组卷网 > 高中英语综合库 > 主题 > 人与自然 > 自然 > 动物
题型:阅读理解-阅读单选 难度:0.4 引用次数:435 题号:12743597

Biologists from the John Innes Centre in England discovered that plants have a biological process which divides their amount of stored energy by the length of the night. This solves the problem of how to portion out(分配) energy reserves during the night so that the plant can keep growing, yet not risk burning off all its stored energy.

While the sun shines, plants perform photosynthesis(光合作用). In this process, the plants change sunlight, water and carbon dioxide into stored energy in the form of long chains of sugar, called starch(淀粉). At night, the plants burn this stored starch to fuel continued growth.

“The calculations are precise so that plants prevent starvation but also make the most efficient use of their food,” said study co-author Alison Smith. “If the starch store is used too fast, plants will starve and stop growing during the night. If the store is used too slowly, some of it will be wasted.”

The scientists studied the plant Arabidopsis, which is regarded as a model plant for experiments. To give the plants some math tests, the biologists let night arrive unexpectedly early or late for them.

During one of the exams, they shut off the lights early on them that had been grown with twelve-hour days and nights. Putting them into darkness after only an eight-hour day means they didn’t have time to store as much starch as usual. And this forced the plants to adjust their normal nightly rhythm.

Amazingly, even after this day length trick, the plants did very well in their exams and ended up with just five percent of starch left over at the end of the night. They had neither starved, nor stored starch that could have been used to fuel more growth.

The authors suggested that similar biological calculators may explain how a migratory bird, the little stint, can make a five-thousand-kilometer journey to their summer habitat in the Arctic and arrive with enough fat reserves to survive only approximately half a day more, on average.

The results of the study were published in e Life.

1. According to the passage, plants _________.
A.use little energy during the day
B.usually stop growing at night
C.waste a lot of energy at night
D.store starch during the day
2. What did the scientists do when studying Arabidopsis?
A.They changed the plant’s light conditions.
B.They provided the plant with more starch.
C.They tried to keep the plant’s natural rhythm.
D.They attached a biological calculator to the plant.
3. When morning arrived, the experimental plants ________.
A.nearly died of lack of food
B.used most of their stored energy
C.began to regulate their food store
D.stored enough starch for the next day
4. What can we learn about the little stint?
A.They may have a system to control energy consumption.
B.They often die during their long and difficult journey.
C.They leave the Arctic in summer every year.
D.They are unable to calculate the distances.
5. The passage mainly tells us _________.
A.plants feel hungrier day by day
B.plants are good at storing energy
C.plants do math to survive the night
D.plants use starch to fuel their growth

相似题推荐

阅读理解-阅读单选(约290词) | 较难 (0.4)
【推荐1】

Everybody hates rats. But in the earthquake capitals of the world—Japan, Los Angeles, Turkey—rats will soon be man's new best friends.

What happens after an earthquake? We send in rescue dogs. Why? Because they can smell people. Dogs save lives. They help rescuers to find living people. But dogs are big and they can't get into small spaces. So now a new research project is using a smaller animal to save lives: the rat.

How does it work? First, the rat is trained to smell people. When this happens, the rat's brain gives a signal (信号). This is sent to a small radio on its back, and then the rescuers follow the radio signals. When the rat's brain activity jumps, the rescuers know that someone is alive. The rat has smelled that person.

Although there are already robots which can do this job, rats are better. Christian Linster at Cornell University, New York, says, "Robots' noses don't work well when there are other smells around. Rats are good at that." Rats can also see in the dark. They are cheaper and quicker to train than dogs, and unlike robots, they don't need electricity!

The "rat project" is not finished, but Julie Ryan of International Rescue Corps in Scotland says, "It would be fantastic. A rat could get into spaces we couldn't get to, and a rat would get out if it wasn't safe." Perhaps for the first time in history, people will be happy to see a rat in a building (but only after an earthquake, of course).

1. In the world earthquake capitals, rats will become man's best friends because they can ________.
A.take the place of man's rescue jobs
B.find the position of people alive who are trapped in buildings
C.serve as food for people alive who are trapped in buildings
D.get into small spaces
2. From the third paragraph we know the rescuers can judge a person is alive by ________.
A.the noise made by the rat
B.the rat's unusual behaviour
C.the signal sent by the radio on the rat's back
D.the smell given off by the person
3. After reading the passage we know ________.
A.at present rats have taken the place of dogs in searching for people
B.the "rat project" has been completed
C.people are now happy to see a rat in a building
D.now people still use dogs and robots in performing rescues
2021-10-16更新 | 79次组卷
阅读理解-阅读单选(约280词) | 较难 (0.4)
名校

【推荐2】Every spring flowers suddenly come out everywhere on the same day, as if they had an agreement with one another. But how exactly do plants “know” when to flower?

It’s a question puzzling biologists for years. But according to Science Daily, a US research group may have finally answered it—the secret lies in a protein called FKF1. This allows plants to sense the differences in day lengths so that they can tell the seasons are changing.

Researchers found the protein when they were studying a plant called Arabidopsis. They found it’s a photoreceptor (感光器). This means it’ s sensitive to, and can be activated (激活) by sunlight.

Plants produce the protein every day in the late afternoon throughout the year. If there’s no light at this time, for example, in winter when the sun goes down early, it may not be activated. But when spring comes and the days get longer, it can be activated by daylight and the plants “know” it’s time to flower.

Although researchers have only studied how the FKFI protein works in the Arabidopsis, they believe that the process is similar in many other more complex (复杂) plants, including crops like rice and wheat. This could be useful to the agricultural industry.

“If we can control the timing of flowering, we might be able to produce more crops by putting it forward or putting it off,” a leader of the study said. “Also, if we could control the timing of flowering in horticultural (园艺的) plants, they may be worth more money.”

What an amazing thing to think about this!

1. How do plants know when to flower?
A.They get messages from some insects.
B.They receive messages from other plants.
C.A certain protein tells them the time to flower.
D.Sunlight produces a protein in them to help them flower.
2. What can we learn from the article?
A.The study may benefit agricultural industry.
B.We may have plants that flower all year round.
C.Plants don’t flower in cold weather and short days.
D.Researchers found the protein by studying rice and wheat.
3. What’s the writer’s attitude towards the study?
A.Negative.B.Positive.
C.Uncaring.D.Unclear.
2019-09-19更新 | 144次组卷
阅读理解-阅读单选(约380词) | 较难 (0.4)
名校
文章大意:本文是一篇说明文。文章主要讲述大熊猫的肠道细菌可以帮助他们吸收竹子中的营养。

【推荐3】Pandas are famously picky eaters. They only consume bamboo — a poor quality diet low in fat. But the creatures appear to have evolved to get the most out of what they do eat, according to a new study.

Their gut (肠道) bacteria change in late spring and early summer when bamboo is at its most nutritious — while protein-rich green shoots are coming out. The bacteria make the panda gain more weight and store more fat, which researchers said may compensate for a lack of nutrients later in the year, when bamboo plants have only fibrous leaves to chew.

“We’ve known these pandas have a different set of gut microbiota during the shoot-eating season for a long time, and it’s very obvious that they are chubbier during this time of the year,” said lead study author Guangping Huang, a researcher for the Institute of Zoology at the Chinese Academy of Sciences.

To investigate how the gut bacteria could affect a panda’s digestion, the team first collected the wastes of eight wild giant pandas in China’s Qinling Mountains during both leaf eating season and shoot-eating season and then examined how the waste samples differed. They found a bacterium called Clostridium butyricum was more abundant in the pandas’ guts during the season when they enjoy the fresh bamboo shoots.

To understand whether this bacterium helps the pandas gain and store weight, the researchers put the panda wastes they collected into lab mice. Then they fed the mice for three weeks with a bamboo-based diet that simulated (模仿) what pandas eat. Researchers found the mice which were transplanted with panda wastes collected during shoot-eating season gained significantly more weight than the ones which were not, despite consuming same amount of food.

“The gut bacteria were the only variable (变量) in this research,” Wei explained. However, Felix Sommer at Christian-Albrechts-University in Kiel, Germany, noted the number of pandas studied was small and that the experiment had only been performed once. Sommer also stressed the researchers had found a link, not a causal relationship between the bacteria and weight gain.

1. When do pandas get more weight with the change of their gut bacteria?
A.In late spring.B.In late summer.C.In early autumn.D.In early winter.
2. What does the underlined word “chubbier” in paragraph 3 mean?
A.Smaller.B.Slimmer.C.Taller.D.Fatter.
3. What can we learn from the experiment on mice?
A.The experiment lasted for less than three weeks.B.Researchers collected bacteria from the lab mice.
C.Panda wastes have a vital effect on mice’s weight.D.Different amounts of food led to an increase in weight.
4. What is the best title for the text?
A.Studies on Eating Habits of PandasB.Functions of Pandas’ Gut Bacteria
C.Characteristics of Pandas’ Daily DietD.Arguments over Pandas’ Digestion System
2022-04-02更新 | 262次组卷
共计 平均难度:一般