What is the lecture mainly about? [br] Why does the professor mention insulin? [

游客2024-01-02  3

问题 What is the lecture mainly about? [br] Why does the professor mention insulin?
Listen to part of a lecture in a biology class.
    Professor:
    I’m sure most of you know that we’ve been able to extract certain compounds from plants for use in medicine. Eh, compounds like proteins from some plants can be used in medicines as antibodies in vaccines. And we can even cause some plants to produce certain proteins by incorporating DNA into the plant cells, usually in the leaves. We then extract the proteins to use as antibodies. However, we’ve never been able to produce enough protein to make the process worthwhile. It hasn’t been practical until now.
    Now it appears that it’s possible to get a large amount of usable protein from plants. Some researchers have recently succeeded in doing this by using plant seeds to produce these proteins rather than leaves or the other parts of the plant.
    Now there are a number of advantages to get protein from plant seeds to produce antibodies. But we have to be sure that these proteins are just as effective as human proteins. And so far the researchers show that antibodies produced from plant seeds protein are effective in humans, which is great. Because typically, antibodies for vaccines and medicines too are produced from micro-organisms like yeasts or bacteria, and it’s a rather complicated process.
    OK, so what makes plant seeds good production units? Well, for one thing, there are lots of them, right? One plant can produce a lot of seeds and then there is the issue of storage. Seeds can be stored for long periods of time and the protein retains its effectiveness.
    Now that’s not true with other parts of the plant. Leaves for instance, you can’t store them very long, which means you have to get that protein out right away as soon as it’s produced. But using plant seeds as production units allows you to isolate the protein whenever you need it, and you can transport seeds all over the world, even the places where refrigeration might be a problem, not so for yeasts and bacteria, but with seeds, it seems quite possible that we’ll be able to supply vaccine to places that need them. Whereas before this, transporting and preserving these products after a long distance simply wasn’t feasible. And another major benefit of extracting plant proteins for medical use is cost-effectiveness. Unlike the production of proteins for medicinal purpose using yeasts or bacteria like insulin which is a vital protein used in medications, extracting protein from seeds doesn’t require high-tech production labs with all kinds of equipment, and since refrigeration is not crucial for maintenance or transport, it’s just much less expensive to store and maintain plant seeds than other sources of protein. We estimate the total production cost to be 10 to 100 times lower.

选项 A、To give an example of a protein that is used as medicine
B、To point out the most common protein produced from plant seeds
C、To give an example of a medication that can be stored for a long period
D、To explain why it is difficult to extract proteins from plants

答案 A

解析 题目询问教授提及胰岛素的原因。在讲座最后,教授提到,酵母或细菌生产的蛋白质会被用于药用目的,而胰岛素的例子就是用于说明这一点,对应A项“举例说明胰岛索是一种用作药物的蛋白质”。B项“指出植物种子产生的最常见的蛋白质”、C项“举例说明胰岛素可以长时间储存”和D项“解释为何难以从植物中提取蛋白质”均没有依据。
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