UMMC Micro test 2 2nd
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What are the major inorganic ions required for bacterial growth?
What are the trace elements required for bacterial growth?
- Molybdenum (Mo)
What are psychrophiles?
- Bacteria with a temperature range of -15-20° C
- Optimum growth at 10-15° C
What are mesophiles?
- Bacteria with a temperature range of 20-40°C
- Optimum growth at 30-40°C
What are thermophiles?
- Bacteria with a temperature range of 45-122°C
- Optimum growth at 50-80°C
Explain oxidation and reduction in terms of NAD
- OIL RIG – oxidation is loss reduction is gain
List the classification for each tube
- Aerotolerant = 1
- Obligate anaerobe = 2
- Facultative anaerobe = 3
- Microaerophile = 4
- Obligate aerobe = 5
What causes dental carries?
- Lactic acid produced during fermentation by Streptococcus mutans
- Rare example of normal bacterial flora causing disease
What causes gas gangrene?
Clostridia (eg Clostridium Perfringens) generate H2 gas during fermentation that can be felt under the skin of a patient with gas gangrene
Which side of the cell are Hydrogen ions concentrated on during bacterial aerobic respiration?
The outside of the cell
How does the ATP motor work? Be sure to include a unit, c-ring, and gamma unit
- Protons from outside the cell enter a unit and bind to c-ring subunit
- C ring and gamma unit turns and projects proton internally
- Rotation forces gamma unit to center of the hexamer which allows the energy of rotation to be trapped in phosphate bonds producing ATP
How many hydrogens are required to drive a bacterial flagella motor one revolution?
What type of flagellar motor does Vibrio cholerae use?
They use a sodium driven flagella outside a host, but during an infection they swap to a hydrogen driven flagella
What are the types of bacteria classified according to oxygen consumption?
- Obligate anaerobe
- Facultative anaerobe
- Obligate Aerobe
What are the catalase positive organisms?
- • Staphylococci (important not confuse it with streptococci)
- • Pseudomonas aeroginosa
- • Aspergillus fumigatus
- • Candida
- • Enterobacteriaceae (specially Klebsiella and Serratia both of which can cause pneumonia and UTI)
Which group(s) of bacteria lack enzymes such as catalase for detoxifying oxygen radicals?
- Obligate anaerobes
- This is why they cannot tolerate an oxygen-rich environment, because the free radicals cannot be dealt with
Do streptococci have catalase? What classification are they based on O2 consumption?
They are aerotolerant and they lack catalase
Do staphylococci have catalase? What classification are they based on O2 consumption?
They are facultative anaerobes and they have catalase as well as superoxide dismutase and peroxidase
How do bacteria divide?
- FtsZ is a tubulin-like protein that assembles as a ring of filaments (the Z-ring) at mid-cell
- MinCDE proteins ensure that the Z-ring forms at mid-cell.
- MinCD prevents FtsZ from forming at the poles, and MinE prevents MinCD from forming at mid-cell
- Z-ring constricts and forms a septum and then divides the cell
- *Mutations in Min proteins allow Z-ring to form at an inappropriate site
How is Proline used in bacteria?
organic osmolyte used in maintaining osmotic balance and salt tolerance in bacteria
What are the three strategies bacteria use to acquire iron?
- Siderophore systems: iron binding complexes secreted by bacteria which bind iron and are then taken up by the bacteria
- Transferrin and Lactoferrin: some bacteria can make receptors for these directly
- Heme acquisition: surface receptors that can strip Heme, once internalized iron is released also some release hemophores that act like siderophores but target heme instead of just iron
What three components are required to transport substances to the exterior of a gram negative cell?
ABC transporter, membrane fusion protein, Outer Membrane (OM) factor
What are the type III secretion systems used for?
- They are similar in structure to bacterial flagella/ATPase
- Needle-like and can puncture host cells and inject proteins
What is planktonic growth?
Life as a free living cell, floating or swimming in a liquid
What is Biofilm growth?
Life in a community, attached to a surface, encased in a matrix
What are the three staged of biofilm growth?
- Matrix development
- Dispersion (seeding other biofilms, can lead to chronic or secondary infections)
Biofilms commonly infect prosthetic joints, what are the two main organisms responsible for more than 90% of prosthetic joint infection?
Staphylococcus aureus and Staphylococcus epidermidis
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