1.1 Flashcards
1
Q
Microorganisms and the human body (5)
A
bacteria viruses fungi protozoa helminths (worms)
2
Q
microbiome (4)
A
bacteria
viruses
fungi
protozoa
3
Q
Parasitic organisms
A
Symbionts that harm or live at the expense of their host
4
Q
Commensal organisms
A
Normal microbiota - microbes frequently found on or within
the bodies of healthy persons
5
Q
Infection
A
–growth and multiplication of parasite on or within host
6
Q
Infectious disease
A
–disease resulting from infection
7
Q
Pathogen
A
–any parasitic organism that causes infectious disease
8
Q
primary (frank) pathogen –
A
causes disease by direct
interaction with host
9
Q
opportunistic pathogen –
A
causes disease only under certain
circumstances
10
Q
Pathogenicity
A
–ability of parasite to cause disease
11
Q
Virulence factor
A
- any component of a pathogenic microbe that is required for
or that potentiates its ability to cause disease
12
Q
steps in infectious disease (6)
A
encounter entry spread multiplication damage outcome
13
Q
Encounter (3)
A
Exogenous
Endogenous
Congenital
14
Q
- Entry (2)
A
ingress
penetration
15
Q
Ingress:
A
inhalation, ingestion
16
Q
Penetration:
A
microbes pass through epithelia directly (via
attachment and internalization), insect bites, cuts
and wounds, organ transplants and blood
transfusions
17
Q
Spread (3)
A
lateral propagation versus dissemination
anatomical factors
active participation by microbes
18
Q
Multiplication (2)
A
environmental factors (e.g. temperature) subversion of host defenses
19
Q
Mucormycosis (fungal infection) in
rhinocerebral form, almost always with (2)
A
hyperglycemia and metabolic acidosis
20
Q
Damage (2)
A
direct damage
immune response
21
Q
Outcome (3)
A
microbe wins, host wins, or they learn to coexist
22
Q
Normal microbiota-
A
microbes frequently found on or within
the bodies of healthy persons
commensal organisms
23
Q
Colonization by bacteria occurs rapidly after
A
birth
24
Q
— of bacterial species are part of the normal flora.
A
Thousands
25
The Human Microbiome
the collection of all the microorganisms living
in association with the human body
eukaryotes, archaea, bacteria and viruses
26
Bacteria in an average human body number --- times more than human cells
ten
contain a total of about 1000 more genes than are present in the human genome because of their small size bacteria make up only about 1-3% of our body mass
2 to 6 pounds of bacteria in a 200-pound adult
27
Bacteria in the microbiome of a healthy individual are essential for maintaining ---
health
28
Bacteria in the microbiome of a healthy individual are essential for maintaining health (6)
produce some vitamins that we do not have the genes to make
break down our food to extract nutrients we need to survive
teach our immune systems how to recognize dangerous invaders
produce helpful anti-inflammatory compounds that fight off other disease-causing microbes
occupy space to crowd out disease-causing microbes
detoxification of carcinogens but sometimes are the source of carcinogen production
29
Changes in the composition of our microbiomes correlate with
numerous disease states
source of infection
manipulation of these communities could be used to treat disease
30
Locations in body with largest amounts of bacteria (5)
```
skin (especially moist areas)
respiratory tract (nose and oropharynx)
digestive tract (mouth and large intestine)
urinary tract (anterior parts of urethra)
genital system (vagina)
```
31
Other body locations have small numbers of bacteria.
Remainder of respiratory and digestive tracts
32
Some body locations are sterile. (4)
blood, cerebrospinal fluid, synovial fluid, deep tissues
33
Transient vs. resident organisms
34
Pathogenicity/virulence also depend on the
host
| Definition of pathogen not so certain
35
periodontitis -
overgrowth of particular bacteria in gingival
| crevices
36
pneumonia -
defenses lowered and microaspirations of
| pneumococci
37
catheter-associated infections -
staphylococci
38
Oral flora includes (4)
bacteria (and archeae)
fungi
protozoa (eukaryotes)
viruses
39
~--- different species of bacteria are estimated to
| be present in the oral cavity
700
40
Oral habitats (5)
```
buccal mucosa
dorsum of tongue
tooth surfaces
crevicular epithelium
dental appliances
```
41
Issues for microbial cells (3)
Nutritional fluxes
Maintaining occupancy
Resistance to damage
42
anatomical features that create areas that are
| difficult to clean (4)
- shape and topography of teeth
e. g. fissures
- malalignment of teeth
- poor quality of restorations (e.g. fillings and bridges)
- non-keratinized sulcular epithelium
43
saliva fxns (7)
mixture of inorganic ions
organic constituents
salivary pellicle
source of food
promotes aggregation of bacteria, facilitating their clearance from mouth
inhibits growth of microbes by non-specific defense factors
maintains pH
44
```
saliva
organic constituents (2)
```
proteins
| glycoproteins (e.g. mucin)
45
salivary pellicle
promotes adhesion of bacteria on tooth surfaces
| organic components form a coating on tooth surfaces
46
gingival crevicular fluid (5)
```
flushing microbes out of crevice
source of nutrients for microbes
maintains pH
specific and non-specific defense factors
phagocytosis
```
47
phagocytosis
| --- main phagocyte
neutrophils
48
microbial factors (4)
competition for adhesion receptors
toxin production
metabolic end products
coaggregation
49
metabolic end products
negative vs. positive effects
50
local pH
| will vary with diet as a result of
bacterial metabolism
51
redox potential
a measure of oxygen levels in locality
52
Factors modulating oral microbial growth (9)
```
anatomical features that create areas that are difficult to clean
saliva
GCF
microbial factors
local pH
redox potential
antimicrobial therapy
diet
iatrogenic factors
```
53
iatrogenic factors
dental scaling
54
--- are an absolute requirement for
| all living organisms
membranes
55
plasma membrane encompasses the ---
cytoplasm
56
some prokaryotes also have
internal
membrane systems
most DO NOT
57
The Plasma Membrane contains (2)
lipids and proteins
– lipids usually form a bilayer
– proteins are embedded in or associated with lipids
58
PM characteristics (4)
highly organized, asymmetric, flexible, and
| dynamic
59
```
The asymmetry of most
membrane lipids
polar ends (2)
nonpolar ends (2)
```
```
• polar ends
– interact with water
– hydrophilic
• nonpolar ends
– insoluble in water
– hydrophobic
```
60
peripheral proteins
– loosely associated with the membrane and
| easily removed
61
integral proteins
– embedded within the membrane and not easily
| removed
62
Functions of the plasma
| membrane (4)
• separation of cell from its environment
• selectively permeable barrier
• location of crucial metabolic processes
• detection of and response to chemicals in
surroundings with the aid of special
receptor molecules in the membrane
63
selectively permeable barrier (2)
– some molecules are allowed to pass into or out
of the cell
– transport systems aid in movement of
molecules
64
Inclusion Bodies
• granules of organic or inorganic material
| that are stockpiled by the cell for future use
65
Inclusion Bodies
| some are enclosed by a
single-layered
membrane
– membranes vary in composition
– some made of proteins; others contain lipids
66
Ribosomes
• complex structures consisting of protein and
| RNA
67
Ribosomes site of
protein synthesis
68
Ribosomes
| p vs e
prokaryotic are smaller than eukaryotic ribosomes
69
– prokaryotic ribosomes =
70S
70
– eukaryotic ribosomes =
80S
71
S =
Svedburg unit
72
The Nucleoid (3)
• irregularly shaped region
• location of chromosome
– usually 1/cell
• not membrane bound
73
```
In actively
growing cells,
the nucleoid
has projections;
these probably
contain
```
DNA
being actively
transcribed
74
The prokaryotic chromosome (3)
• a closed circular, double-stranded DNA
molecule
• looped and coiled extensively
• nucleoid proteins probably aid in folding
75
– nucleoid proteins differ from ---
histones
76
some prokaryotes have > - chromosome
1
77
some prokaryotes have chromosomes
| composed of
linear double-stranded DNA
78
a few genera have --- nucleoids
membrane-delimited
79
Plasmids (4)
```
• usually small, closed circular DNA
molecules
• exist and replicate independently of
chromosome
• not required for growth and reproduction
• may carry genes that confer selective
advantage (e.g., drug resistance)
```
80
The Prokaryotic Cell Wall
• rigid structure that lies
just outside the plasma
membrane
81
Functions of cell wall (4)
* provides characteristic shape to cell
* protects the cell from osmotic lysis
* may also contribute to pathogenicity
* may also protect cell from toxic substances
82
Bacteria are divided into two major groups
based on the response to Gram-stain
procedure
– gram-positive bacteria stain purple
| – gram-negative bacteria stain pink
83
• staining reaction due to
cell wall structure
84
Periplasmic space
• gap between plasma membrane and cell
wall (gram-positive bacteria) or between
plasma membrane and outer membrane
(gram-negative bacteria)
85
periplasm
– substance that occupies periplasmic space
86
Periplasmic enzymes
| • found in
periplasm of gram-negative
| bacteria
87
Periplasmic enzymes fxn (4)
– nutrient acquisition
– electron transport
– peptidoglycan synthesis
– modification of toxic compounds
88
Exoenzymes (2)
• secreted by gram-positive bacteria
• perform many of the same functions that
periplasmic enzymes do for gram-negative
bacteria
89
Peptidoglycan Structure (3)
• important component of both gram-positive
and gram-negative bacteria
• polysaccharide formed from peptidoglycan
subunits
• two alternating sugars form backbone
90
two alternating sugars form backbone (2)
– N-acetylglucosamine
| – N-acetylmuramic acid
91
Gram-Positive Cell Walls (2)
```
• composed primarily
of peptidoglycan
• also contain large
amounts of teichoic
acids
```
92
teichoic acids
• polymers of glycerol
or ribitol joined by
phosphate groups
93
Gram-Negative Cell Walls (3)
• consist of a thin layer of peptidoglycan
surrounded by an outer membrane
• outer membrane composed of lipids,
lipoproteins, and lipopolysaccharide (LPS)
• no teichoic acids
94
Braun’s lipoproteins connect outer
| membrane to ---
peptidoglycan
95
Adhesion sites (2)
– sites of direct contact (possibly true membrane
fusions) between plasma membrane and outer
membrane
– substances may move directly into cell through
adhesion sites
96
Lipopolysaccharides (LPSs)
| • consist of three parts
– lipid A
– core polysaccharide
– O side chain (O antigen)
97
Importance of LPS (4)
• protection from host defenses (O antigen)
• contributes to negative charge on cell
surface (core polysaccharide)
• helps stabilize outer membrane structure
(lipid A)
• can act as an endotoxin (lipid A)
98
Other characteristics of outer
membrane
• more permeable than plasma membrane due
to presence of
porin proteins and transporter
| proteins
99
porin proteins form channels through which
small molecules (600-700 daltons) can pass
100
Capsules, Slime Layers, and SLayers
| • layers of material lying --- the cell wall
outside
101
capsules (2)
* usually composed of polysaccharides
| * well organized and not easily removed from cell
102
slime layers (1)
• similar to capsules except diffuse, unorganized and
| easily removed
103
glycocalyx (2)
– network of polysaccharides extending from the
surface of the cell
– a capsule or slime layer composed of
polysaccharides can also be referred to as a
glycocalyx
104
More functions of outer membrane (4)
• protection from viral infection or predation
by bacteria
• protection from chemicals in environment
(e.g., detergents)
• motility of gliding bacteria
• protection against osmotic stress
105
fimbriae (2)
– short, thin, hairlike, proteinaceous appendages
• up to 1,000/cell
– mediate attachment to surfaces
106
sex pili (2)
```
– similar to fimbriae except longer, thicker, and
less numerous (1-10/cell)
– required for mating
```
107
• monotrichous –
one flagellum
108
• polar flagellum –
flagellum at end of cell
109
amphitrichous –
one flagellum at each end
| of cell
110
lophotrichous –
cluster of flagella at one or
| both ends
111
peritrichous –
spread over entire surface of
| cell
112
Flagellar Ultrastructure
| • 3 parts
– filament
– basal body
– hook
113
The Bacterial Endospore (3)
• formed by some bacteria
• dormant
• resistant to numerous environmental
conditions
114
resistant to numerous environmental
| conditions (4)
– heat
– radiation
– chemicals
– desiccation
115
An Overview of Eukaryotic Cell Structure (4)
```
• membrane-delimited nuclei
• membrane-bound organelles that
perform specific functions
• more structurally complex than
prokaryotic cell
• generally larger than prokaryotic
cell
```
116
The Endoplasmic Reticulum
```
irregular network of
branching and
fusing membranous
tubules and
flattened sacs
(cisternae – s.,
cisterna)
```
117
rough (granular) ER (2)
– ribosomes attached
| – synthesis of secreted proteins by ER-associated ribosomes
118
smooth (agranular) ER (2)
– devoid of ribosomes
| – synthesis of lipids by ER-associated enzymes
119
Functions of ER (3)
– transports proteins, lipids, and other materials within cell
– major site of cell membrane synthesis
– synthesis of lysosomes
120
The Golgi Apparatus
• membranous organelle
made of cisternae
stacked on each other
121
dictyosomes
– stacks of cisternae
122
The Golgi Apparatus
| • involved in (3)
modification,
packaging, and
secretion of materials
123
lysosomes (2)
– membrane-bound vesicles
– contain hydrolytic enzymes needed for
digestion of macromolecules
124
endocytosis
– uptake of solutes or particles by enclosing them
in vesicles or vacuoles pinched off from the
plasma membrane
125
• Phagocytosis –
particles or bacterial cells
126
• Pinocytosis -
solutes
127
Mitochondria (2)
```
• site of tricarboxylic
acid cycle activity
• site where ATP is
generated by
electron transport
and oxidative
phosphorylation
```
128
Mitochondrial structure (3)
* outer membrane
* inner membrane
* matrix
129
inner membrane (2)
– highly folded to form cristae (s., crista)
– location of enzymes and electron carriers for electron transport and
oxidative phosphorylation
130
matrix (2)
– contains ribosomes, mitochondrial DNA, and large calcium
phosphate granules
– contains enzymes of the tricarboxylic acid cycle and the β- oxidation pathway for fatty acids
131
nucleus
– membrane-bound structure that
| houses genetic material of cell
132
chromatin (3)
– dense fibrous material within nucleus
– contains DNA
– condenses to form chromosomes
during cell division
133
nuclear envelope (2)
– double membrane structure that
delimits nucleus
– penetrated by nuclear pores
134
pores allow materials to be
transported into or out of nucleus
135
The molecular unity of
| prokaryotes and eukaryotes (3)
* same basic chemical composition
* same genetic code
* same basic metabolic processes
