Bacterial growth and control

Which of the following is NOT an environmental parameter that limits bacterial growth?

• Temperature

• pH

• Metabolism

• Osmotic pressure

• None of the above

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 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 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 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

What is the active concentration of alcohol? (at which it disrupted cell components)

• 40-60%

• 60-80%

• 80-100%

• 20-40%

Who formally demonstrated the theory of germs?

• Louis Pasteur

• Robert Koch

• Rudolf Emmerich and Oscar Loew

• Paul Ehrlich

Who won the nobel prize for the showing prontosil red had antibacterial properties?

• Rudolph Emmerich & Oscar Loew

• Paul Ehrlich

• 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 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

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