CH2: Structure of Bacterial Cells Flashcards
3 bacterial groups by shape
cocci: round
bacilli: rods
spirochetes: spiral-shaped
pleomorphic
Bactria that are variable in shape (many-shaped)
The shape of a baterium is determined by its
rigid cell wall
Cocci in clusters
e.g., Staphylococcus
Cocci in chains
e.g., Streptococcus
cocci in pairs with pointed ends
e.g., Streptococcus pneumoniae
Cocci in pairs with kidney bean shape
e.g., Neisseria (two kidney beans kissing)
Bacilli with square ends
e.g., Bacillus
Bacilli with rounded ends
e.g., Selmonella
Bacilli club-shaped
e.g., Corynebacterium
Bacilli fusiform
e.g., Fusobaterium
Bacilli comma-shaped
e.g., Vibrio
Spirochetes, relaxed coil
e.g., Borrelia
Spirochetes, tightly coil
e.g., Treponema
diplococci
cocci occur in pairs
cocci occur in chains
streptococci
cocci occur in grapelike clusters
staphylococci
bacteria size range
0.2 to 5 micrometer
smallest bacteria
Mycoplasma
outermost component common to all bacteria, except Mycoplasma
cell wall (Mycoplasma species are bounded by a cell membrane, not a cell wall)
The bacterial cell wall is located external to the cytoplasmic membrane and is composed of
peptidoglycan
Comparison of cell walls of Gram-positive and Gram-negative bacteria
peptidoglycan
teichoic acids
Lipopolysaccharide (endotoxin)
peptidoglycan: G(+) thicker, multilayer; G(-) thinner, single layer
teichoic acids: only in G(+)
Lipopolysaccharide (endotoxin): only in G(-)
periplasmic space
space between outer membrane and inner cytoplasmic membrane in G(-)
bacteria; contains beta-lactamases
beta-lactamases
degrades penicillins and other beta-lactam drugs
