Lecture 1/2 - Introduction to Bacteria Flashcards
1
Q
What is PCR?
A
Polymerase Chain Reaction
2
Q
How does PCR relate to Koch’s postulates?
A
Isolation of microbe along with identification
3
Q
What is the ID based on when PCR is used?
A
NA amplification
Amplification of gene sequences
Sequence must be KNOWN!
4
Q
What is a pro to using PCR?
A
Growth in pure culture is not needed.
5
Q
What are the two components to a bacteria’s name?
A
Genus + Species
6
Q
What is another component to the name of some bacteria?
A
Serotype
7
Q
What are the categories for bacterial morphology?
A
Size
Shape
Arrangement of cells
8
Q
What is the average range when it comes to the size of a bacteria?
A
0.2 to 2.0 um in diameter
9
Q
What is the order (small to large) of the following:
Bacillus - Spirochete - Coccus
A
Coccus - Bacillus - Spirochete
10
Q
Describe coccus.
A
Spheres/round
11
Q
Describe bacillus.
A
Rod
12
Q
Describe vibrio.
A
Curved rod
13
Q
What are the two subtypes of spiral?
A
Spirillum + Spirochete
14
Q
Describe Spirillum.
A
Rigid, sprial-shaped rod
15
Q
Describe spirochete.
A
Flexible, thin, spiral-shaped rod
16
Q
Describe coccobacillus.
A
Short rod
17
Q
What is pleomorphic?
A
One species but several different kinds of shapes
18
Q
What type of bacteria are arrangements most likely to describe?
A
Coccus
19
Q
What is strepto?
A
Chain
20
Q
Describe staphylo?
A
Grape-like cluster
21
Q
What are the three major parts to the cell envelope of a bacteria?
A
Glycocalyx + Cell wall + Cytoplasmic membrane
22
Q
What are the two things that a glycocalyx can form?
A
Capsule + Slime layer
23
Q
What is the glycocalyz made from?
A
Polysaccharides + glycoproteins
24
Q
Where is the glycocalyx located?
A
Outside of the cell wall
25
What special structures does the glycocalyx add to bacteria like e. coli and salmonella?
K + V antigen
26
What are the K and Vi antigen found on the glycocalyx?
Used for serotyping
27
What is the function of the glycocalyx?
Protects from drying out, from phagocytosis, and toxins
Promotes adherence to host cell = biofilm
Can be a virulent factor in some bacteria
28
What bacteria is virulent when a glycocaylx is present?
Streptococcus pneumoniae
29
What is an antigen?
Molecule that binds to Ab or Ag receptors on T/B cells
30
What is an immunogen?
Antigen that causes an immune response
31
What are the characteristics of the slime layer?
Loose, non-uniform
| More diffuse
32
What are the characteristics of a capsule?
Rigid, uniform and closely surrounds cell
33
What is used to ID a capsule?
Quellung test - ID's by serotyping
34
What is clinically important about the cell wall of a bacteria?
Tells you if it is gram +/- or acid fast. tells you what kind of antibiotic you should try
35
What two genera do not have a cell wall?
Mycoplasm + Ureaplasm
36
Where is the cell wall located?
Outside cell membrane
37
What is the function of the cell wall?
Maintain shape
| Prevent uptake of too much H2O
38
Why is uptake of H2O a big concern?
Bacteria live in a hypotonic environment, water is constantly trying to get into cell due to concentration gradient.
39
What is the main component of the cell wall?
Peptidoglycan
40
What is the backbone of the cell wall made of?
Repeating disaccharides (NAG-NAM)
41
What links the backbone of the cell wall in bacteria?
Transglycosylation via glucosidases
42
What does PEP attach to in the cell wall?
NAM
43
What is crosslinked in the cell wall?
PEP - Pentapeptide
44
What crosslinks PEP?
Transpeptidation via transpeptidase
45
What PEP structure is special in gram-positive bacteria?
Pentaglycine bridge
46
What bacteria has pentaglycine bridge?
Staphylococcus spp.
47
What is the primary stain for gram staining?
Crystal violet
48
What is the counterstain for gram staining?
Safranin
49
What color is gram-negative?
Pink/Red
50
What color is gram-positive?
Blue/Purple
51
How many layers of peptidoglycan does gram-negative have?
~2
52
How many layers of peptidoglycan does gram-postive have?
> 25 layers
53
What are the major layers of the gram-negative bacteria?
Glycocalyx - Outer membrane - Periplasm space w/ cell wall - Cytoplasmic membrane
54
What is the periplasmic space?
```
In Gm(-)
Space btwn cytoplasmic membrane + outer membrane
```
55
What does the periplasmic space contain?
Thin peptidoglycan layer
Transport proteins
Hydrolytic enzymes
56
What are the major requirements for Koch's Postulates?
Requires growth in pure culture
| First method for isolation/identification of bacterial cause of disease
57
Where is the outer membrane located?
External to periplasmic space
58
How many layers to the outer membrane?
Two - Inner and Outer
59
What is the structure of the inner layer of the outer membrane?
Identical to the cytoplasmic membrane
60
What is the structure of the outer layer of the outer membrane?
this is what contains the endotoxin aka LPS
| Most gram-negative bacteria
61
What is the function of the outer membrane?
May impede phagocytosis
| Protective permeability to large molecules + hydrophobic compounds
62
What are the three components of LPS? Where is LPS contained again?
```
Polysaccharide core
Lipid A
O polysaccharide (O-antigen)
```
Found on the Outer layer of the outer membrane
63
What is the structural characteristics of the O antigen?
Long, linear repeating units of carbohydrates
| Highly variable
64
What is clinically important to know about the O-antigen when it comes to it being highly variable?
Gives it antigenic variation = it can change the O antigen on it's surface allowing it to evade the immune system and stay safe in host longer.
65
What is the "function" of the O antigen?
Antigen/Immunogen
| Helps us ID the bacteria
66
What is antigenic variation?
Change in genetic codings for a structural proteins, leading to the creation of a new bacterial antigen.
67
What is the structure of the core polysaccharide?
Branched polysaccharide that is 9 to 12 sugars long
| Contain KDO
68
What is KDO, found within LPS core?
Ketodeoxyoctonoix acid, a unique sugar found in LPS
69
Where is Lipid A found on LPS?
Attacted to the outer phospholipid layer of the outer membrane
70
What is a virulence factor?
Structure or substance that enhances the pathogenesis of the microbe
71
What is the basic description of an Exotoxin?
Secreted proteins
72
What is the basic description of an Endotoxin?
Structural lipopolysaccharide
73
What kind of bacteria are porins found in?
Gram-negative
74
What are the structural components of porin?
3 part protein = channel forming, span out membrane
75
What is the function of porins?
Control diffusion of small molecules
For example: Sugars, metal ions, AB's
76
What are the special characteristics only found in the cell wall of a gram-positive bacteria?
Teichoic + Lipotheichoic acid within the huge layer of peptidoglycan
77
What is the importance of Teichoic + Lipoteichoic acids?
Virulence factors of gram-positive bacteria
78
What makes up the cell wall of a gram-positive bacteria?
Cytoplasmic membrane
-- and --
Peptidoglycan
79
What is teichoic acid?
Adhesins; polymers of ribitol phosphate/glycerol phosphate
| Covalently linked to muramic acid
80
What is the function of teichoic acids?
Help stitch together the huge peptidoglycan layer
81
What is lipoteichoic acids?
LTA; teichoic acid anchored to cytoplasmic membrane
82
What do antimicrobial cell wall inhibitors tend to focus on?
Transpeptidation
| Cell wall synthesis
83
What is transpeptidation in regards to the peptidoglycan of the cell wall?
The cross-linking of these molecules
84
What is the function of a lysozyme?
Degrades glycan backbone - breaks the bond between NAG + NAM
85
What is a lysozyme a component of?
Lytic enzyme of the innate immune system
86
Where in the body are lysozymes found?
Tears - Saliva - Mucus - Lysosomes of WBC
87
What is within the cell envelope of an acid-fast bacteria?
Cell membrane
Peptidoglycan
Mycolic acid layer
88
Where is the mycolic acid layer found?
Outer layer of outer membrane
| Covalently linked to peptidoglycan
89
What type of bacteria is going to be acid-fast?
Gram-positive
90
What does the mycolic acid do?
Allows cell to resist desiccation + some AB's + Phagocytosis by creating a waxy layer.
91
What is the primary stain of an acid-fast stain?
Carbolfuschin
92
What is the counterstain of the acid-fast stain?
Methylene blue
93
What color does an acid fast bacteria stain?
Red
94
What is an example of an acid fast bacteria given in lecture?
Mycobacterium
95
What is missing from the cytoplasmic membrane of bacteria?
Sterols
96
What is the function of the cytoplasmic membrane?
Active transport
Synthesis of cell wall material
Secretion of enzymes/toxins
ETC
97
What are the four major groupings of bacteria in regards to their staining abilities?
Gm (-)
Gm (+)
Acid-Fast
No cell walls
98
What are the two general external structures of a bacteria?
Flagella + Fimbria/Pilus
99
What is the structure of the flagella?
Filamentous protein structures that are anchored to the cell membrane
100
What is the function of the flagella?
Motility + taxis
| Source of H antigen
101
What does polar refer in regards to external structure location?
Found on one or both ends
102
What is peritrichous in regards to the location of external structures on a bacteria?
Lateral, over entire cell surface
103
What is the structure of fimbria/pilus?
Associated w/ cell membrane, hair-like protein structures
104
How are pili arrange on the bacteria?
Peritrichously
105
What is the function of pili?
Promote adherence to host cell
| Act as sex pilus
106
What exactly is a sex pilus?
Structure on SOME bacteria for congugation
107
What are the four basic internal structures of a bacteria?
Nuclear region
Ribosomes
Inclusion bodies
Endospores
108
What is the structure of the nuclear region in a bacteria?
NO nuclear membrane
| Area that contains chromosomal DNA
109
What is the benefit of having no nuclear membrane in a bacteria?
Can synthesize protein quicker via coupled transcription and translation
110
What are the two basic types of bacterial DNA?
Chromosome + Plasmid
111
What is the structure of a bacterial chromosomal DNA?
dsDNA
CCC
Supercoiled
Haploid
112
What is the downside of being a hapliod?
No extra copy, mutations are expressed easily
113
What is the normal function of a plasmid?
Not essential for survival, encodes for things like AB resistance and toxins
114
What is the basic mechanism by which the plasmid is regulated?
Replicates separately from bacteria, but does use it's machinery
115
What are inclusion bodies?
Storage for energy molecules in a bacteria
116
What is the structure of an inclusion body
Nonunit, membrane
117
What tends to produce endospores?
Gram-positive bacteria
118
What is an endospore?
Dormant protective stage of bacteria
119
What is the endospore made of?
Keratin = Coat
| Dipicolinic acid = internal
120
What are the two gram-positive pathogenic genera that make endospores?
Bacillus + Clostridium
