Eating Habits - third set Flashcards
molecular patterns are expressed on..
pathogens and nonpathogens
plasma membrane (gram -) where and what it’s made of
is thin structure lies inside the cell wall, encloses cytoplasm defines the external boundary of cell. made of phospholipids, proteins, and glycoproteins.
Plasma membrane has dynamic role
acts as selective barrier; monitors flow in both direction. ATP/energy demands constant, appropriate internal environment
membrane structure…
best explained by the Fluid Mosaic model. Membrane resembles a sea of lipids with an mosaic of embedded proteins and attached sugar molecules
Lipids (physio)
arranged as bilayer, composed mainly of phospholipids
proteins
are in motion laterally: grouped into 2 classes, Integral and Peripheral proteins
Cholera ToxR : Transmembrane protein ( Biosensor) (parasite swimming)
Allows for rapid sensing and activation of pathogenic functions ToxR
is able to detect acidity and high temps ( signs of host digestive system)
NH2 part reaches cytoplasm
- NH2 terminal domain binds to DNA sequence as a transcriptional activator in turn, activates cholera toxin gene expression as well as other virulence factors
transport system (small cars)
mechanism that facilitates small molecules to enter cell across the normally impermeable membrane
role of transport system
A. To bring in nutrients B. Expel waste products and substances harmful to the cell (efflux) C. Secretion
i. secretion of selective protein molecules which are structural components (like porins proteins of gram negative cells - made in cells) ii. toxins which are virulence factors iii. secretion of enzymes (ex. exoenzymes like amylase) - breaks down large substances for absorption
Transport process is..(PCCT)
PCCT
the functional outcome of activity of channel proteins / transport proteins / carrier protein / permeases
bacterial cell anatomy
AACE
cell envelope, appendages, cytoplasm, accessory structures
External structures
includes cell envelope and appendages
appendages
PEFF
flagella, fimbriae, pili and endoflagella
Flagella (spins..)
spins, forward, uses energy
2/3 energy used for flagella . long, semi rigid and filamentous appendage, aids in motility acts as a spinning motor, propels cell in forward direction flagella motility involves expenditure of cellular energy.
Flagella has 3 basic parts
Filament, hook and basal body
flagella arrangement - names (lamp)
monotrichous, peritrichous, amphitrichous, and lophotrichous
Monotrichous
single polar flagella, Ex: Pseudomonas aeroginosa
Peritrichous
flagella distributed over entire surface, Ex: E. coli
Amphitrichous (spiral voltans)
tuft of flagella at each end of cell Ex: Spirillum volutans
Lophotrichous
two or more flagella at one pole of cell, Ex: Helicobacter pylorii, helps bacteria to cross the mucosal coating of the intestinal epithelium
Favorable stimulus
positive taxis
Unfavorable stimulus (NY)
negative taxis
Attractant and Repellent (runner)
Attractant: more runs of longer duration and less tumbles Repellent: more tumbles
Pili (pill)
F pili - shorter than flagella, 1- 10 per cell, always evolves
Pili (sing pilus) - also called sex pili or F pili or conjugation pili; shorter than flagella - usually 1- 10 sex pili per cells - aids in joining cells of opposite mating types during conjugation process - is one of the methods of genetic exchange of genetic material between bacterial cells. no sexual reproduction. always evolves due to exchange of genetic material
Fimbriae: (variation of pili) (black bug crawling up pole)
- fimbriae number varies (few to thousands); distributed throughout or have polar concentration- aids in attachment to substrate (ex. epithelial surface) as well as to one another - harbors adhesin (special molecule), either at the tip or all along it’s length
Both pili and fimbriae have pilin proteins. pilin proteins acts as PAMP.
Endoflagella
it is an appendage - present in Spirochetes, Ex: treponema paladium and borrelia berdoffori there is an outer sheath (membrane), below which are fibrils (axial filaments) sheath is anchored at one end and spirals around cells - uses cork screw motion to drill into viscous tissues of their host
chromosomes (strand)
- it’s single, circular, double stranded DNA molecule (supercoiled) with associated
proteins - are nonhistone proteins; exception vibrio cholera - anchored to plasma membrane; confined in nucleoid area
plasmids
- small, extrachromosomal DNA molecules- self replicating units - when a cell divides, plasmid DNA replicates and is distributed to daughter cells. are not required for metabolism / survival under normal condition. presence provides selective advantage to the bacteria like antibiotic resistance.
plasmid functions
plasmid carry genes for activities such as,- antibiotic resistance - toxins production -plasmid DNA may code for toxin
plasmid types
BRVF
fertility, resistance, virulent, Bacteriocin plasmid
Fertility plasmid
codes for the sex pili ( F pili) - involved in conjugation process
resistance plasmid
carry resistance genes for antimicrobial agents (antibiotics and heavy metals) heavy metals stop bacterial growth - as resistance genes - are self transmissible plasmids - aka plasmid DNA codes for sex pili
Bacteriocin plasmid
carry genes for the bacteriocin. bacteriocin toxin kills other competing bacteria cells that lacks bacteriocin plasmid, carried by intestinal bacterias.
virulent plasmid
carry genetic information for virulence structures, enzymes or toxins. - 3 components of toxin - all 3 needed for efficacy
plasmid - self transmissibility (3 types)
has genes that codes for sex pili, origin of transfer, and mobilization of the genes.
copy number
number of copies of each kind of plasmid per cell
host range
ability of plasmid to multiply in cell type
ribosomes (aka ribonucleoprotein particles) (translator w/ target)
associated with bacterial translation (means protein synthesis) - are smaller, less dense than eukaryotic ribosomes (70 S vs 80S) made of 2 subunits; preferred target site of some antibiotics action. many antibiotics target small units, can tell between our subunits. some target large, erythromycin. subunit is made of RNA and proteins
Metachromatic granules (aka volutin granules) (plants)
PPANE
when bacteria are growing in phosphorus rich environment. meta means change, choromatic means color- represents polyphosphate granules- can be degraded and used as iP (inorganic phosphorus) source for ATP synthesis, nucleic acid, enzyme reaction, phosphoproteins, phospholipids- stains red with some blue dyes (methylene blue- characteristic feature of Corynebacterium diptheriae
Polysaccharides granules
includes starch and glycogen - they are storage depot for carbon and energy source- clinically useful for Chlamydia sps identification
Lipid inclusion (poly β- hydroxy butyric acid) (poly)
represented by inclusions of poly β- hydroxy butyric acid; surrounded by monolayer membrane - (hydrophobic lipid)- like polysaccharide, they are carbon and energy storage polymer- observed in Mycobacterium sps - used for mycolic acid synthesis
integral proteins
extend into or through the lipid bilayer - typically are trans membrane proteins / permeases. (channel or transport protein) ex. cholera membrane trans protein acts as a biosensor.
Peripheral proteins
attached to inner or outer surface of membrane- functions as enzymes, scaffold, receptors etc. Scaffold helps maintain structure