and shock conditions in patients infected with gram-negative bacteria
Lipid A moiety
46
Outer membrane function:
- Acts as a barrier to hydrophobic compounds and
harmful substances
- Acts as a sieve, allowing water-soluble molecules to
enter through protein-lined channels called porins
- Provides attachment sites that enhance attachment to host cells
- Strong negative charge is an important factor in
evading phagocytosis
- Acts as a barriers to toxic substances that prevents movement inside the cell
47
Peptidoglycan layer of Gram(+) bacteria
Thick(multilayered)
48
Teichoic Acids of Gram(+) bacteria
Present in many
49
Periplasmic Space of Gram(+) bacteria
Absent
50
Outer Membrane of gram (+) bacteria
Absent
51
LPS content of gram(+) bacteria
Virtually none
52
Lipid and LPP of gram(+) bacteria
Low
53
Flagellar structure of gram(+) bacteria
2 Rings in basal body
54
Toxins produced by gram(+) bacteria
Exotoxins
55
Resistance to Physical Disruption of gram(+) bacteria
High
56
Cell Wall Disruption by Lysozyme of gram(+) bacteria
High
57
Susceptibility to Pen and Sulfonamide of gram(+) bacteria
High
58
Susceptibility to Strep, Chloram and Tetra of gram(+) bacteria
Low
59
Inhibitions by Basic Dyes of gram(+) bacteria
High
60
Resistance to Anionic Detergents of gram(+) bacteria
Low
61
Resistance to Sodium Azide of gram(+) bacteria
High
62
Resistance to Drying of gram(+) bacteria
High
63
Peptidoglycan layer of gram(-) bacteria
Thin (bilayered/trilayered)
64
Teichoic Acids of gram (-) bacteria
Absent
65
Periplasmic Space of gram(-) bacteria
Present
66
Outer Membrane of gram(-) bacteria
Present
67
LPS content of gram(-) bacteria
High
68
Lipid and LPP of gram(+) bactera
High
69
Lipid and LPP of gram(+) bactera
High
70
Flagellar structure of gram (-) bacteria
4 rings in basal body
71
Toxins produced by gram(-) bacteria
Endotoxins and exotoxins
72
Resistance to Physical Disruption of gram(-) bacteria
Low
73
Cell Wall Disruption by Lysozyme of gram(-) bacteria
Low
74
Susceptibility to Pen and Sulfonamide of gram(-) bacteria
Low
75
Susceptibility to Strep, Chloram and Tetra of gram(-) bacteria
High
76
Inhibitions by Basic Dyes of gram(-) bacteria
Low
77
Resistance to Anionic Detergents of gram(-) bacteria
High
78
Resistance to Sodium Azide of gram(-) bacteria
Low
79
Resistance to Drying of gram(-) bacteria
Low
80
- Spherical,rod-shape or filamentous
- Chemoorganoheterotrophic
- endospore present in some groups
- reproduction by binary fission
Gram-positive bactera
81
- Spaherical, oval,straightor curved,helical or filamentous
- Phototrophic, chemolitoautotrophic, Chemoorganoheterotrophic
- endospore: absent
- reproduction by binary fission
Gram-negative bacteria
82
- Typically found only in gram-negative bacteria
- Bounded by the internal surface of the outer membrane and the external surface of the cellular membrane encompassing the thin peptidoglycan layer
Periplasmic space
83
True or false:
Periplasmic space is absent in gram-positive bacteria
True
84
- Have a gram-positive cell wall structure
- Contain a waxy layer of glycolipids and fatty acids
(myolic acid) bound to the exterior of the cell wall
- More than 60% of the cell wall is lipid
ACID-FAST CELL WALL
85
- Major lipid component
- Strong “hydrophobic” molecule that forms a lipid shell around the organism and affects its permeability
- Makes Mycobacterium spp. difficult to stain with the Gram stain
Mycolic Acid
86
- Lack a cell wall and contain sterols in their cell
membranes
- Lack the rigidity of the cell wall
- Seen in various shapes microscopically
ABSENCE OF CELL WALL
87
- Present in both gram-negative and gram-positive
bacteria and is the deepest layer of the cell envelope
- Consist of phospholipid bilayer, various proteins
(70%), including a number of enzymes vital to cellular metabolism
- Serves as an additional osmotic barrier
- Absence of sterols
CYTOPLASMIC (INNER) MEMBRANE
88
- Transport of solutes into and out of the cell
- Housing of enzymes involved in outer membrane
synthesis, cell wall synthesis, and the assembly and
secretion of extracytoplasmic and extracellular
substances
- Generation of chemical energy (i.e., ATP)
- Cell motility
- Mediation of chromosomal segregation during replication
Functions of cytoplasmic (inner) membrane
89
Relies on diffusion, uses no energy, and operates
only when the solute is at higher concentration
outside than inside the cell
PASSIVE TRANSPORT
90
Accounts for the entry of very few nutrients, including dissolved oxygen, carbon dioxide, and water itself
SIMPLE DIFFUSION
91
Uses no energy so the solute never achieves an
internal concentration greater than what exists outside the cell (e.g., Glycerol)
FACILITATED DIFFUSION
92
Form selective channels that facilitate the passage of specific molecules
CHANNEL PROTEINS
93
- Move a molecule across the cell membrane at the
expense of a previously established ion gradient such as protonmotive or sodiummotive force
- Particularly common in aerobic organisms, which
have an easier time generating an ion-motive force
than do anaerobes
ION-COUPLED TRANSPORT
94
Three basic types of ION-COUPLED TRANSPORT
Uniport
Symport
Antiport
95
catalyze the transport of a substrate independent of any coupled ion
Uniport
96
simultaneous transport of two substrates in the same direction by a single carrier
Symport
97
simultaneous transport of two likecharged compounds in opposite directions by a common carrier (40% of the substrates transported by E. coli
Antiport
98
Uses ATP directly to transport solutes into the cell
ABC transport
99
Transport of many nutrients is facilitated by specific
binding proteins located in the periplasmic space
Gram-negative
100
Binding proteins are attached to the outer surface of the cell membrane
Gram-positive
101
- Vectorial metabolism
- Not active transport because no concentration
gradient is involved
- Allows bacteria to use their energy resources
efficiently by coupling transport with metabolism
GROUP TRANSLOCATION
102
Some pathogenic bacteria use specific receptors that bind host transferring and lactoferrin (as well as other iron-containing host proteins)
SPECIAL TRANSPORT PROCESSES
103
Compounds that chelate Fe and promote its transport as a soluble comples
SIDEPHORES
104
- Site of protein biosynthesis and give the cytoplasm a granular structure
- Consist of RNA and proteins
- 70S in size and separates into two subunits, 50S and 30S
Ribosomes
105
Attach to the 30S subunit and interfere with protein synthesis
Streptomycin and Gentamicin
106
Interfere with protein synthesis by attaching to the 50S subunit
Erythromycin and Chloramphenicol
107
- Consist of a single, circular chromosome
- Lacks nuclear membrane and mitotic apparatus
- Appears as diffused nucleoid or chromatin body that is attached to a mesosome (sac-like structure)
Genome
108
- Feulgen positive
- Consists of a single continuous circular molecule
ranging in size from 0.58 to almost 10 million base
pair
Exception: Borrelia burgdorferi and Streptomyces coelicolor
- Few bacteria have dissimilar chromosomes: Vibrio
cholera and Brucella melitensis
NUCLEOID
109
- Extrachromosomal, double-stranded element of DNA that is associated with virulence
- Located in the cytoplasm and serve as a site for the
genes to code for antibiotic resistance and toxin
production
- Not essential for bacterial growth so a bacterial cell
may or may not contain a plasmid
- Sometimes disappears during cell division and it can make bacteria (mostly Gram-neg) pathogenic
PLASMID
110
Two Kinds of Plasmid
Large Plasmid
Small Plasmid
111
responsible for the production of B- lactamase that provide resistance to B- lactam antibiotics (penicillin and oxacillin)
Large Plasmid
112
Resistant to tetracyclines and chloramohenicol
Small Plasmid
113
- Serve as the energy source or food reserve of the
bacteria or as a reservoir of structural building blocks
- Composed mainly of polysaccharides, they lessen
osmotic pressure
Inclusion bodies
114
Two common types of granules:
Glycogen
Polyphosphate granules
115
Storage form of glucose
Glycogen
116
- Storage form of inorganic phosphates
- Source of phosphate for nucleic acid and
phospholipid synthesis
Polyphosphate granules
117
- Lipid like compound consisting of chains of B-
hydroxybutyric acid units connected through ester
linkages
- Produced when the source of nitrogen, sulfur, or
phosphorous is limited and there is excess carbon on the medium
POLY-B-HYDROXYBUTYRIC ACID (PHB)
118
Carbon source when protein and nucleic acid
synthesis are resumed
PHB AND GLYCOGEN
119
Hydrogen sulfide and thiosulfate
Sulfur granules
120
- Small, dormant structures located inside the bacterial cell
- Aid in the survival of bacteria against external
conditions
- Produced within vegetative cells of some Gram-pos bacteria
- Composed of dipicolinic acid and calcium ions :Calcium Cipicolinate
- Some locations could be a means of microscopically identifying bacteria
- Responsible for perpetuation, but not multiplication
Examples : Bacillus and Clostridium
ENDOSPORES/ ASEXUAL SPORES
121
Types of Spores according to location:
Terminal spore
Subterminal spore
Central spore
122
Properties of Endospores
Core
Spore wall
Cortex
Ciat
Exosporium
123
Properties of Endospores
Core
Spore wall
Cortex
Ciat
Exosporium
124
- Spore protoplast
- Contains a complete nucleus (chromosome)
all of the components of the protein-synthesizing apparatus, and an energy-generating system based on glycolysis
Core
125
- Innermost layer surrounding the inner spore
membrane
- Contains normal peptidoglycan and becomes he cell wall of the germinating vegetative cell
Spore wall
126
- Thickest layer of the spore envelope
- Contains an unusual type of peptidoglycan,
with many fewer cross-links than are found in cell wall peptidoglycan
Cortex
127
- Composed of a keratin-like protein containing many intramolecular disulfide bonds
- Impermeability of this layer confers on spores their relative resistance to antibacterial chemical agents
Coat
128
-composed of proteins, lipids, and carbohydrates
- consists of a paracrystalline basal layer and a hairlike outer region
Exosporium
129
play a role in the mediation of infection and in
laboratory idedntification, varies among bacterial
species and even among strains within the same species
Cellular appendages
130
- outward complex of polysaccharide on the bacterial surface and other cells
- helps the bacteria to attach to the surface of the solid objects or tissues
- appears as a capsule or a slime layer
Glycocalyx
131
- organized and is firmly attached to the cell wall
- immediately exterior to the murein layer of gram-positive bacteria and the outer membrane of gram-negative bacteria
- made up of polysaccharide polymers
Capsule
132
- Unorganized material that is loosely attached to the cell wall
- Made up of polysaccharide
- Can either inhibit phagocytosis or aid in the
adherence of the bacteria to the host tissue or
synthetic implants
- Facilitates and maintains bacterial colonization of
biologic (e.g. teeth) and inanimate (e.g. prosthetic
heart valves) surfaces through the formation of
biofilms
Slime layer
133
- helps cells in a biofilm attach to their target environment and to each other
- protects the cells within it, facilitates communication among them and enables the cells to survive by attaching to various surfaces in their natural environment
Extracellular Polymeric Substance
134
- exterior protein filaments that rotate and cause
bacteria to be motile
- complex structures, mostly composed of the protein flagellin, intricately embedded in the cell envelope
- thread-like appendages composed entirely of protein, 12–30 nm in diameter
- plays an important role in survival and the ability of certain bacteria to cause disease
Flagella
135
Flagellum is attached to the bacterial cell body by a
complex structure consisting:
Hook
Basal body
Filament
Motility
136
short curved structure that appears to act as the
universal joint between the motor in the basal
structure and the flagellum
Hook
137
bears a set of rings, one pair in gram positive bacteria and two pairs in gram-negative bacteria
Basal body
138
- long outermost region
- constant in diameter and contains the globular
(roughly spherical) protein flagellin arranged in
several chains that intertwine and form a helix around a hollow core
Filament
139
ability of an organism to move by itself
Motility
140
ARRANGEMENT OF THE FLAGELLA:
Atrichous
Mnotrichous
Amphitrichous
Lophotrichous
Peritrichous
141
without flagellum
Atrichous
142
single flagellum at one end
Mnotrichous
143
single flagellum at both ends
Amphitrichous
144
tuff or group of flagella on one end or both ends
Lophotrichous
145
entire cell surface covered with flagella
Peritrichous
146
- bundles of fibrils that arise at the ends of the cell
beneath an outer sheath and spiral around the cell
- anchored at one end of the spirochete
- have a structure similar to that of flagella
- rotation of the filaments produces a movement of the outer sheath that propels the spirochetes in a spiral motion
- movement is similar to the way a corkscrew moves
through a cork
Axial Filaments
147
- group of bacteria that have unique structure and motility
- movebymeansofAXIAL FILAMENTS OR ENDOFLAGELLA
Spirochetes
148
- group of bacteria that have unique structure and motility
- movebymeansofAXIAL FILAMENTS OR ENDOFLAGELLA
Spirochetes
149
True motility and Brownian Movement are best observed through the ____________________
HANGING DROP METHOD
150
bacteria seem to be going in a definite direction
True Motility
151
bacteria bounce back and forth rapidly due to the bombardment of molecules of water
Brownian movement
152
movement of bacteria toward or away from a
particular stimulus
Taxis
153
WAYS OF DEMONSTRATING MOTILITY IN THE LAB
Hanging Drop Method
SIM
Flagellar staining
Serologic test
Fluorescent Antibody Technique(FAT)
Swarming Phenomenon
Darkfield Microscopy
154
- hairlike, proteinaceous structures that extend from the cell membrane into the external environment; some may be up to 2 μm long
- Hair-like microfibrils usually produced by flagellated Gram-negative bacteria observable by electron microscopy
- serve as adhesins that help bacteria attach to animal host cell surfaces, often as the first step in
establishing infection
- composed ofstructural protein subunits—pilins
PILI (FIMBRIA)
155
Results in short, jerky, intermittent movements
TWITCHING MOTILITY
156
Play a role in bacterial adherence to surfaces thus
contributing to virulence
COMMON PILI OR ORDINARY PILI
157
- serves as the conduit for the passage of DNA from
donor to recipient during conjugation
- present only in cells that produce a protein referred to as the F factor
- F-positive cells initiate conjugation only with F-negative cells, thereby limiting the conjugative process to cells capable of transporting genetic
material through the hollow sex pilus
Sex pilus
158
fimbriae are the site of the main surface antigen---M
protein
Streptococci
159
responsible for the adherence of group A streptococci to epithelial cells of their hosts
Lipoteichoic acid, associated with these fimbriae
160
able to make pili of different antigenic types (antigenic variation)
N. gonorrhoeae
