生物学 TPO26-L2 Carbon Cycling

TPO26-L2

Carbon Cycling

Listen to part of a lecture in a biology class.

 



  1. What is the lecture mainly about?
  • A. The discovery of a previously unknown trace metal.
  • B. The role trace metals play in carbon cycling.
  • C. Ways that living organisms rid themselves of trace metals.
  • D. Ways that zinc interacts with carbon dioxide.

 

  1. What does the professor imply about the conversion of carbon dioxide molecules in plants?
  • A. It is an unusually complex chemical process
  • B. It only takes place in full sunlight
  • C. It proceeds slowly when cadmium is present
  • D. It is regulated by an enzyme that may contain zinc

 

  1. According to the professor, why is it surprising that many marine plants are able to survive near the surface of oceans?
  • A. Weather conditions near the surface disrupt certain life processes.
  • B. The salt content of surface waters is constantly changing.
  • C. Surface waters contain low quantities of zinc.
  • D. Surface waters absorb large amounts of carbon dioxide.

 

  1. According to the professor, what important function do diatoms serve?
  • A. They alter cadmium so it is less toxic to humans.
  • B. They help cycle zinc in places where it is scarce.
  • C. They distribute carbon throughout the ocean.
  • D. They remove cadmium from the ocean floor.

 

  1. What point does the professor make when she talks about cadmium being poisonous to humans?
  • A. That cadmium and zinc can serve a similar function in plant enzymes.
  • B. That both cadmium and zinc are rare in plant enzymes.
  • C. That most trace metals are poisonous to humans.
  • D. That cadmium does not serve any biological purpose.

 

  1. The professor states that the discovery of an enzyme containing cadmium is important. What are two reasons that this discovery is important?
    [CHOOSE 2 ANSWERS]
  • A. It may lead to the discovery of new enzymes that use other trace metals.
  • B. It may explain the ocean’s increased level of carbon dioxide.
  • C. It may explain the scarcity of some elements in the ocean.
  • D. It may help scientist better understand global warming.


答案:
B D C C A AD

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