Bacterial Physiology Flashcards
What is chemotaxis?
Movement of cell toward attractants and away from repellants; Direction of movement controlled by the direction of rotation of the flagellum. A counterclockwise turn makes the cell run. Clockwise turn makes the cell tumble.
How does bacteria vary surface antigen expression in flagella?
Phase variation allows it to turn on/off a flagella. Antigenic variation allows it to express different antigenic types. These events are not exclusive events.
What are pili?
Hair like protein projections on the bacterial cell surface. Allow attachment of bacteria to host cells; Type 1 will bind to mannose residues on host cell surfaces. Can undergo Phase/antigenic variation. Also inhibits phagocytosis.
What is a sex pili?
Involved in exchange of genetic material in some species.
What are endospores?
Produced under nutrient limitation or other stress. Extremely resistant to heat and drying.
What is sporulation?
Formation of spore from vegetative cell
What is germination?
Outgrowth of new vegetative cell from spore.
What are the energy sources for bacteria?
Light, oxidation of inorganic or organic compounds.
What are the nitrogen sources that bacteria use?
Inorganic: Ammonia, nitrates, nitrites, and nitrogen
Organic : Proteins, free amino acids
What role does iron play?
Essential for all bacteria. Needed for many enzymes. Steals iron from ferritin, transferritin, lactoferrin, hemoglobin, haptoglobin. The ability of a bacterium to compete successfully for host iron is a major virulence factor.
What element do few bacteria use instead of iron?
Manganese
What is a fastidious organism?
Organism that requires growth factors
What are the conditions for growth?
Most pathogens are mesophiles and prefer neutral to slightly alkaline ph.
What is an obligate aerobe?
Requires oxygen and can’t ferment; Possess catalase and SOD
What is an obligate anaerobe?
Grows only in the abscence of oxygen; Gets energy by fermentation. Do not usually possess catalase of SOD
