题干

对某种动物的肝肿瘤细胞进行细胞培养。下列说法错误的是 (  )

A:在利用肝组织块制备细胞悬液时,可用胰蛋白酶或胶原蛋白酶处理

B:动物细胞培养应在含5%CO2的恒温培养箱中进行,CO2的作用是刺激细胞呼吸

C:为了防止动物细胞培养过程中细菌的污染,可向培养液中加入适量的抗生素

D:在合成培养基中,通常需加入血清、血浆等天然成分

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B

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Do you like spicy food?

    What's your opinion on spicy food? Some people cannot handle even the smallest amount of chili-red pepper-in their dinner while others can't get enough of it.

    Scientists have long been puzzled by why some people love chili while others loathe it. Plenty of research has been done on the subject, dating as far back as the 1970s. Previous results showed that a love of chili is related to childhood experiences, and cultural influences affect our taste buds too. But the latest study has found that a person's love of spicy food may be linked to his or her personality more than anything else, CBC News reported.

    'We have always assumed that liking drives intake-we eat what we like and we like what we eat. But no one has actually directly bothered to connect these personality traits with intake of chili peppers,' said Professor John Hayes from Pennsylvania State University, who led the study.

    But before you look at the study, you should first know that “spicy” is not a taste, unlike sour, sweet, bitter and salty. It is, in fact, a burning sensation that you feel on the surface of your tongue. This got scientists thinking that maybe a love of spicy food is brought about by people's longing for thrill, something they usually get from watching action movies or riding a roller coaster.

    In the study, 97 participants, both male and female, were asked to fill out questionnaires about certain traits of their personality, for example, whether they like new experiences or tend to avoid risks. They were then given a glass of water with capsaicin, the plant chemical that makes a chili burn, mixed into it.

    By comparing the answers to the questionnaire and what participants said they felt about the spicy water, researchers found that those who tended to enjoy action movies or take risks were about six times more likely to enjoy the spicy water.

    Interestingly, we used to believe that the reason some people can withstand spicy food is that their tongues have become less sensitive to it. However, this latest study has found otherwise. “It's not that it doesn't burn as badly, it's that you actually learn to like the burn,” Hayes explained.