Bacterial Structure 2&3. 5 Flashcards
pili and fimbriae are primarily? functions?
exterior protrusions
involved in attachment to tissue including salivary components
May also be involved in movement
involved in conjugation to other bacteria of same species
viruses that infect bacteria sometime use these as receptors
Longer protrusions are? shorter are?
longer= fimbriae shorter= pili
fimbriae main function?
attachment
pili main attachment?
conjugation
pili and fimbriae composed of?
protein subunit called pilin
example of a human pathogen that has fimbrae that are virulence factors
Bordetella pertussis
Prokaryotes may contain one of several types of cell surface layers composed of?
Capsule
S-layer
slime layer
capsules and slime layers are involved in?
attachment and prevent phagocytosis
*Capsule prevents phagocytosis by macrophages or neutrophils and protects cell from its environment
Capsule
Rigid polysaccharide layers firmly attached to cell
S-layer
- two-dimensional arrays of proteins
* a selective sieve, allowing passage of low-molecular-weight substances while excluding large molecules
slime layer
Diffuse, amorphous, less compact polysaccharide matrix
What bacteria has a Polysaccharides caspsule?
-Streptococcus pneumoniae
What bacteria has a hyaluronic acid caspsule?
-Streptococcus pyogenes
What bacteria has a poly-D-glutamic acid caspsule?
-Polypeptides-Bacillus anthracis
What bacteria has a dextran and levan-polysaccharides caspsule?
-Streptococcus mutans
another name for storage granules?
inclusions
Many bacteria have Storage granules
(inclusions) that are composed of? produced under conditions of? Examples?
- composed of high molecular weight polymers
- produced under conditions of unbalanced growth
- Ex: Volutin
What does does Volutin stain? What is it?
a metachromatic granule storage granule
* toluidine blue causes volutin to stain
reddish violet
what is Polybetahydroxybutyric acid?
polymer of C4 fatty acid
*Volutin stoarge granules are full of this
Glycogen Storage granules are polymers of?
glucose with alpha1-4/alpha1-6 bonds
Glycogen Storage granules stain what color?
stains red with addition of potassium iodide
when bacteria are carbohydrate deficient then glycogen is degraded by
glycogen phosphorylase to allow glucose to enter glycolysis
HOW can Streptococcus mutans cause caries even during the overnight when sucrose is not eaten?
via Glycogen Storage granules
*when bacteria are carbohydrate deficient then glycogen is degraded by glycogen phosphorylase to allow glucose to enter glycolysis
The endospore is a highly resistant _____ bacterial cell produced by?
differentiated bacterial cell produced
by certain gram-positive Bacteria
how do bacteria survive extreme environments?
spore formation
**Endospores can germinate a live cell even after many decades, centuries, or millennia
spores are resistant to?
heat, drying, radiation, chemicals
what color do spores stain?
they don’t. difficult to stain, clear
Bacillus species are aerobic or anaerobic?
aerobic
Clostridium species aerobic or anaerobic?
anaerobic
endospores are formed by how many genes? takes how long? formed because? Formed in certain genus and species?
- 500 genes
- 10 hours
- lack of nutrition, bad environment
- **Formed in certain genus and species such as Bacillus and Clostridium species
spores are killed in autoclave at?
120oC for 20 min under 15 lb pressure
what are the 4 layers of endospore?
Exosporium
Coat
Cortex
Core wall
Exosporium
outermost layer-lipoprotein membrane
Coat
very stable keratinlike protein
Cortex
thickest layer composed of
peptidoglycan with fewer peptide
crosslinks
Core wall
peptidoglycan
Small acid-soluble proteins of endospore
protect?
DNA of endospore from ultraviolet
radiation, desiccation, and dry heat and also serve as a carbon and energy source during germination
dipicolinic acid
is unique to spores
*Spores contains a high amount of divalent calcium bound up by dipicolinic
what is unique about spore pH?
is one unit lower than usual
