问题 填空题

荔枝叶片发育过程中,净光合速率及相关指标的变化间下表。

(1)B的净光合速率较低,推测原因可能是:①叶绿素含量低,导致光能吸收不足;②___________,导致_______________。

(2)将A、D分别置于光温恒定的密闭容器中,一段时间后,A的叶肉细胞中,将开始积累_________;D的叶肉细胞中,ATP含量将__________。

(3)与A相比,D合成生长素的能力________;与C相比,D的叶肉细胞的叶绿体中,数量明显增多的结构是_______________。

(4)叶片发育过程中,叶片面积逐渐增大,是______的结果;D的叶肉细胞与表皮细胞的形态、结构和功能差异显著,其根本原因是________。

答案

(1)气孔开放度相对低      二氧化碳供应不足

(2)酒精     增多

(3)低       基粒

(4)细胞分裂      基因的选择性表达

阅读理解

The weight-loss world is full of assertions①, rarely proved, that some pill can help you “burn calories while you sleep.” But a recent Dutch study reports that it can be done – simply by eating more lean protein②.

Researchers report for the first time that consuming nearly a third of daily calories as lean protein – for example, lean meats without the skin – speeds up a person’s metabolism③ during sleep and that higher protein intake increases the burning of calories and fat during the day. Plus, when the study’s participants, who were all women of healthy weight, ate more protein, they felt fuller, more satisfied and less hungry than when they consumed a diet with the amount of protein, about 10 percent of calories.

The findings suggest that adding lean protein to your daily food “enables you to reach the same level of satiety④that you are used to with about 80 percent of your normal energy intake,” notes Margriet Westerterp-Plantenga. “That means you can eat about 20 percent less and still have the same satiety.”

What gives protein its caloric edge? It’s more difficult for the body to metabolize protein than either fat or carbohydrates⑤. The body also doesn’t store protein as efficiently as it does carbohydrates or fat. So protein is more likely to be burned and that in turn requires more oxygen and helps you feel satisfied in the hours after eating.

But the latest findings don’t mean it’s time to dust off those high-protein diet books. The current study limited fat to about 30 percent of daily calories, and included 40 percent of calories as healthy carbohydrates, including fruit and vegetables. For example, lunch included bread, soy milk, fruit yogurt, tuna in water, tomatoes, cucumbers, feta cheese and salad dressing.

1. According the first paragraph, we know that ______.

A. there’re few studies on weight-loss in the world

B. many studies on weight-loss only cheat customers

C. only few studies are useful for weight-loss

D. there’re few studies about lean protein

2. According to the passage, lean protein can help burn calories while you sleep because ______.

A. it can slow down a person’s metabolism       B. it’s difficult for the body to metabolize

C. it will not make you feel full                D. it’s easy to be stored in the body

3. The underlined phrase “dust off” in the last paragraph means ______.

A. get rid of      B. put away      C. get ready to rewrite      D. get ready to reuse

4. The passage is mainly to tell readers ______.

A. there is a good diet for weight-losers

B. you can burn your calories in your sleep

C. high-protein diet books will be popular

D. choosing right food is of great use

单项选择题