2. 外语
  3. Some fish can swim in water below 0°C, low enough to freeze the blood of most creatures. However, some fish and insects can stay

Some fish can swim in water below 0°C, low enough to freeze the blood of most creatures. However, some fish and insects can stay

admin2015-01-31  38
问题     Some fish can swim in water below 0°C, low enough to freeze the blood of most creatures. However, some fish and insects can stay alive in the freezing water. One key to survival is a special protein in the fish’ s blood. The chemical is called the Antifreeze Protein, otherwise known as AFP and is commonly found in fish that live in cold waters.
    What does AFP do in these fish? First, we need to understand what happens when water freezes. When the temperature of the water drops below -1.0°C, tiny particles of ice start forming in the water. Each particle becomes larger and then sticks to other particles, forming blocks of ice. Fish take in this water and tiny particles of ice also form inside a fish’s body. However, the AFP in the blood of the fish surrounds these particles, preventing them from sticking together to form bigger pieces of ice.
    The application of AFP is promising. For example, AFP can be used to alter the taste and texture of ice-cream. It can also be used to store meat and vegetables more effectively by protecting food products from the formation of ice. Another application is in medical field, as AFP can help preserve organs for transplantation without freezing them. Scientists have known about AFP for more than 30 years, yet few of the technologies that use the AFP exist today. The process of getting the necessary amount of AFP from fish to make products was only recently discovered. Some companies in the United States and Canada have already made products using AFP, but they have yet to become popular. Although some researchers in Japan discovered that some local fish contained AFP and succeeded in creating AFP in the laboratory, more research is necessary. AFP tests will continue for these fish out of the water.
Why is AFP not widely used?
选项 A、It is only found in the blood offish that lives in colder seas.
B、The technology to utilize AFP has yet to be improved upon.
C、The protein will not be safe for another 30 years.
D、Countries such as Canada and Japan want to do more research first.
答案B
解析 细节题。短文第三段中间指出yet few of the technologies that use the AFPexist today即现在能利用AFP的技术还很少。故选项B正确。
转载请注明原文地址:https://kaotiyun.com/show/K5q7777K
0

大学英语四级

相关试题推荐
随机试题
最新回复(0)