Question 1
What is the source of the acidic pH of some mine runoff?
◦ Pyrite is oxidized by exposure to the atmosphere and microbes.
◦ Iron ores are reduced by exposure to the atmosphere.
◦ Iron ores contain sulfuric acid (H
2SO
4).
◦ Hydrogen gas trapped in ore reacts with the atmosphere to produce hydrochloric acid (HCl).
◦ Sulfur-containing ores are reduced by exposure to oxygen.
Question 2
Which of the following statements concerning the phosphorus cycle in bacteria is TRUE?
◦ It is the most important process for synthesizing proteins and nucleic acids.
◦ The element alternates among several oxidative states.
◦ The element cycles between different organic molecules.
◦ The element is converted to a gaseous state and is lost to the environment.
◦ The element changes from insoluble to soluble forms.
Alternation of generations, the plant life cycle
Major reservoirs and flows of the hydrological cycle.
Fern Life Cycle
DNA supercoiling in bacteria
Polyribosomes in bacteria
Mechanisms of Transcription Regulation in Bacteria