Intro to Bacteria I (lec 1) Flashcards
Size ranges for:
Bacteria
Viruses
Yeast
Bacteria: 0.2 - 2.0 µm
Viruses: 0.15 - 0.3 µm
Yeast: 4 -20 µm
Bacteria Shapes:
Sphere
Rod
Curved Rod
Spiral Rod, flexible
Spiral Rod, rigid
Short Rod
Variety in one species
Sphere = Coccus
Rod = Bacillus
Curved Rod = Vibrio
Spiral Rod, flexible = Spirochete
Spiral Rod, rigid = Spirillum
Short Rod = Coccobacillus
Variety in one species = Pleomorphic
Cocci Bacterial Arrangements:
Pair
Chain
Grape-like Cluster
Group of Four
Pair = Diplo
Chain = Strepto
Grape-like Cluster = Staphylo
Group of Four = Tetrad
Bacterial Cytoplasmic Membrane composed of?
Does NOT include?
lipid bilayer w/ proteins
No Sterols
What bacteria do not have a Cytoplasmic Membrane?
Mycoplasma spp
Ureaplasma spp
(respiratory, urogenital)
No cell wall means PCN/cephalosporins not effective
Fxns of Cytoplasmic Membranes? (4)
1) Active Transport
2) Synthesis of cell wall precursors
3) Secretion of enzymes and toxins
4) Energy Generation (oxidative phosph thru ETC)
Purpose of Cell Wall?
1) Maintain shape
2) Prevents lysis
(bacteria is hypertonic to body’s hypotonic environment)
Cell Wall made of?
Peptidogylcan:
repeating NAG/NAM disaccharide
peptide crosslinked
G+ bacteria retain which stain?
crystal violet
G- bacteria retain which stain?
safranin
Parts of G- Cell Envelope? (4)
1) glycocalyx
2) outer membrane
3) periplasm
4) cytoplasmic membrane
Outer Membrane of G- made of?
Fxn’l bilayer:
Inner Layer = identical to cytoplasmic membrane
Outer Layer = Phospholipids and Lipopolysaccharides (LPS)
Periplasm of G- made of?
Space b/w cytoplasmic memb and outer memb:
1) Thin peptidoglycan layer
2) Transport proteins
3) Hydrolytic enzymes
Structure of LPS (in G -outer layer)? (3)
1) O antigen
2) Core Polysaccharide
3) Lipid A
O-Antigen of LPS is?
Characteristic?
Used for?
long, linear repeating units of carbs
highly variable (species and strain specific)
identification (serotyping)
Definition:
Antigen
Immunogen
Antigen:
molecule that binds to antibody or antigen receptors on T and B cells
Immunogen:
antigen that initiates immune response (antibody formation by T and B cells)
Core Polysaccharide of LPS is?
Purpose?
branched polysaccharide (9-12 sugars)
links Lipid A to O-Anitgen
Lipid A of LPS found where?
Is?
Does?
outer layer of phospholipid layer of outer memb
Virulence factor - endotoxin
causes clinically significant inflamm response
Definition of Virulence Factor?
structure or substance that enhances pathogenesis
What is SIRS?
Systemic Inflammatory Response Syndrome
causes release of system-wide cytokines (regulatory molecules of immune system)
SIRS clinical manifestation?
2 or more of following:
1) temp > 38º or < 36º
2) tachycardia > 100 bpm
3) tachypnea > 20 bpm
4) leukocytosis > 12,000/mm^3
5) leukopenia < 4,000/mm^3
What is Septic Shock?
What induces Septic Shock?
SIRS + sepsis
sxs (U) fever, hypotension
LPS or endotoxins
Exotoxin is?
Endotoxin is?
exo = secreted protein
endo = structural LPS
G- Cell Envelope Porins are what kind of protein?
Do what?
Channel (span outer memb)
Control diffusion of small molecules: sugars AA metal ions antibiotics
G+ Cell Envelope made of?
Cytoplasmic memb
Peptidoglycan
G+ Cell Wall made of?
Peptidoglycan Teichoic acids (attach bacteria to other CWs and surfaces)
2 types of Teichoic Acids in G+ CW?
Wall Teichoic Acid (WTA):
bound to peptidoglycan
Lipoteichoic Acids (LTA): anchors cell wall to cytoplasmic membrane
G+ bacteria endotoxin is?
teichoic acids - when shed
Acid Fast bacteria Cell Envelope made of? (3)
1) Cell memb
2) Peptidoglycan
3) Mycolic Acid
Mycolic Acid is?
Does?
polymers of long-chain fatty acids (waxy coat),
covalently linked to peptidoglycan (G+ structure)
Makes cell resistant to:
desiccation
some antibiotics
phagocytosis
Acid-Fast Staining process?
Primary Stain: Carbol Fuchsin (red)
Acid-Alcohol Wash: Stays red = acid-fast, turns blue = nonacid-fast
Glycocalyx is made of?
Found where?
What types of bacteria have it?
polysaccharide w/ glycoproteins
outside CW
G+ and G-
Glycocalyx is source of antigens for which 2 bacteria?
K-antigen for e. coli
Vi-antigen for salmonella
Fxn of Glycocalyx? (4)
1) protection against desiccation and phagocytosis
2) barrier to toxic hydrophobic molecules (antibiotics)
3) adheres to cells and surfaces (biofilm)
4) source of immunogenic material for vaccines
Glycocalyx is virulence factor for what type of bacteria?
strep pneumo
w/o Glycocalyx it is avirulent
2 forms of Glycocalyx?
1) slime layer
2) capsule
Properties of Slime Layer? (3)
1) loose, non-uniform
2) form biofilm
3) for diffuse
Properties of Capsules? (2)
1) rigid, uniform
2) closely surrounds cell
