You are a scientist on board on a mission exploring undersea volcanic vents arou
ID: 83150 • 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 advanced 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° C -The Oxygen content is extremely low -The sulfur content is very high, and it lives in complete darkness. -The organism and is capable of producing abundant ATP (but the mitochondria seem odd….) -The organism is capable of maintaining a resting potential of about -60 mV, and it also quickly eliminates xenobiotics using a co-transport mechanism depending on Na gradients. -This organism has the ability to “creep “ on the bottom of culture dishes using amoeboid like movements, and seems to be attracted to decaying organic matter (It creeps towards it !!!!) However if you constantly change the sea-water around the cells, they become “disoriented” and move randomly instead of towards the decaying piece of fish… Based on these observations, and what you have learned in this course and please discuss the following 1) What would be the composition of the cell membrane composition? 2) What type of energy metabolism would it it have? 3) What would the enzyme activity profiles in relation to temperature look like? pH (think about the environment it is in…) 4) How does it maintain a constant resting potential, and, use it for Xenobiotic transport? 5) Speculate on how these microorganisms detect the decomposing piece of shrimp…(or fish…)? Hypothetical Scenario
Explanation / Answer
According to the information, the answers can be found as below:
Part 1) What would be the composition of the cell membrane composition?
Answer: Since the cell resides in an environment with too high ambient temperature and sulphur concentration, it must contain a very functional plasma membrane with discrete membrane and channel protein with high meltine points accomodated with highly fluid phospholipid bilayer in order to maintain fluidity for aiding membrane transport.
2) What type of energy metabolism would it it have?
Answer: Since the microbe prefers dark, anaerobic conditions, it must be dependent upon sulphur-metabolism or anaerobic metabolism for generation of energy by consuming decaying organic matter. This mode is similar to saprophytic mode of nutrition but takes place at higher or extreme temperature.
3) What would the enzyme activity profiles in relation to temperature look like? pH (think about the environment it is in…)
Answer: Normally, the enzyme activities fall with increase in temperature beyond 37-38 degree celcius. However for the present microbe, the enzyme activity will be very high at temperatures ranging upto 75-80 degree celcium becuase this is the range of normal ambient temperature for them. Further, since the microbe resides in high sulphur containing medium, it must be highly acidic in nature. The low pH increases the acidity of the intracellular environment of the microbe and hence
4) How does it maintain a constant resting potential, and, use it for Xenobiotic transport?
Answer: The microbe must be able to maintain an electro-chemical gradient across its membrane by regulating the movement of ions across the plasma membrane in order to maintain a constant resting potential. Any change in this resting potential can be directly utilized by the microbe must contain some surface bound receptor protein channels which are stable at such harsh environmental conditions and constantly engaged in removal of xenobiotics from the cell.
5) Speculate on how these microorganisms detect the decomposing piece of shrimp…(or fish…)? Hypothetical Scenario
Answer: The microbe shows chemotaxis and hence it can easily move towards a decomposing piece of organic matter due to chemical attraction between itself and the target. This is a common microbiological phenomenon shown by many microbes which show extreme behaviours.
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