What is the lecture mainly about? [br] Why does the professor discuss refrigerat

游客2025-02-04  1

问题 What is the lecture mainly about? [br] Why does the professor discuss refrigeration?
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 emphasize the expense of producing proteins from plant seeds
B、To point out the cost-effectiveness of transporting seeds
C、To illustrate the difficulty of preserving some vaccines made from seed proteins
D、To emphasize the need for more high-tech laboratories for extracting plant proteins

答案 B

解析 题目询问教授讨论冷藏的原因。在讲座的最后,教授提到了cost effectiveness“成本效益”,并指出“由于冷藏并不是保存和运输的必要条件,所以保存植物种子的成本比保存其他蛋白质来源的成本要低得多”,对应B项“指出运输种子的成本效益”。A项“强调植物种子生产蛋白质的费用”有所偏差,教授讨论冷藏更多地是想说明利用植物种子生产蛋白质的成本效益高,与费用、保存、运输相关,但A项仅强调了费用方面,范围较窄。C项“说明保存一些由种子蛋白质制成的疫苗的困难”,录音说的是利用种子蛋白质制疫苗方便,因为不用担心储存问题,可在有需要时才进行蛋白质分离操作,故C项错误。D项“强调需要有更多提取植物蛋白的高科技实验室”与冷藏无关。
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