1 Dr. Katie\'s first stop was the Yellowstone National Park, with the largest si
ID: 216350 • Letter: 1
Question
1 Dr. Katie's first stop was the Yellowstone National Park, with the largest single concentration of hot springs and geothermal vents in the world are found. Some prokaryotes are specially adapted to grow in these environments. In each case we find a zonation of microorganisms according to their temperature optima. Often these organisms are colored, due to the presence of photosynthetic pigments or carotenoid pigments (yellows and browns). There she sampled some of the prokaryotes she found. Her next stop was the Dead Sea. The dead sea is 377 m (1,237 ft) deep, the deepest hypersaline lake in the world. With 33.7% salinity, it is also one of the world's saltiest bodies of water, and is 9.6 times as salty as the ocean. This salinity makes for a harsh environment in which animals cannot flourish. There she sampled huge mats of thriving prokaryotes down there--and the researchers have never seen bacteria that can survive in these conditions before. A) What are the two types of prokaryotes you would expect Katie to find in her samples? B) Which one do you think she is more likely to find? C) Explain what is special about prokaryotes that allow them to survive in environments that are too harsh for anything else. D) Explain how Katie will be able to tell if she is looking at prokaryotes and not eukaryotes.
Explanation / Answer
Answer:
(A) Bacteria and archaea are the two types of prokaryotes you would expect Katie to find in her samples.
(B) Many of the prokaryotes that grow in the most extreme environments are archaea
(C) Archaea have a more stable membrane chemistry than bacteria and eukaryotes have, which maymake them better able to survive in extreme environments.
Archaebacteria have cell membranes made of ether-linked phospholipids, while bacteria and eukaryotes both make their cell membranes out of ester-linked phospholipids. Archaebacteria use a sugar that is similar to, but not not the same as, the peptidoglycan sugar used in bacteria cell membranes.
(D) The main difference between the two cells is that prokaryotic cells basically have no nuclei, whereas eukaryotic cells do have true nuclei (easily identifiable dark object in the center of a cell).
Eukaryotic cells are larger (10micrometer) and more complex than the prokaryotic cells (<5 micrmeter).
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