Exam 1 9/11 Nguyen Micro Flashcards
All known life on earth is:
carbon-based
Autotrophs
self feeders; making of own food by reducing CO2
Heterotrophs
cannot make their own food from CO2; must obtain food from outside sources (eating something else)
Photoautotrophs
Use light and CO2 to make food
Examples of photoautotrophs
Photosynthetic bacteria (green and purple sulfur), cyanobacteria, algae
Chemoautotrophs
Use chemicals (inorganic compounds) as reducing agents and CO2 to make food
What inorganic compounds can chemoautotrophs use to make food?
Hydrogen sulfide, sulfur, ammonium, ferrous ion
True or false: chemoautotrophs require light to make food
False
All human pathogens are:
heterotrophs
Chemoheterotrophs another name
Organoheterotrophs
Chemoheterotrophs cannot use ____ to make organic compounds; they must use ______
CO2; ready-made carbon (eating other organisms)
Photoheterotrophs
Use light and ready-made carbon to make organic molecules
Chemoheterotrophs
Use chemicals and ready made carbon to make organic molecules
Examples of photoheterotrophs
Purple and green nonsulfur bacteria
Examples of chemoheterotrophs
most bacteria, all protozoans, all fungi, all animals
What organism is limited by available O2?
obligate aerobes; tend to settle at top of test tube with lots of oxygen around
What bacteria are not limited by available O2?
Obligate anaerobes; tend to settle at bottom of test tube with no oxygen around
Which bacteria grows in presence or absence of O2?
Facultative anaerobes; dispersed throughout test tube, but more towards the top
Microaerophile
Low O2
True or false: all oral bacteria are towards the surface of the gums so they can be brushed away
False - some are anaerobes so they are found in pockets away from where you brush
When there is inflammation in a periodontal pocket, it is difficult for ____ to get in
saliva
Which anaerobic bacteria is associated with periodontal pockets?
Fusobacterium nucleatum
F. nucleatum tolerates up to ___% oxygen
6%
Mesophiles are found between what temperatures?
25-40 celcius
Most medically important class of bacteria
Mesophiles
Neutral pH
6.5-7.0
Acidophiles
Like acidic environment or can make acid; tolerate as low as 1.0
Halophiles
High osmolarity; found in brine or pickle, very salty environments
Important inorganic ion, often limited in supply
Iron
Bacterial iron sequestration protein
Siderophores
Human iron ions binding and transport proteins
Lactoferrin
Where is lactoferrin found?
saliva, tears, bile, pancreas, breast milk
Lactoferrin is considered an _______
Antimicrobial (if we are taking the iron, bacteria can’t use it)
How does siderophore sequester iron?
Secreted from bacteria, binds on to iron, then docks back onto the bacterial cell via receptor site
Major essential elements
CHONPS, K, Mg, Ca, Fe, Na, Cl
Minor essential elements
Zn, Mn, Mo, Se, Co, Cu, Ni, W
What enzyme do bacteria secrete to break down sucrose?
Sucrase
What enzyme do bacteria secrete to break down lactose?
Lactase
True or false: bacterial enzymes can remove glucose monomers from starch and glycogen
True
What carbohydrates serve as carbon sources for bacteria?
Sucrose, lactose, starch and glycogen
Main method of nutrient transport for bacteria
Active transport (ATP/proton pumps, permeases)
Active transport requires _____
energy (against conc gradient)
Growth phases of bacteria
- Lag
- Log
- Stationary
- Death/decline
Lag phase
adaptation; getting ready to grow, feeling out the environment, figuring out what genes to turn on
Log phase
rapid cell division when excess nutrients are available
During which growth phase would penicillin be most effective?
Log phase (since new cell walls are being built)
Stationary phase
Balance on nutrients/toxins
Death/decline
nutrient deficit, toxin buildup