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脂类的功能特性有哪些?

答案

参考答案:

脂类化合物是生物体内重要的能量储存形式,体内每克脂肪可产生大约39.7kJ的热量。机体内的脂肪组织具有防止机械损伤和防止热量散发的作用。磷脂、糖脂、固醇等是构成生物膜的重要物质。脂类化合物是脂溶性维生素的载体和许多活性物质(前列腺素、性激素、肾上腺素等)的合成前体物质,并提供必需脂肪酸。在食品中脂类化合物可以为食品提供滑润的口感,光洁的外观,赋予加工食品特殊的风味。脂类化合物在食品的加工或储存过程中所发生的氧化、水解等反应,还会给食品的品质带来需宜的和不需宜的影响。此外,过高的脂肪摄入量也会带来一系列健康问题,例如增加了患肥胖症、心血管疾病、癌症的风险。

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     A company planning to open the first hotel in space says it is on target to accept its first paying guests

in 2012 despite critics questioning the investment and the length of time for the multibilliondollar project.

     The Barcelonabased architects of the Galactic Suite Space Resort say it will cost $4.4 million for a

threenight stay at the hotel. This price also includes an eightweek training course on an island. During their

stay, guests would see the sunrise 15 times a day and travel around the world every 80 minutes.Galactic

Suite Ltd's CEO Xavier Claramunt says the project will put his company in a leading position of a new

industry with a huge future ahead of it, and forecasts space travel will become common in the future. "It's

very normal to think that your children, possibly within 15 years, could spend a weekend in space" he told Reuters Television.

     A promising space tourism industry is beginning to take shape with construction in progress in New

Mexico of Spaceport America, the world's first facility built specifically for passengers.  British

industrialist Richard Branson's space tours firm, Virgin Galactic, will use the facility to send tourists to

space at a cost of $200,000 a ride.

     Galactic Suite Ltd, set up in 2007, hopes to start its project with a single pod (分离舱) in orbit 280

miles above the earth. "It will take a day and a half to reach the pod, and the passengers will join it for

three days," Claramunt said. More than 200 people have expressed an interest in traveling to the space

hotel and at least 43 people have already reserved it.

     The numbers are similar for Virgin Galactic with 300 people already paid or signed up for the trip, but

unlike Branson, Galactic Suite says they will use Russian rockets to transport their guests into space from

a spaceport to be built on an island in the Caribbean. But critics have questioned the project, saying the

length of time that will be used is unreasonable and also where the money is coming from to support the

project.

1. What's Xavier Claramunt's attitude towards the space tourism industry?

A. Quite critical.     

B. Slightly worried.

C. Highly optimistic.  

D. Fully satisfied.

2. Virgin Galactic's guests will be transported into space by using rockets produced in________.

A. Spain  

B. America

C. Britain  

D. Russia

3. Which of the following is one of the critics' concerns about this project?

A. It is hard to ensure the safety of tourists.

B. There are many technical difficulties.

C. It will be a waste of resources.

D. It may lack support in money.

4. According to the passage, traveling to the space hotel ________.

A. will soon be possible for common people

B. has attracted the attention of some people

C. will make a large profit for the tourist industry

D. is considered an industry with a huge future by many people

5. What's the best title for the passage?

A. The world's first space hotel is to open in 2012.

B. The world's first commercial spaceport is being built.

C. Space tourism:a surprising new industry.

D. Space travel will become common in 15 years.