Lecture 5 Flashcards
(46 cards)
What are the 3 domains coming from the universal ancestor?
- eukaryota
- archaea
- bacteria
What does biocide mean?
It is a general term describing a chemical agent that inactivates microorganisms. (examples: antiseptics, disinfectants, or preservatives)
What does bacteriostatic mean?
A term referring to the property by which a biocide is able to inhibit bacterial multiplication. Multiplication resumes upon removal of the agent (reversible).
What does bactericidal mean?
A term referring to the property by which a biocide is able to kill bacteria. It is irreversible.
What does sterilization mean?
A physical or chemical process that completely destroys or removes all microbial life, including spores.
What are disinfectants?
Products or biocides used to kill microorganisms on inanimate objects or surfaces
What is an antiseptic?
A biocide or product that destroys or inhibits the growth of microorganisms in or on living tissue.
What is aseptic?
Characterized by the absence of pathogenic microbes.
What is preservation?
The presentation of multiplication of microorganisms in formulated products, including pharmaceuticals and foods.
What are antibiotics?
Naturally occurring or synthetic organic compounds which inhibit or destroy selective bacteria, generally at low concentrations.
What does septic mean?
Characterized by the presence of pathogenic microbes in living tissue
Where are bacterial capsules found?
Found outside the cell envelope
Most capsules are what?
Polysaccharides (hydrophilic and gel-like)
What do bacterial capsules protect against?
They protect against phagocytosis by the white cells (macrophages and PMNs)–this is important in virulence.
What is the chemical basis of several vaccines?
Bacterial capsules because they are important antigenic determinants.
What is the glycocalyx?
It is adhesive polysaccharides, polypeptides or both (biofilm). It is a planktonic form to colony with biofilm or a viscous gelatinous polymer that is external to the cell wall.
Where are flagella found?
In motile bacteria that can alter the direction of rotation as well as speed.
How long are flagella?
3 to 12 microns long (125 to 250 angstroms thick)
What types of flagella are there and what are they used for?
- can be at one or both ends (polar) or all around (peritichous)
- used for locomotion
What do flagellin protein make up?
H-antigens–they are highly changeable (phase variation) to evade immune attack
What are the 3 types of bacterial chemotaxis?
- directional movement (counterclockwise)
- tumbling motility (clockwise)
- aggressive, speedy movement (pathogenic role in mucus penetration and invasion)–counterclockwise
What are the 5 purposes of bacterial chemotaxis?
- Swim toward an attractant (mucosal epithelial cellular target)
- Avoid being swept away by mucus
- Flee from an attacker (WBC)
- Swim towards nutrients
- Invasion and Intracellular movement
What propels the flagellum?
PMF: proton motive force from membrane bound oxidative phosphorylation. It propels a motor that allows the flagellum to rotate.
What is oxidative phosphorylation?
Protons flow down concentration gradient turning ADP into ATP. The flow of protons across the bacterial cell membrane is due to the concentration gradient.
