Bacteria structure Flashcards
list 2 symbiotic bacteria of humans
streptococcus pneumonia
escherichia coli
list two nutrients that the human body can’t process that bacteria help to metabolize/produce
Vit B12
nitrogen
Peptidoglycan present in bacteria cell wall is also called
murein
what kind of sugars are present in peptidoglycan
dissacharides
the main function of peptidoglycan is to
maintain cell shape
cell wall maintains osmotic pressure in what kind of environment
in hypotonic environment
____determines the reactivity to gram stain
The cell wall
Techoic acid is an antigenic polysaccharide present in gram + cell membrane
T or F
F
cell wall
gram negative bacteria which their peptidoglycan have been digested away(hence their cell wall is lost) are called
Protoplasts
nb: protoplast require an isotonic environment for survival else they die
gram positive posses a thicker peptidoglycan layer in their cell wall than gram negative
T or F
T
The outercell membrane of gram negative bacteria repels hydrophilic substance
T or F
F
it excludes all hydrophobic substances
this property protects the bacteria from bile salts and gut toxins
poring are present on __A__ and their function is __B__
A - outer cell membrane of gram negative
B - allows low molecular weight hydrophilic molecules to pass through
the outer membrane of gram negative bacteria provides antibiotic resistance by slowing down penetration of LARGE antibiotics
T or F
T
digestive enzymes e.g(B-lactamases) and other transport proteins are present in the periplasmic space
T or F
T
periplasmic space is present in both gram + and gram -
T or F
F
only gram negative as they have two membranes i.e periplasmic space means intermembrane space
The lipopolysaccharide present in gram - bacteria cell wall consists of
Lipid A
Polysaccharide 0
what is the function of these molecules
a.Polysaccharide O
b.Lipid A
a. serves as an antigen used for serotyping
b.also called endotoxin, it is pyrogenic and can trigger septic shock
penicillin
lysozyme
phagocytosis
LPS can protect the bacterium from all these
T or F
T
what kind of antigen are present on the flagella
H antigen
this H antigen are targeted in antibody response to bacteria
list the 4 types of flagella
polar/monotrichous - one flagella at one of the pole of the cell
lophotrichous - a tuft of flagella at one pole of the cell
amphitrichous - one or more flagella at both poles of the cell
peritrichous - many flagella covering the whole cell
Proteus spp. show what kind of growth on solid media
swarming growth
capsules of many bacteria can aggregate to form a
biofilm
which may protect them from toxins and antibiotics
what is the first step in bacteria colonization and it is facilitated by what cell structure
adherence
it is facilitated by the bacterium capsule
Presence of capsule is a virulent factor
T or F
T
protects bacteria from phagocytosis by immune cells
