Which of the following is NOT an environmental parameter that limits bacterial growth?
Temperature
pH
Metabolism
Osmotic pressure
None of the above
How is a psychrophile adapted to deal with extreme temperatures?
Increased number of saturated fatty acids
Short acetyl chains on fatty acids
Increased G-C content
Produces anti-freeze proteins
All of the above
Which of the following is true of cryoprotectants?
Bind to small ice crystals and prevent cell lysis
Insert into the plasma membrane to make it more fluid
A good example is Trehalose and exopolysaccharides
All of the answers
What would you expect an Alkaliphile to use to drive cell processes?
Protons
Potassium ions
Sodium ions
Calcium Chloride
What is a thermosome?
An bacterium that thrives in hot temperatures
A thermostable protein
A chaperonin protein complex
A glycerol tetraether
Which of the following is not mechanism by which halotolerant and halophilic bacteria respond to osmotic stress?
Release solutes through mechanosensitive channels
Stabilisation of S-layer glycoproteins with sodium ions
Production of compatible solutes inside the cell
Modification of mitochondrial metabolism
Which of the following is needed to catalyse the whole of this reaction?
Peroxidase
Superoxidase dismutase + catalase
catalase
Superoxidase dismutase + superoxidase reductase
Which of the following categories of bacteria contain catalase + SOD ?
Facultative aerobes
Obligate aerobes
Obligate anaerobes
Aerotolerant aerobes
Microaerophiles
Which of the following is an indirect measurement of bacterial growth?
Flow cytometry
Viable counting
Petroff-Hauser cell counting
Optical density
Select the correct order in a bacterial growth curve:
Log phase --> stationary phase --> lag phase --> death phase
Log phase --> lag phase --> death phase -->stationary phase
lag phase --> log phase --> death phase -->stationary phase
lag phase --> log phase -->stationary phase -->death phase
Which of the following is the correct definition for the thermal death point?
Minimal temperature at which all organisms are killed in 10 min in a particular liquid
Minimal temperature at which all organisms are killed in 1 hour in a particular liquid
Minimum time taken to kill all organisms at particular temperature in a given liquid
Minimal temperature at which all organisms are killed in 10 min in water
Which temperature does the dry heat (oven) method of steralisation occur at?
121 degrees celcius
150 degrees celcius
70 degrees celcius
100 degrees celcius
Which of the following ways does non-ionising radiation cause damage to the cell?
By breaking the DNA into fragments
By creating reactive oxygen species
By lysing the cell membranes
By mutating the DNA
Which of the following states would filtration be an appropriate method of sterilisation?
Gas
Liquid
Solid
Which of the following shows a bactericidal treatment? (note: top line shows cell count and bottom line shows viable cell count, x axis= Log number of cells y axis = Time)
Which of the following kills microorganisms but not necessarily endospores?
Disinfectants
Sterilants
Antiseptics
Which of the following can be applied to living tissue?
Germicides
Which of the following is a disc diffusion technique that allows the effective concentration to be seen?
E-test
Minimum inhibitory concentration
Minimum bactericidal concentration
What is the minimum bactericidal concentration?
The lowest concentration of a drug killing >99.9% of a test organism after overnight incubation.
The lowest concentration of a drug inhibiting the visible growth of a test organism after overnight incubation.
The lowest concentration of a drug killing >99.9% of a test organism after 48 hours of incubation.
The highest concentration of a drug killing >99.9% of a test organism after 48 hours of incubation.
Which of the following does not cause cell death by interacting with proteins?
Phenolic compounds
Alcohols
Aldehydes
Quaternary ammonium compounds
Halogen releasing agents
Which are the two main classes of halogen releasing agents used in microbial control?
Iodine-releasing
Chlorine-releasing
Bromine-releasing
Fluorine-releasing
What is the active concentration of alcohol? (at which it disrupted cell components)
40-60%
60-80%
80-100%
20-40%
Which of the following is true of phenolic compounds?
They often stain
They are toxic at high concentrations
They act as a local anesthetic at low concentrations
They form chlorinated bases in DNA
Who formally demonstrated the theory of germs?
Louis Pasteur
Robert Koch
Rudolf Emmerich and Oscar Loew
Paul Ehrlich
Which of the following are not part of Koch's postulates on the causal relationship between microorganisms and disease.
The microorganism must be found in all organisms suffering from the disease, and in healthy organisms.
The microorganism must be re isolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.
The cultured microorganism should cause disease when introduced into an immunocompromised organism.
The microorganism must be isolated from a diseased organism and grown in pure culture.
Who won the nobel prize for the showing prontosil red had antibacterial properties?
Rudolph Emmerich & Oscar Loew
Alexander Fleming
Gerhard Domagk
Which cell process does penicillin inhibit?
Protein synthesis
DNA gyrase
Cell wall synthesis
Folic acid metabolism
How many patients were affected by nosocomial infections in Europe in 2011?
14 billion
14 million
1.7 billion
1.7 million
Which of the following is a cause of antibiotic resistance?
Farming industry
Pets
Agriculture
Aquaculture
Human misuse
Which of the following is not a property of an ideal antibiotic?
Non-toxic/inert
Stable
Cheap (relatively)
selectively distrubuted
How do D,D-transpeptidases act in peptidoglycan cell wall synthesis?
Covalently bind murNAc and glcNAc together
Catalyses the formation of cross-links between D-ala side chains
Inhibit peptide binding proteins
Bind to the beta-lactam ring of beta-lactam antibiotics
Overproduction of MexAB-OprM gives imipenem resistance.
Which of the following is not a way that beta-lactam resistance can form?
Change in Pencillin Binding protein pathway
Modification of beta-lactam molecules
The binding of beta-lactamases to beta lactams using a catalytic serine
Mutation of PBPs
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