Discuss the role of bacteria in the (a) carbon and (b) nitrogen cycles
What will be an ideal response?
(a) Like all organisms, bacteria require organic molecules for energy, and during cellular respiration, they break the molecules down and release carbon dioxide. Many bacteria are decomposers and contribute to the breakdown of dead organisms, releasing some carbon dioxide to the atmosphere. Some bacteria are photosynthetic and can thus fix atmospheric carbon in much the same way that plants do. (b) Bacteria play a vital role in the nitrogen cycle. Almost 80% of Earth's atmosphere is nitrogen (N2), but it is an unreactive form of nitrogen and cannot be directly taken in and used by plants or animals. It is the job of nitrogen-fixing bacteria in soil and water to convert this nitrogen into ammonia and ammonium ions (NH3 and NH4+), which can then be converted to NO3- by nitrifying bacteria. Plants and algae can take up these reactive forms of nitrogen and incorporate the nitrogen into organic molecules such as proteins and DNA. Other bacteria convert the nitrogen-containing organic molecules from decomposing organisms back into ammonia. Finally, there are denitrifying bacteria that convert reactive forms of nitrogen back into unreactive atmospheric N2, completing the cycle.
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An individual coral animal is known as a(n) ________.
A. zooxanthella B. sponge C. zooxanthella or polyp D. alga E. polyp
Yugoslavia's nationality
A) was socially constructed through a heavy-handed authoritarian leadership. B) evolved naturally within the post-World War I political boundaries. C) accepted the dominance of Serbian culture and ethnicity. D) emerged only as a result of substantial economic growth. E) was a precursor to the effect of globalization on the region.
In order for a terrane to become attached to a continent, it typically
A. becomes scraped of a subducting plate. B. is shifted there suddenly by an earthquake. C. originated as a meteor that fell over a continent. D. is transported by a glacier. E. results from the collision of two continental plates.
The term "Anglo America" in reference to the United States and Canada is more relevant than ever today
Indicate whether the statement is true or false