内质网是许多细胞器的来源,如()都可能是内质网转化或分离的小泡而来。A、高尔基体 B

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问题:

内质网是许多细胞器的来源,如()都可能是内质网转化或分离的小泡而来。

A、高尔基体

B、核糖体

C、溶酶体

D、线粒体

E、中心粒

F、微管

考点:生物学普通动物学普通动物学题库
题型:多项选择题

吗啡常用于治疗急性肺水肿,其机制不包括()

A.扩张全身静脉

B.扩张小动脉

C.镇静

D.减低肺血管通透性

E.增加ANP释放而加强利尿

题型:多项选择题

建设项目在主体工程开工之前,必须完成各项准备工作,其主要工作内容包括( )。

A.施工现场的征地、拆迁

B.完成施工用水、电、气的通畅以及路和场地的平整(简称“三通一平”)

C.必需的生产、生活临时建筑工程

D.组织招标设计、咨询、设备和物资采购等服务

E.组织建设监理和主体工程招标投标,选定建设监理单位和施工承包队伍

题型:多项选择题

番泻叶粉末遇碱液显

A.红色

B.蓝色

C.黄棕色

D.暗紫色

E.污绿色

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Imagine eating everything delicious you want with none of the fat. That would be great, wouldn’t it

New "fake fat" products appeared on store shelves in the United States recently, but not everyone is happy about it. Makers of the products, which contain a compound called olestra, say food manufacturers can now eliminate fat from certain foods. Critics, however, say the new compound can rob the body of essential vitamins and nutrients and also cause unpleasant side effects in some people. So it’s up to consumers to decide whether the new fat-free products taste good enough to keep eating.

Chemists discovered olestra in the late 1960s, when they were searching for a fat that could be digested by infants more easily. Instead of finding the desired fat, the researchers created a fat that can’t be digested at all.

Normally, special chemicals in the intestines (肠道) "grab" molecules of regular fat and break them down so they can be used by the body. A molecule of regular fat is made up of three molecules of substances called fatty acids.

The fatty acids are absorbed by the intestines and bring with them the essential vitamins A, D, E and K. When fat molecules are present in the intestines with any of those vitamins, the vitamins attach to the molecules and are carried into the bloodstream.

Olestra, which is made from six to eight molecules of fatty acids, is too large for the intestines to absorb. It just slides through the intestines without being broken down. Manufacturers say it’s that ability to slide unchanged through the intestines that makes olestra so valuable as a fit substitute. It provides consumers with the taste of regular fat without any bad effects on the body. But critics say olestra can prevent vitamins A, D, E and K from being absorbed. It can also prevent the absorption of carotenoids (类胡萝卜素), compounds that may reduce the risk of cancer, heart disease, etc.

Manufacturers are adding vitamins A, D, E and K as well as carotenoids to their products now. Even so, some nutritionists are still concerned that people might eat unlimited amounts of food made with the fat substitute without worrying about how many calories they are consuming.

Why are nutritionists concerned about adding vitamins to olestra()。

A. People may be induced to eat more than is necessary.

B. It may trigger a new wave of fake food production.

C. It may lead to the over-consumption of vitamins.

D. The function of the intestines may be weakened.

题型:多项选择题

国际收支统计的数据来源主要由()

A.国际贸易统计

B.国际贸易报告统计

C.企业调查

D.官方数据源

E.伙伴国统计

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