Microbiology Test-2 Review

This set of flashcards is designed to help students review key concepts and facts from their microbiology lecture notes in preparation for Test 2.

What media is best for isolating lactose fermenting organisms?

EMB (Eosin Methylene Blue agar) is used for this purpose.

True or False: During the lag phase of microbial growth, the cells are metabolically inactive.

True.

Why must ampicillin be administered by injection?

Because it is rapidly degraded in the stomach and cannot be given orally.

Which components are associated with the eukaryotic cytoskeleton?

Actin filament, alpha-tubulin, and intermediate filaments.

True or False: Aerobic organisms produce protective enzymes called superoxide dismutase and catalase.

True.

What is the term for the destruction or removal of all viable organisms?

Sterilization.

What type of organisms are fungi?

Heterotrophic.

What is the term for the killing of vegetative forms of pathogenic microorganisms on inanimate objects?

Disinfection.

What influences the efficiency of an antimicrobial agent?

Concentration of the agent, duration of exposure, and temperature.

True or False: Protein synthesis inhibitors have a low therapeutic index because they cannot discriminate between prokaryotic and eukaryotic ribosomes.

True.

What can be found in mitochondria?

Membrane, ribosome, and DNA.

What type of agent inhibits bacterial growth without killing bacteria?

Bacteriostatic agent.

Which sterilization procedure utilizes the size of microorganisms?

Filtration.

True or False: Alcohols are used as antiseptics and disinfectants due to their effectiveness against bacteria and viruses.

True.

True or False: The rate of killing by an antimicrobial may slow with a reduced microbial population.

True.

What sterilizing gas can be used on heat-sensitive materials?

Ethylene oxide.

Which antibiotic is a beta-lactam antibiotic?

Ampicillin.

What are characteristics of fungi?

They produce mycelium and have cell walls containing chitin.

Which can degrade protein in eukaryotic microorganisms?

Lysosome and proteasome.

Which antibiotic can be prescribed for Gram-positive bacteria?

Ampicillin, cephalosporin, or vancomycin.

Which antibiotic is broad spectrum?

Ampicillin.

Who introduced the concept of selective toxicity?

Paul Ehrlich.

Which organisms are sources of antibiotics?

Streptomyces, Micrococcus, and Cephalosporium.

What is the function of pasteurization?

Reducing the total microbial population.

Which antibiotic is least stable in stomach acidity?

Penicillin G.

What must the concentration of a drug be in order to be effective?

Higher than the pathogen's minimal inhibitory concentration (MIC).

Which drug treats systemic fungal infection?

Amphotericin B.

What drug treats herpes virus infection?

Acyclovir.

What method determines the growth of microorganisms?

Light scattering in a spectrophotometer.

True or False: Size and shape of a colony are not useful for identifying microorganisms.

True.

Why is agar used in microbiological media?

It is not degraded by most microorganisms.

What is the best method to isolate pure cultures of oxygen-sensitive bacteria?

Pour plates.

What type of culture operates without the addition of media?

Batch culture.

Why does the total number of viable microorganisms remain constant in stationary phase?

Balance between cell division and cell death.

What percentage of the microbial population may be eliminated through heat?

99%.

What is an open system that maintains growth rate by removing and adding media?

Chemostat.

What term is used for organisms that do not require oxygen but grow better in its presence?

Facultative anaerobes.

What fatty acids help psychrophilic bacteria remain semi-fluid at low temperatures?

Unsaturated fatty acids.

What can cause a lag phase in bacterial growth?

Cells being old, medium differences, or injury requiring recovery.