Concept explainers
One Tough Bug The genus Ferroplasma consists of a few species or acid-loving archaea. One species, F. acidarmanus, was discovered to be the main constituent of slime streamers (a type of biofilm) deep inside- an abandoned California copper mine (FIGURE 5.36). These cells use an ancient energy-harvesting pathway that combines oxygen with iron-sulfur compounds in minerals such as pyrite. Oxidizing these minerals dissolves them, so groundwater that seeps in to the mine ends up with extremely high concentrations of metal ions such as copper, zinc, cadmium, and arsenic. The reaction also produces sulfuric acid, which Lowers the pH of the water around the cells to zero.
F. acidarmanus cells maintain their internal pH at a cozy 5.0 despite living in an environment similar to hot battery acid. Thus, researchers investigating Ferroprasma were surprised to discover that most of the cells' enzymes function best at very low pH (FIGURE 5 .37).
FIGURE 5.36 Deep inside one of the most toxic sites in the United States:
Iron Mountain Mine, in California. The water in this Stream, which is about 1 meter (3 feet) wide in this view, is hot (around 40°C, or 104°F), heavily laden with arsenic and other toxic metals, and has a pH of zero. The slime streamers growing in it are a biofilm dominated by a species of archaea Ferropiasma acidarmanus.
FIGURE 5.37 pH anomaly of Ferroplasma acidarmanus enzymes. The graphs (right) show the pH activity profiles of four enzymes isolated from Ferroplasma. Researchers had expected these enzymes to function best at the cells' cytoplasmic pH (5.0).
2. Of the four enzymes profiled in the graph, how many function optimally at a pH lower than 5? How many retain significant function at pH 5?
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Chapter 5 Solutions
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- The genus Ferroplasma consists of a few species of acid-loving archaea. One species, F. acidarmanus, was discovered to be the main component of slime streamers (a type of biofilm) deep inside an abandoned California copper mine (Figure 4.11A). F. acidarmanus cells use an ancient energy-harvesting pathway that combines oxygen with ironsulfur compounds in minerals such as pyrite. This reaction dissolves the minerals, so groundwater that seeps into the mine ends up with extremely high concentrations of metal ions such as copper, zinc, cadmium, and arsenic. The reaction also produces sulfuric acid, which lowers the pH of the water around the cells to zero. Despite living in an environment with a composition similar to hot battery acid, F. acidarmanus cells maintain their internal pH at a cozy 5.0. Thus, researchers investigating Ferroplasma metabolic enzymes were surprised to discover that most of the cells enzymes function best at very low pH (Figure 4.11B). A. Deep inside one of the most toxic sites in the United States: Iron Mountain Mine, in California. The water in this stream, which is about 1 meter (3 feet) wide in this photo, is hot (around 40C, or 104F), heavily laden with arsenic and other toxic metals, and has a pH of zero. Slime streamers growing in it are a biofilm dominated by a species of archaea, Ferroplasma acidarmanus. B. pH profiles of four enzymes isolated from F. acidarmus. Researchers had expected these enzymes to function best at the cells cytoplasmic pH (5.0). What does the dashed line signify?arrow_forwardSuppose you are given a container that has a membrane permeable only to metabolic wastes. The container is filled with 5 M metabolic waste in an aqueous solution. You wish to reduce the amount of waste dissolved in the container. You see a 5 L beaker of pure water sitting across the room on a shelf. What is your plan?arrow_forwardAutotrophs harvest energy directly from the environment and store it in the form of sugars and other carbohydrate. They and all other organisms use energy stored in sugars to power various endergonic reactions that sustain life. Identify the two cellular process responsible for products described in the figure. Explain the role of each product listed in the processes. A prolonged drought with record-breaking temperatures occurs in the Pacific Northwest. Predict the impact on the cellular processes described in the figure. Justify your response.arrow_forward
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