What is chemiosmosis? (in context of metabolism)
The process of H+ moving across a semipermeable membrane down an electrochemical gradient in order to produce ATP
What is asepsis?
Absence of significant contamination
What is the disk diffusion method used for?
Screening of antimicrobial agents
What is enrichment media?
It is a media that is used to grow a lot of microbes before further culturing (usually a 1st media)
Neisseria meningitidis, E.coli, Bacteroides, Pseudomonas, lactobacilli
What is the purpose of the krebs cycle?
To thoroughly oxidize pyruvate, this cycle provides a lot of electron carriers that will donate electrons to the ETC (NADH, FADH2)
What is non-ionizing radiation used for? (UV-B)
Treatment of spaces
Aldehydes are commonly used to clean what kind of material?
Commonly used for disinfection of sensitive instruments that cannot be put in an autoclave
What is the chemical requirement for bacterial growth?
What is MBC and MIC?
Minimum bacterial cidal concentration
Minimum inhibitory concentration
Explain the differences between aerobic respiration, anaerobic respiration, and fermentation.
Aerobic: Cellular respiration in the presence of oxygen. Glycolysis - krebs cycle - ETC - higher ATP yield
Anaerobic respiration: Respiration without the presence of oxygen, the final electron acceptor is an inorganic molecule
Fermentation: Done in without oxygen, NET 2 ATP yield, makes some sort of end product out of pyruvate in order to recycle the electron carrier NAD
What is an autoclave/what are its features?
An autoclave is a sterilization device that is considered the "gold standard" for sterilization. This is because it has to ability to kill endospores. The autoclave works by using steam under high pressure (moist heat - denatures proteins). It is used with heat-stable materials.
What do phenol-derived disinfectants do to limit microbial growth? (what is their drug target)
Disrupts plasma membranes and denatures proteins.
Name the 6 conditions that influence bacterial metabolism.
temperature, pH, tonicity, oxygen conditions, substrate concentration, enzyme inhibition
What is chemically-defined and complex media?
Chemically-defined media: The exact chemical composition is known (specifically weigh everything out) Used for assays with specialized bacteria
Complex media: The exact chemical composition is not known. Made from extracts, digests of yeast and meat, etc.
What toxic substances are produced from aerobic respiration? How do bacteria detoxify these compounds?
Toxic: O2- and H2O2, enzymes detoxify these compounds.
Ionizing radiation; useful on heat-labile materials
What type of materials are used with dry heat? how does dry heat kill microbes?
heat-stable, oxidation.
Name the 8 factors that can influence the "growth" of microorganisms
2. Enviornmental conditions
3. Nutrients
4. Temperature
5. pH
6. oxygen
7. tonicity
8. competition with other microbes
Name 3 features of an enzyme
3D protein, shape is critical to function, substrate specific, biological catalyst, catalyze one specific reaction, cells' genetics determine what it can hydrolyze/synthesize. In cell or secreted
Explain the general process of the electron transport chain in aerobic respiration
Electrons are donated by NADH and FADH2 to the electron transport chain
As these electrons are passed from protein to protein, H+ pass through the membrane via the transmembrane proteins into the extracellular space
This creates a gradient and concentration of protons (inside of the cell more negative than the outside of the cell)
Electrons eventually come to the last protein and get passed off to the final electron acceptor, oxygen, and forms water
These H+ move down their concentration gradient back into the cell via ATP synthase
The movement of H+ through ATP synthase facilitates the the formation of ADP + P into ATP
What are the three heavy metals used for chemical control of microbial growth? How do these kill bacteria?
Kill by disrupting plasma membranes and denaturing proteins
Name the features of "filtration" to control microbial growth
neither cidal nor static, used with pyrogens.
Describe the lag phase, log phase, and stationary phase of the microbial growth curve
Lag: The bacteria are sensing the enviornement and expressing genes; not much is happening
Log phase: Exponential growth, most metabolically active at this point, and most antibiotic sensitive
Stationary phase: Bacteria have either depleted the media or produced toxic end products that have built up; they are dying at the same rate as they are dividing
When can your normal flora cause infections?
When they are out of place, or they are out of balance
- microbes in your normal flora keep each other in check, if this balance is disrupted, it can cause an infection