2016年3月19日托福阅读真题+题目+答案：Bioluminescence in Marine Creatures

2016年3月19日托福阅读真题+题目+答案：Bioluminescence in Marine Creatures 

At night along the sea’s edge, the ocean sometimes seems to glow, as if lit from within. This glow is the result of bioluminescence, a phenomenon exhibited by many of the sea’s zooplankton. Bioluminescence is the production of cold light through internal biological processes, as opposed to phosphorescence or fluorescence, both of which are re-emitted light that was initially absorbed from an external source.

Many of the sea’s creatures, including squid, dinoflagellates, bacteria, worms, crustaceans, and fish, are known to produce light. The process that marine creatures use to create light is like that of the common firefly and similar to that which creates the luminous green color seen in plastic glow sticks, often used as children’s toys or for illumination during nighttime events. When a glow stick in bent, two chemicals mix, react, and create a third substance that gives off light. Bioluminescent organisms do essentially the same thing; they have a substance, called luciferin, that reacts with oxygen in the presence of enzyme, luciferase. When the reaction is complete, a new molecule is formed that gives off light—glowing blue—green in the underwater world. This biologically driven chemical reaction occurs within the organism’s special light-producing cells, called photocyptes, or light-producing organs, called photophores. Probably one of the most complex light-producing systems is that of the squid. Some squid have both photophores and chromatophores (organs for changing color) with their skin, thus enabling them to control both the color and intensity of the light produced. Recent research has also revealed that in some squid and fish, bioluminescent light may be produced by bacteria that live in a mutually beneficial partnership inside the animal’s light organs.

1. Why does the author mention the common firefly in the passage?

A. To relate the light production of marine creature to that of a familiar light-producing species

B. To compare the light production of an insect with the more complex light production of marine creatures

C. To provide an example of a species that does not use a chemical reaction to produce light

D. To support the point that bioluminescence usually occurs at night

2. Which of the following statements about the chemical reaction that produces bioluminescence is NOT true, according to paragraph 2?

A. It occurs when luciferin reacts with oxygen.

B. It produces a glowing blue-green light.

C. It is much like the process by which children’s toys are illuminated.

D. It requires organs called chromatophores.

3. Paragraph 2 demonstrates the complexity of certain squid by stating that

A. the squid employs its bioluminescent light to prevent bacteria from entering its organs

B. the squid controls both the color and intensity of the light it produces

C. the squid’s light has greater intensity than that of fish

D. the squid produces the enzyme luciferase when it produces light

4. The phrase “mutually beneficial” in the passage is closest in meaning to

A. helpful to one another

B. generally practical

C. efficiently balanced

D. temporary by design

5. Which of the following statements about bioluminescent creatures is implied by paragraph 2?

A. Bioluminescent creatures cannot produce light if bacteria enter their light organs.

B. Not all bioluminescent creatures have both photophores and chromatophores.

C. Most bioluminescent organisms do not need the enzyme luciferase in order to produce light.

D. Creatures with light-producing organs are much more common than those that have only light producing cells.

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