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G蛋白偶联受体调控着细胞对激素、神经递质的大部分应答.如图表示促甲状腺激素与靶细胞膜内侧的G蛋白偶联受体结合,活化G蛋白,进而引起细胞内一系列代谢变化的过程.请回答:

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    Nobody is sure where and when the expression “apple-pie order” began. Some say that Scottish and English writers used the expression a long time ago. Others say it was first used in the northeastern American states known as New England. The housewives of New England cut their apples in even slices. Then they filled pie pans with them in an organized way, row upon row. As one writer said, the women of New England loved to have everything in its place. This perhaps explains why it generally is believed that the expression “apple-pie order” began in New England.

    Another old expression, “apple of discord”, comes from ancient mythology(神话), however. The myth says that all the gods and goddesses were sitting around the table to celebrate the marriage of Thetis and Peleus. One of the goddesses-Discord was a troublemaker. She threw away a golden apple on the table to be given as a prize to the most beautiful goddess.

    At one time, the tomato was called a love apple. That was a mistake. This is how the mistake happened: In the sixteenth century, Spain brought the tomato from South America after Spanish explorers had landed there. Spain then sold the tomato to Morocco. Italian traders carried it on to Italy. The Italian name for the tomato was “pomo di Moro” meant “d'amour” -the French word for love. And so “pomo di Moro” became the apple of love.

    People believe many things about the apple. One belief is that it has great powers of keeping people healthy. A very common expression is "an apple a day keeps the doctor away."

    Another belief is based on fact. The expression is "one rotten apple spoils the barrel." When an apple begins to go bad, it ruins all the other apples around it in the container. The expression has come to mean that one bad person in a group can cause everyone to act bad.