Cells may enter stationary phase because of

Q1. Evaluate the statements below and choose those that correctly apply the hypotheses that account for cell members during the death phase and long-term stationary phase of microbial growth curve

Cell death in a batch culture can be attributed to a lack of nutrients and a build up of metabolic waste products that are toxic to the cell. A decline in cell number during the death phase is observed with cells grown in a batch culture. The ability of some cultures to enter a long-term stationary phase reflects “survival of the fittest” in a closed system. Microbes can enter a long term stationary phase if some organisms are able use the metabolic biproducts as fuel

Q2 In industry, microorganisms are often cultured in an environment where ideal conditions are maintained through continual nutrient provision and waste renewal. Such a system is called a

Continuous culture

 Q3 Rank the following events in the development of antimicrobial drugs in chronological order.

  1. Salvarsan was first used against Treponema pallidum, that causes syphilis.
    2. Mice treated with the dye Prontosil red were protected against pathogenic Staphylococci and Streptococci.
    3.Alexander Fleming rediscovered the antibacterial properties of penicillin.
    4.A new antibiotic produced by Streptomyces griseus was discovered by Waksman.

 Q4. If a new antifungal drug was discovered that had low selective toxicity and a high therapeutic index, what assumptions could be made about the drug?

The drug targets an essential molecule in fungi that is not present in a human cell.

Q5. In a chemostat, both the microbial population level and the generation time are related to the dilution rate. (T/F)


Q6 In which of the following aspects of the cell cycle is Sulfolobus similar to eukaryotes?

There is an extended G2 phase before segregation of the daughter chromosomes

Cytokinesis using proteins in the ESCRT family

Conserved replicative DNA polymerase

Q7 Cells may enter stationary phase because of

a lack of oxygen, the accumulation of toxic waste products, the depletion of an essential nutrients

Q8. Gamma radiation

used to sterilize some food products

Q9 As the growth rate constant increases the generation time decreases. (T/F)



 q10 You are working with strains of Zymomonas mobilis to select the best strain for bioethanol production. You are trying to find the strain that requires the shortest time to grow. If the strains have the following growth rate constants, which would you choose to meet your criteria?


Q11  if you design a new compound that inhibits the growth of bacteria then you would call it bacteriostatic. What would you call a compound that kills the bacteria?


Q12 Antibiotics that are given by injection are said to have a(n) __________ route of administration.
A. oral
B. venal
C. parenteral
D. topical


Q13 Examine the accompanying graph that illustrates the decrease in surviving cells when exposed to three different temperatures, represented by plots A, B, and C. Which of the following statements represents a valid interpretation of the data in this graph?


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Exposure to specific antibiotics is a blank force that helps maintain the resistance gene in a population of bacteria.