Problem 1
Describe binary fission.
Problem 2
Macronutrients (needed in relatively large amounts) are often listed as CHONPS. What does each of these letters indicate, and why are they needed by the cell?
Problem 3
Define and explain the importance of each of the following: a. catalase b. hydrogen peroxide c. peroxidase d. superoxide radical e. superoxide dismutase
Problem 5
By deep-freezing, bacteria can be stored without harm for extended periods. Why do refrigeration and freezing preserve foods?
Problem 6
A pastry chef accidentally inoculated a cream pie with six \(S\). aureus cells. If \(S\). aureus has a generation time of 60 minutes, how many cells would be in the cream pie after 7 hours?
Problem 7
Nitrogen and phosphorus added to beaches following an oil spill encourage the growth of natural oil-degrading bacteria. Explain why the bacteria do not grow if nitrogen and phosphorus are not added.
Problem 9
Draw the following growth curves for \(E\). coli, starting with 100 cells with a generation time of 30 minutes at \(35^{\circ} \mathrm{C}\), 60 minutes at \(20^{\circ} \mathrm{C}\), and 3 hours at \(5^{\circ} \mathrm{C}\). a. The cells are incubated for 5 hours at \(35^{\circ} \mathrm{C}\). b. After 5 hours, the temperature is changed to \(20^{\circ} \mathrm{C}\) for 2 hours. c. After 5 hours at \(35^{\circ} \mathrm{C}\), the temperature is changed to \(5^{\circ} \mathrm{C}\) for 2 hours followed by \(35^{\circ} \mathrm{C}\) for 5 hours.
Problem 10
A prokaryotic cell hitched a ride to Earth on a space shuttle from some unknown planet. The organism is a psychrophile, an obligate halophile, and an obligate aerobe. Based on the characteristics of the microbe, describe the planet.
