Unit 2 Flashcards
(114 cards)
1
Q
Domain bacteria are
A
Single-celled organisms
Prokaryotic
Ubiquitous
2
Q
Always include what characteristics when describing bacteria
A
Morphology (shape)
Size of individual cell
Arrangement
Gram stain result
3
Q
Cocci (singular coccus)
A
Spheres
4
Q
Bacilli (singular bacillus)
A
Rods or filaments
5
Q
Coccobacilli (singular coccobacillus)
A
Short plump rods, almost ovals
6
Q
Vibrios
A
Comma-shaped (curved rod)
Singular
7
Q
Spirilla
A
Rigid helix
Have flagella for motility
Singular (less common in chains)
8
Q
Spirochetes
A
Corkscrew (telephone cord)
Motility: flagella to wind or by spring type creeping
Singular
9
Q
Pleiomorphism
A
Having more than one shape or form
10
Q
The variability of bacteria can depend on
A
The health of bacteria during various stages of growth, or if growth under different conditions
11
Q
True or false
Always measure individual cells
A
True
12
Q
What unit are measurements of bacteria taken in
A
Microns
13
Q
How to measure cocci
A
Take the diameter of the sphere
14
Q
How to measure bacilli
A
Give width and length of each rod
15
Q
How to measure spirilla, spirochetes, and filamentous
A
Give length while it is still curved/folded
16
Q
True or false
Always measure the longest bacterium
A
FALSE
measure the most commonly represented size
17
Q
Arrangement of cocci: singular
A
Coccus
18
Q
Arrangement of cocci: diplococci
A
Pairs
19
Q
Arrangement of cocci: streptococci
A
Chains
20
Q
Arrangement of cocci: staphylococci
A
Grape like clusters
21
Q
Arrangement of cocci: tetrads
A
4 in a square
22
Q
Arrangement of cocci: sarcinae
A
8 coccus in a cube
23
Q
Arrangement of bacilli: bacillus
A
Singles
24
Q
Arrangement of bacilli: diplobacilli
A
Pairs (end to end)
25
Arrangement of bacilli: streptobacilli
Chains of 3 or more (end to end)
26
Arrangement of bacilli: palisades
“Picket fence” arranged side by side
27
Bacteria colony
Mound of bacteria cells visible to the naked eye
28
True or false
| All cells in a bacteria colony are derived from a single bacteria cell
True
29
Different bacteria produce colonies with distinct shapes and colors when grown in vitro, what do these characteristics help identify
The genus
30
What is a colony forming unit
The single bacterium that started a colony
31
True or false
| All the cells in a colony are identical
True
32
True or false
| Each colony represents one colony forming unit
True
33
A bacterial cell
Unicellular
Prokaryotic
Lack membranes
34
Cytoplasmic membrane/cell membrane/ plasma membrane
Thin flexible membrane that surrounds EVERY living cell
Selectively permeable
Contains carbohydrates, proteins and cholesterol
35
What is the main component of a cytoplasmic membrane
The phospholipid bilayer
36
What are the proteins a cytoplasmic membrane contains (5)
```
Channels and transporter proteins
Signal receptor proteins
Metabolic proteins
Attachment proteins
Surface antigen proteins
```
37
What are channel and transporter proteins in a cytoplasmic membrane
They move substances in and out of the cell
38
How do some antibiotics enter cells
By targeting bacteria with transporter and channel proteins to get into the cell
39
What are signal receptor proteins in cytoplasmic membranes
Proteins that bind to signals from the environment
40
What are some things a signal receptor protein may tell a the bacterium to do
Start or stop replicating
Move away from harm
Produce enzymes for metabolism
Produce enzymes to inactivate some antibiotics
41
What are metabolic proteins in cytoplasmic membranes
Energy producing proteins located along the folds in the cytoplasmic membranes (because bacteria do not have mitochondria which are membrane bound organelles)
42
Mesosomes
The folds or invagination on cytoplasmic membranes
43
What are attachment proteins on cytoplasmic membranes
Attach bacterium to specific cells in the host
(Certain bacteria can only attach to certain cells)
Essential for infection to occur
44
What are surface antigens on cytoplasmic membranes
Any protein on the surface of the bacteria that can be recognized by the host’s immune system
“Molecular ID tags”
45
What can surface antigens aid in when staining
Can be used to identify different strains of the same species
46
Functions of the cytoplasmic membrane (6)
Encloses cytoplasm
Barrier function
Regulates movement of molecules in/out of the cell
Interacts with environment via signal receptors
Site for energy production
Attachment
47
Cytoplasm
The fluid that fills the cell (60-70%)
48
Where is the cytoskeleton
Molecular scaffold that spans across the cytoplasm
49
true or false
| the cytoplasm is metabolically active
True
50
Ribosomes
Complex structures consisting of protein and ribosomal RNA
Site or protein synthesis (where RNA is read to assemble proteins)
51
What is the process of translation
Where RNA is read and used to assemble proteins
52
Chromosomal DNA
A single, circular strand of DNA that contains all essential genes
53
True or false
| There are fewer genes in chromosomal DNA in eukaryotic cells
True
54
Where is chromosomal DNA located
In the nucleoid
55
What are plasmids
“Extra” circular pieces of DNA containing 1-2 genes (not a part of chromosomal DNA) (located outside the nucleoid)
56
Are the genes located on plasmids essential to life
No, but they are beneficial to survival by providing advantages
57
What are some advantages of some genes in plasmids
Proteins that provide antibiotic resistance
Genes for specific toxins or attachment proteins
Genes that enable bacteria to produce capsules
58
Do all bacteria have plasmids
No, some have one, more than one or none
59
Do plasmids replicate independently of chromosomal DNA
Yes
60
True or false
| Plasmids are very resistant to degradation and can even survive after the bacteria have been destroyed
True
61
What are 3 ways plasmids are transferred between cells
Replication
Transformation
Conjugation
62
Transfer of plasmids via Replication
When a bacteria cell divides, plasmids also duplicate and an equal number of plasmids are given to the daughter cell
63
Transfer of plasmids via transformation
Where the cell membrane opens up and allows the cell to take up a plasmid from the environment from a bacteria that has died but the plasmid survived
64
Transfer of plasmids via conjugation
When the direct contact between 2 bacteria cells through the creation of a temporary bridge allows the transfer of plasmids
65
The cell wall surrounds
The cytoplasmic membrane
66
Categories of cell walls
Gram positive
Gram negative
Acid fast
(Based on staining properties)
67
The type of cell wall helps identify
The genus
68
Functions of the cell wall
Maintains shape
Protects from lysis Due to osmotic pressure
Protects from toxic materials
Attachment
Prevents phagocytosis by WBCs in the immune system
69
Two ways to break down the cell wall
Lysozymes: breaks linkages of cell wall
Beta-lactames: class of antibiotics that prevent proper synthesis of the cell wall
70
Penicillin and cephalosporins are in what class of antibiotics
Beta-lactames
71
Cell wall structure and components
Primary component: peptidoglycan (2 different polysaccharides linked together)
Peptide cross links: short peptide chains that link peptidoglycans together
72
Gram positive wall
Thick: 40-90% of cell mass
20-80 layers of peptidoglycan Joined by peptide cross links
73
What is transpeptidase
Enzyme required to make the peptide cross links in cell walls
74
What is teichoic acid in the cell wall
Long molecules that help embed the cell wall to the cytoplasmic membrane
Also on the surface of the cell to help attach bacteria to other bacteria
75
Why are gram positive bacteria susceptible to the beta-lactam class of antibiotics?
These antibiotics bind to and block the function of transpeptidase enzyme and prevent the formation of peptide cross links between peptidoglycan strands
(Makes susceptible to osmotic pressure lysis)
76
Gram negative cell wall
Thin: 10% of cell mass
| Only 1-2 layers of peptidoglycan
77
Layers of a gram negative cell wall
Peptidoglycan layer: 1-2 layers, closest to cytoplasmic membrane
Outer membrane: 2 layers of lipids (inner layer is a single sheet of phospholipids, outer layer is a single sheet of lipopolysaccharides LPS)
Periplasmic space: space between the cytoplasmic membrane and outer membrane (peptidoglycan layer is in this space)
78
What are lipopolysaccharides
The molecule that makes up the outermost layer of a gram negative cell wall (part of the outer membrane)
79
What are lipopolysaccharides important for?
To bacteria: establishing infection
To host: to fight infection
80
What are the 3 parts of a lipopolysaccharide
```
O-antigen
Core polysaccharide
Lipid A (endotoxin)
```
81
What is the O-antigen on lipopolysaccharides
Repeats of polysaccharide units (hydrophilic)
Smooth: bacteria with long chains
Rough: bacteria with short or no chain
82
True or false
| Some species or strains are distinguishable by the sugar molecule in their o-chain (gram negative wall)
True
83
Why are the O antigens on gram negative cell walls important for bacteria to establish infection?
WBCs unable to grab onto smooth bacteria
Aid in attaching to epithelial cells
Some bacteria can alter the sugars that make the O-antigen: can evade the immune system
84
The immune system can recognize sugars in the O antigen when fighting infection, what happens
The immune system targets these for destruction
The O chain will trigger non-specific inflammation
85
Lipid A (AKA endotoxin)
The tail of lipopolysaccharides made of lipid chains
They are the same in all gram negative bacteria
Hydrophobic
Holds lipopolysaccharide in place
86
True or false
| Lipid A is one of the strongest activators of inflammation
True
87
Endotoxic shock
Condition where excess inflammation causes blood vessels to dilate, drop blood pressure, and cause systemic shock
Caused by a release of large amounts of lipid A during gram negative infection
Can be fatal
88
Why can endotoxic shock never happen in gram positive bacteria
Gram positive cell walls do NOT contain lipopolysaccharides (which have lipid A) only gram negative cell walls do
89
Why do some bacteria do not gram stain?
They have no cell wall structures similar to gram positive and negative walls
90
Acid fast bacteria
Their cell wall is similar to gram positive but contain large amounts of mycolic acid (waxy) (long chain of fatty acids)
Ex. Mycobacterium
91
Mycoplasma
Do not have cell walls
Plasma membrane more resistant to osmotic pressure
Very pleiomorphic
92
What does the Periplasmic space contain
Proteins to digest macronutrients
Proteins to break down toxic compounds before the cross the plasma membrane
Synthesis and storage of pathogenic factors
93
Flagella
Threadlike projections that allow motility
All spirochetes and spirilla have them
94
What does the immune system recognize in flagella
The proteins that make the flagella (act as antigens)
95
Location and number of flagella on a bacterium determine
Type and speed of movement
96
Bacteria with many flagella that move together tend to be
Faster
97
True or false
| You can see the flagella on bacteria
False
| But you can see fast motility
98
Benefits of motility on bacteria
Can move towards supportive environments
Can move away from harmful substances
99
Flagella movement
Fastest
| Flagella acts as a propeller to swim through lipids
100
Spirochetes motility
Corkscrew motion due to Periplasmic flagella (specific to Spirochetes)
101
Twitching motility
Mediated fimbriae, crawling on surface or through lipids
102
Gliding motility
Pushed by slime made by the bacteria
103
Chemotaxis
Process of identifying and then moving away from a chemical via receptors that tell the bacteria what to do
104
Positive chemotaxis
Moving towards attractants
105
Negative chemotaxis
Moving away from repellants
106
Fimbriae (singular fimbria)
Short, thin, hair like protein structures that extend out of the cell wall
Primary function: attachment to surfaces
107
Pili
Very large protein structures that extend from cell wall
2 functions:
Attachment
Forms connection during conjugation
108
Capsules
Polysaccharide secreted around the cell wall
Sugar units well organized
Attached to cell, not easily removed
Primary functions:
Resistance/protection (from drying out)
Attachment
109
Slime layers
Polysaccharide secreted around the cell wall
Sugar units are not uniform, loose coating, easily removed
```
Primary functions:
Resistance/protection
Attachment
Motility
formation of biofilms
```
110
Advantages of capsules and slime layers (5)
Resistance to phagocytosis and bacteriophages
Protection from drying out
Protects from detergents and antibiotics
Attachment
Motility (slime)
111
Biofilms
Communities of bacteria (and yeast) embedded in a matrix that attach to a surface
Single or hundreds of different species of bacteria
Matrix sticks microbes to one another and onto a surface (usually moist)
112
4 steps in biofilm formation
1) cell attachment to surface (by receptors, flagella, fimbriae)
2) cell produces exopolysaccharides (outside cell)
3) biofilm matures (increase in size and number)
4) cells from biofilm disperse and can reattach elsewhere
113
Where are biofilms common to?
```
Standing water
Rough surfaces
Surgical implants
Catheters
Heart valves
Teeth
```
114
Biofilms are self-sustaining so they are
Hard to treat with antibiotics or disinfectants
