M3: Biology of Pathogens/Bacteria I Flashcards
Major divisions of pathogens (3)
viruses
prokaryotes (no nucleus): Bacteria and Archaea (no proven role in human disease-maybe periodontal disease?)
eukaryotes (with a nucleus)
Viruses:
cells (eukaryotic / prokaryotic / no)
size (smallest / small / large / largest)
nucleic acid: DNA (and / or) RNA
ribosomes (80S / 70S / no)
mitochondria (yes / no)
cell wall (peptidoglycan / chitin / none)
motility (usually / sometimes / none)
reproduction by binary fission (yes / no)
no
smallest
or
no
no
none
none
no
Bacteria:
cells (eukaryotic / prokaryotic / no)
size (smallest / small / large / largest)
nucleic acid: DNA (and / or) RNA
ribosomes (80S / 70S / no)
mitochondria (yes / no)
cell wall (peptidoglycan / chitin / none)
motility (usually / sometimes / none)
reproduction by binary fission (yes / no)
prokaryotic
small
and
70S
no
peptidoglycan
sometimes
yes
Fungi:
cells (eukaryotic / prokaryotic / no)
size (smallest / small / large / largest)
nucleic acid: DNA (and / or) RNA
ribosomes (80S / 70S / no)
mitochondria (yes / no)
cell wall (peptidoglycan / chitin / none)
motility (usually / sometimes / none)
reproduction by binary fission (yes / no)
eukaryotic
large
and
80S
yes
chitin
none
yes
Protozoa/Helminths (Parasites):
cells (eukaryotic / prokaryotic / no)
size (smallest / small / large / largest)
nucleic acid: DNA (and / or) RNA
ribosomes (80S / 70S / no)
mitochondria (yes / no)
cell wall (peptidoglycan / chitin / none)
motility (usually / sometimes / none)
reproduction by binary fission (yes / no)
eukaryotic
largest
and
80S
yes
none
usually
yes
Viruses:
(obligate/facultative) (intracellular/extracellular) pathogens (they require the host cell for _)
Have DNA (and/or) RNA.
No independent _ production or _ synthesis
Usually show selectivity for infecting _
Not sensitive to _ (e.g. penicillins)
obligate intracellular
replication
or (not both)
energy
protein
particular types and/or species of host cells
antibacterial/antifungal antibiotics
Bacteria (prokaryotes):
DNA enclosed by a nuclear membrane (yes / no)
chromosome number (usually 1 / >1)
membrane-bound organelles, e.g., mitochondria (yes / no)
ribosomes (70S / 80S)
peptidoglycan in cell wall (yes, except _ / no)
sterols in plasma membrane (yes / no, except _)
no
usually 1
no
70S
yes, except Mycoplasma spp. & (probably) Chlamydiae spp.
no, except Mycoplasma spp., Helicobacter pylori & Borrelia burgodorferi
Eukaryotes:
DNA enclosed by a nuclear membrane (yes / no)
chromosome number (usually 1 / >1)
membrane-bound organelles, e.g., mitochondria (yes / no)
ribosomes (70S / 80S)
peptidoglycan in cell wall (yes, except _ / no)
sterols in plasma membrane (yes / no, except _)
yes
> 1
yes
80S
no
yes
Bacteria:
Bacteria lack _ and _
Bacteria usually have _ made of _ (exceptions: _ and _)
Bacteria have _ ribosomes
Bacteria (and eukaryotes) have RNA (and/or) DNA, make their own _ (except for
_ and _) and have independent _ synthesis
Most Bacteria lack _ in their plasma membrane (except _, _, and _)
Bacteria are usually about 1/5th to 1/10th the size of _ (need _ to visualize)
nuclei and internal organelles
cell walls
peptidoglycan
Mycoplasma and Chlamydiae
70S
and
energy (Rickettsiae and Chlamydiae)
protein
sterols (Mycoplasma spp., Helicobacter pylori and Borrelia burgodorferi)
eukaryotes
oil immersion lens
Bacteria:
morphology (3)
arrangements (3)
cocci
rods
spirochete
diplococci
cocci in chains
cocci in clusters
Bacterial Cell Components (3)
Cytoplasm
Cell envelope
External structures (if present)
Bacterial Cell Components:
Cytoplasm (3)
DNA, ribosomes, metabolic enzymes
site of some antibiotic action
outer membrane (if present)
Bacterial Cell Components: Cell envelope (3)
plasma membrane
cell wall (target of some antibiotic action)
outer membrane (if present)
Bacterial Cell Components: External structures (if present) (4)
common pili
capsule
sex pilus
flagella
Role of Bacterial Cell Components:
Cytoplasm:
DNA, ribosomes, metabolic enzymes: _ processes
site of some antibiotic action (e.g., _ inhibitors, antibiotics affecting _ or _)
plasmids: antibiotic _ and _
basic life
protein synthesis
DNA replication or RNA transcription
resistance and virulence
Role of Bacterial Cell Components:
Cell envelope:
plasma membrane: _ and _
cell wall (target of some antibiotic action): resists _
outer membrane (if present): _ (but contains _ and _)
permeability barrier and transport
osmotic lysis
permeability barrier
pumps and pores
Role of Bacterial Cell Components: External structures (if present):
common pili: _
capsule: _, can result in _ formation
sex pilus: _
flagella: _
attachment to tissue
antiphagocytic
biofilm
conjugation
motility
Bacterial Cell Wall Synthesis:
_ crosslinking is carried out by _ (also known as _).
Peptidoglycan
transpeptidases
penicillin binding proteins (PBPs)
The Gram Stain:
Procedures (4)
stain
mordant
decolorize
counterstain
The Gram Stain:
Gram+ and Gram- procedure colors
Stain
Mordant
Decolorize
Counterstain
Stain: purple, purple
Mordant: purple, purple
Decolorize: purple, clear
Counterstain: purple, red
Structures/components unique to gram+ bacteria (2)
Lipoteichoic acid
Teichoic acid
Examples of medically-important gram+ bacteria (3)
Streptococcus spp.
Staphylococcus spp.
Clostridium spp.
Structures/components unique to the gram-bacteria include the _
Some gram-s (e.g. the _) contain _
outer membrane
enterics lipopolysaccharide (LPS)
Structures/components unique to the Gram-negative bacteria:
LPS consists of three regions (3)
lipid A
core
O antigen
Structures/components unique to the Gram-negative bacteria:
LPS consists of three regions:
lipid A: has _ activity
a core: _
O antigen: important for _ and _, very variable _
endotoxic
conserved
bile and complement resistance
polysaccharide
Gram-negatives can be stereotyped for their antigens (3)
O
H
K
Gram-negative antigens:
O: _, _ portion of LPS
H: found on _
K: _ antigen
variable, outermost
flagella
capsular
Some (mostly _) Gram-negative bacteria have an LPS-like molecule in their outer membrane instead of true LPS.
This molecule, _, lacks the _ antigen but retains the _ and _ regions of LPS.
nonenteric
lipooligosaccharide (LOS)
O
core
lipid A
Being gram- vs. gram+
Advantage: _ from the _ (including some antibiotics)
Disadvantage: _ to make, hard to _ through _
Protection from the environment
expensive
secrete proteins through two membranes
Structures/components unique to the Gram-negative bacteria:
_: channels in outer membrane, allow molecules to _
Alterations can impact _
Porins
move across the outer membrane
antibiotic resistance
Some examples of Gram negative pathogens (4)
Shigella spp.
Salmonella spp.
Vibrio cholerae
E. coli
“Atypical” Myobacteria:
Stain: _
Cell envelope functions (2)
Cell envelope components (4)
Acid-fast
resistance to desiccation & phagocytosis
helps disease transmission
waxy layer
phenolic glycolipid
mycolic acids
peptidoglycan
Examples of medically-important Mycobacterium spp. (2)
Mycobacterium tuberculosis
Mycobacterium leprae
“Atypical” Spirochetes:
These bacteria can be visualized only by _
Examples (2)
dark-field microscopy
Borrelia burgdorferi
Treponema pallidum
“Atypical” Rickettsiae spp.:
Distinguishing features: (facultative/obligate) (intracellular/extracellular) bacteria that are _
Rickettsiae spp. generate some _ but probably need to get some from host cell
Can be transmitted by _
Have typical Gram(+/-) envelope, but too small to _
obligate intracellular
vector-borne
energy
fleas, ticks, lice, etc.
negative
Gram-stain
Medically important Rickettsiae spp. (2)
R. rickettsii: rocky mountain spotted fever
R. typhi: endemic typhi
“Atypical” Chlamydiae and Chlamydophila spp.:
These are (facultative/obligate) (intracellular/extracellular) bacteria with a complex life cycle (_ bodies and _ bodies)
_ parasites
Have (#) membranes like Gram-negatives, but no _
Too small to see by _ stains
obligate intracellular
reticulate
elementary
Energy
two
peptidoglycan
Gram
Examples of medically important spp. (3)
Chlamydiae trachomatis: blindness, nongonococcal urethritis, pneumoniae
Chlamydophila psittaci: psittacosis (a form of pneumonia)
Chlamydophila pneumoniae: pneumonia
Chylamydiae:
Can grow outside host cell (yes / yes, except / no / no, except)
Have independent protein synthesis (yes / no)
Generate metabolic energy (yes / no / sometimes)
Shown to have peptidoglycan-containing cell wall (yes / no / no except)
Susceptible to antibiotics (yes / no)
Reproduced by binary fission (yes / no)
Nucleic acids (DNA and / or RNA)
no
yes
no
no, except Chlamydiae have two membranes (like gram-negative bacteria) but have not been shown to have a peptidoglycan
yes
yes
and
Typical bacteria:
Can grow outside host cell (yes / yes, except / no / no, except)
Have independent protein synthesis (yes / no)
Generate metabolic energy (yes / no / sometimes)
Shown to have peptidoglycan-containing cell wall (yes / no / no except)
Susceptible to antibiotics (yes / no)
Reproduced by binary fission (yes / no)
Nucleic acids (DNA and / or RNA)
yes, except for a few obligate intracellular pathogens, e.g., Mycobacterium leprae
yes
yes
yes
yes
yes
and
Rickettsiae:
Can grow outside host cell (yes / yes, except / no / no, except)
Have independent protein synthesis (yes / no)
Generate metabolic energy (yes / no / sometimes)
Shown to have peptidoglycan-containing cell wall (yes / no / no except)
Susceptible to antibiotics (yes / no)
Reproduced by binary fission (yes / no)
Nucleic acids (DNA and / or RNA)
no, except for Rochalimaea quintana
yes
sometimes
yes
yes
yes
and
Mycoplasma:
Can grow outside host cell (yes / yes, except / no / no, except)
Have independent protein synthesis (yes / no)
Generate metabolic energy (yes / no / sometimes)
Shown to have peptidoglycan-containing cell wall (yes / no / no except)
Susceptible to antibiotics (yes / no)
Reproduced by binary fission (yes / no)
Nucleic acids (DNA and / or RNA)
yes
yes
yes
no
yes
yes
and
Virus:
Can grow outside host cell (yes / yes, except / no / no, except)
Have independent protein synthesis (yes / no)
Generate metabolic energy (yes / no / sometimes)
Shown to have peptidoglycan-containing cell wall (yes / no / no except)
Susceptible to antibiotics (yes / no)
Reproduced by binary fission (yes / no)
Nucleic acids (DNA and / or RNA)
no
no
no
no
no
no
or
“Atypical” Mycoplasma spp.:
Very (large/small), lack a _, and have _ in their
plasma membranes
Can be (slowly) grown on _ media
The absence of a cell wall affects _ sensitivity
The major pathogenic Mycoplasma spp. is _ (causes an atypical _)
small
cell wall
sterols
artificial
antibiotic
M. pneumoniae
pneumonia