You are a scientist on board on a mission exploring undersea volcanic vents arou
ID: 181676 • Letter: Y
Question
You are a scientist on board on a mission exploring undersea volcanic vents around the Hawaiian Islands. On your expedition ship you have a fully equipped laboratory (like our new building will be) where you can do advance microscopy, cellular biology and biochemical characterization of the life forms you encounter You encounter a NEW unicellular EUKARYOTIC organism This organism thrives in the following conditions: The temperature is 78 degree C The Oxygen content is extremely low The sulfur content is very high, and it lives in complete darkness. The organism has the ability to metabolized sucrose, and is capable of producing ATP The organism is capable of maintaining a resting potential of about -60 mV. and it also quickly eliminates xenobiotics This organism has the ability to form multicellular aggregates when exposed to stressful conditions such as a decrease in the temperature below 50 degree C: you observed that when the temperature dropped all the cells appear to migrate towards a clump of cells that eventually congregated all the cells and started to creep on the bottom of the cell culture dish towards a source of light! You discover that if you constantly change the sea-water around it, you inhibit the formation of the multicellular aggregates. Based on these observations, and what you have learned in this course and please discuss the following What sort of cell membrane does this organism have? What type of energy metabolism does it have? What are the enzyme activity profiles in relation to temperature? How does it maintain a constant electrochemical potential? What is the signaling method used to communicate and form multicellular aggregates?Explanation / Answer
Answers:
(1) The organism is a thermophile as it can survive at high temperature (78C). The cell membrane in this organism is composed of highly saturated fatty acids which helps it to maintain their integrity at high temperatures.
(2) The organism can survive in high sulphur environment and can metabolize sucrose and form ATP. So, it appears to be a chemoheterotroph, since it can derive energy through oxidation of sulphur and can also metabolize sucrose.
(3) The enzyme activity profile of the organism in relation to temperature appears to follow a dumb bell curve where the maximal enzyme activity is around 78C with a gradual decrease in activity above or below this temperature.
(4) The electrochemical potential in the organism is maintained through specific integral membrane proteins which transfer ions across the cell membrane to the exterior in an energy dependent process. The activity of these pumps which basically deals with protons and sodium ions results in the generation of electrochemical gradients. Active pumping of protons to the cell exterior creates a electrical potential with inside more negative than outside.
(5) The collective behavior of the organism appears to be due to a mechanism similar to "Quorum sensing" found in bacteria where the individual cells release the signaling molecule to attract other cells and form aggregates.
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