Module 4 Flashcards
what term is used for the cell membrane of Gram + bacteria
cell wall
what term is used for the cell membrane of Gram - bacteria
envelope
what is the only aspect of bacterial cells more complex than in eukaryotic cells
envelope / cell wall / cell membrane
what is the function of the cell wall
maintain size and shape & provide strength
important in resisting changes in osmolarity of the external environment
what acts as a selective permeability barrier
cytoplasmic membrane
what does the bacterial cell membrane contain
- transport machinery
- secretion apparatus
- environmental sensors
what machinery is associated with the inner or cytoplasmic face of the cell wall
electron transport
what is used for motility & is anchored in the cell membrane
flagella
what is used for attachment and is anchored in the cell membrane
pili (fimbriae)
what are the components of the cell wall peptidoglycans
glycan, tetrapeptide side chains, peptide crosslinks
what is the major target of many anti-bacterial agents
cell wall peptidoglycan structure
Gram + bacteria have __, but NOT ___
teichoic acid, LPS
what kind of bacteria has a thick peptidoglycan layer
Gram +
what kind of bacteria has a thin peptidoglycan layer
Gram -
In what kind of bacteria is a thick peptidoglycan, a heavily cross-linked structure, and a rigid cell wall a component of
Gram +
what is at the outermost surface of the Gram + cell membrane
+ / - polysaccharide capsules
____ have Gram + cell walls, but stain ‘acid fast’ because of additional long-chain fatty acids (MYCOLIC ACIDS) on exterior
mycobacteria
what are the layers from outer to inner of the cell wall of mycobacteria
- capsule
- mycolic acids
- glycolipids
- arabinogalactan
- peptidoglycan
- lipid bilayer
what kind of bacteria has a more complex cell wall
gram -
What kind of bacteria has LPS
Gram -
what are the 2 parts of Gram - bacteria
- highly variable polysaccharide for strain typing = O-antigen
- lipid A component = endotoxin
*****bioactive - inflammatory properties (virulence factor)
what does the inner cytoplasmic membrane of Gram - bacteria have
normal phospholipid bilayer with INTEGRAL PROTEINS
what does the outer membrane of Gram - bacteria have
proteins & lipopolysaccharide (LPS) layer at surface
what is the space between membrane layers called
periplasm
what does the periplasm of Gram - bacteria contain
protein & lipoprotein & lower amounts of peptidoglycan
T/F some Gram - bacteria have a polysaccharide capsule at their surface
true
what is the purpose and function of the carbohydrate capsule on Gram + or - bacteria
- adhesion to surfaces
- contribution in forming colonies & biofilm
- increased environmental resistance
- evasion of immune system
- reduced phagocytosis
- physically shield protein antigens
what is the capsule considered in the H,O,K typing of Gram - bacteria
K
what does the H of H,O,K stand for
flagella
what does the O of H,O,K stand for
O-antigen
what does the K of H,O,K stand for
capsule
how are polysaccharide capsules visualized
India ink negative staining
which organisms often have flagella
ALL motile Gram + & - bacteria plus eukaryotic protozoans
which organisms often have fimbria/pilli
many Gram -
what does monotrichous refer to
single polar flagellum
what does peritrichous refer to
flagella over entire surface
what does lophotrichous refer to
cluster of flagella
what is flagella made of
polymerized flagellin
what are Gram - bacteria with a very unique flagella in the periplasmic space
spirochetes
ex: Treptonema spp.
what differentiates pili/fimbriae from flagella
thinner & much more per cell
what is a major virulence factor of pathogenic escherichias like E. coli that allows colonization of urinary tract epithelium
pili/fimbriae
what is the major function of pili/fimbriae
attachment to surfaces and cells and may also be involved in binding to other bacteria
what is the major components of plant and fungi cell walls
100% carbohydrates - like chitin
fungi are simple eukaryotes that possess a cell wall that lacks _
peptidoglycan
T/F bacteria in nature are often growing exponentially
false - true exponential growth is unsustainable and only seen routinely briefly in lab cultures
where does most of the material go when you are composting garbage
a - into the air, as carbon dioxide
b - it becomes a liquid and is absorbed of leaks out of containers
c - it is consumed by bacteria, which then migrate out of the area
d - we really don’t know
a - into the air, as carbon dioxide
yes, unless anaerobic, most of your compost waste goes into the air as CO2 though the action of soil bacteria using the nutrients for energy there in aerobic respiration
which of these is not an intracellular bacteria
a - streptococcus mutans
b - chlamydia
c - rickettsiae
d - mycoplasma
a - streptococcus mutans
which phsyiological process provides bacteria more energy as ATP then fermentation
a - aerobic respiration
b - anaerobic respiration
c - a & b
d - none of these do
c - a & b
what is the distinction in how the bacterial terms “cell wall” and “envelope” are commonly used?
a - wall for Gram +, envelope for Gram -
b - envelope refers only to the peptidoglycan layer
c - both refer to the entire outer surface of bacteria
d - cell wall refers to plant cell walls
a - wall for Gram +, envelope for Gram -
why are Gram positive bacteria typically more sensitive to widely used antibiotics like beta lactams?
a - the peptidoglycan target is on the outside of the bacteria
b - Gram positives have fewer DNA exchange mechanisms
c - a thicker cell wall gives them more mechanical strength
d - none of these, they are not
a - the peptidoglycan target is on the outside of the bacteria
what is the most significant function of a capsule for a pathogenic bacteria
a - they can block phagocytosis by immune cells
b - they increase uptake of nutrients by bacterial surface proteins
c - they allow bacteria to more easily move across epithelial surfaces
d - they are easily recognized by the innate immune system
a - they can block phagocytosis by immune cells
Which of these features of bacterial walls and envelopes are specific to Gram negative bacteria? Mark all correct answers this time, not just one.
a - teichoic acids
b - capsules
c - LPS –> lipopolysaccharide
d - flagella
e - fimbriae
c - LPS –> lipopolysaccharide
&
e - fimbriae
