雅思阅读真题（Part 3）
味蕾地理分布：舌头如何尝出酸甜苦咸鲜
本篇也叫：味蕾地图、舌头味觉地图、味觉地图、味蕾分布图、舌头味蕾、味觉感受器
Part 3 · 考频：中频 · 最近考试：2018.8.2
本篇为雅思阅读真题（Part 3）《The geography of taste bud》，共 14 题，2018.8.2雅思考试真题回忆，页面提供完整原文、题目、答案与解析，并支持在线机考模式免费练习。本页同时提供 Markdown 版本 供 AI 助手与搜索引擎直接读取。
文章讲述科学家绘制人类舌头味觉地图，发现酸味感受器并推翻旧‘味觉地图’误区。味蕾是洋葱状细胞束，帮助祖先辨别毒物与能量来源。舌头能尝出甜、酸、苦、咸、鲜五味，酸味来自酸性化合物，可警示腐败食物。日本梅干、酸奶油、德式酸菜等酸味食品受现代人喜爱。早期‘舌头分区图’源于误译，现已过时。
Scientific researchers mapping the geography of the human tongue have finally succeeded in locating and identifying the sensors for sour tastes
A
Scientists have long known that the surface of the tongue is covered with taste buds: onion- shaped bundles of cells that stand guard for the digestive system. Long before our modern world of supermarkets and restaurants, taste buds served as a crucial tool to maintain the daily existence of our ancestors. The bitter flavour of a wild almond told a prehistoric human foraging in African forests that the nut was poisonous, and they should spit it out. A sweet fruit, though, was safe to consume, and full of energy from carbohydrates. The presence of lions and other man-eating predators also added urgency to meal choices. 'If the thing didn't taste good, you might decide it's not worth it to be out in the open and at risk,' says Steve Miller, a taste researcher at the University of Maryland School of Medicine.
B
Much of what we 'taste' in everyday life is actually the work of our nose. The tongue can distinguish only five basic flavour sensations - sweet, sour, bitter, salt and umami, the 'savoury' taste of meat and cheese which indicates protein. Sour taste comes from acidic compounds, and, like bitter taste, it can be a sign to leave decomposing meat or vegetables. Unpleasant tartness in unripe fruits comes from too much citric acid. This is how a tree or shrub keeps hungry diners at bay until its seeds are mature enough to travel - via the diner's digestive system - to a new home.
Unlike animals, humans have acquired a taste for tartness. In the case of the Japanese pickle called 'umeboshi', the plums are harvested when still green and sour, before the tree fills them with sugar and turns them into a tantalising snack for birds and animals. Sour cream, yoghurt, lemonade, gorgonzola cheese, the German fermented cabbage 'sauerkraut' and other tart treats are eaten every day by millions of people.
C
Only a decade ago, popular myth held that separate areas of the tongue were responsible for each taste. Referred to as the 'mouth map', the concept probably originated with a German text mistranslated into English at the beginning of the 20th century. As recently as 1996, 'mouth map' diagrams still appeared in university neuroscience textbooks.
D
By the late 1990s, however, scientists had learned enough about molecular biology to turn their attention seriously to taste. They had discovered that thousands of taste buds cover the tongue, each containing 50 to 100 taste cells. Each cell has two poles: one end covered with taste receptors projecting from the tongue's surface, and one end inside the tongue that connects to the brain via nerves. When a person bites into a lemon, acidic molecules from the food bump into acid-sensitive taste receptors, activating a taste cell, which sends a 'sour' message to the brain.
E
The details of this process were long a matter of debate. In line with the 'mouth map' concept, some scientists believed that the taste buds in different areas of the tongue were filled with cells of only one type: the tip with sweet-sensing cells, the back with bitter-sensing cells, and so on. Others were not convinced and further suggested the location of cells was not an issue because each cell could sense all five tastes. However, no one had identified any of the taste receptors, so which cells responded to which tastes was unknown. The recent discovery of the sour-taste receptor is a major step forward. Researchers found that the receptor is a specialized protein channel in the membrane of the taste cell. When acid from a food, such as the citric acid in a lemon, enters the pore of this channel, it triggers a change in the cell's electrical charge, ultimately leading to a signal being sent to the brain.
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答案：TRUE
原文定位：Long before our modern world of supermarkets and restaurants, taste buds served as a crucial tool to maintain the daily existence of our ancestors
同义替换：「in the past」↔「long before our modern world」，「more critical for survival」↔「crucial tool to maintain the daily existence」
答案：FALSE
原文定位：The tongue can distinguish only five basic flavour sensations - sweet, sour, bitter, salt and umami, the 'savoury' taste of meat and cheese which indicates protein
同义替换：「identify」↔「indicates」，「sour taste」↔「umami」
答案：TRUE
原文定位：Unpleasant tartness in unripe fruits comes from too much citric acid. This is how a tree or shrub keeps hungry diners at bay until its seeds are mature enough to travel
同义替换：「plants」↔「tree or shrub」，「sour-tasting acid」↔「tartness」，「protect their seeds」↔「keeps hungry diners at bay until its seeds are mature」
答案：NOT GIVEN
原文定位：Unlike animals, humans have acquired a taste for tartness
答案：FALSE
原文定位：The concept probably originated with a German text mistranslated into English at the beginning of the 20th century
同义替换：「accurate」↔「mistranslated」
答案：taste receptors
原文定位：one end covered with taste receptors projecting from the tongue's surface;acidic molecules from the food bump into acid;sensitive taste receptors;
同义替换：「interact with」↔「bump into」，「on the tongue」↔「projecting from the tongue's surface」
答案：brain
原文定位：one end inside the tongue that connects to the brain via nerves
答案：acidic
原文定位：When a person bites into a lemon, acidic molecules from the food bump into acid-sensitive taste receptors, activating a taste cell, which sends a 'sour' message to the brain
同义替换：「for a sour taste」↔「sour message」，「activate」↔「bump into」
答案：area
原文定位：some scientists believed that the taste buds in different areas of the tongue were filled with cells of only one type
同义替换：「each」↔「different」
答案：location
原文定位：Others were not convinced and further suggested the location of cells was not an issue because each cell could sense all five tastes
同义替换：「unimportant」↔「not an issue」，「every single」↔「each」，「detect」↔「sense」
答案：B
原文定位：Sour cream, yoghurt, lemonade, gorgonzola cheese, the German fermented cabbage 'sauerkraut' and other tart treats are eaten every day by millions of people
同义替换：「consumed」↔「eaten」
答案：C
原文定位：Referred to as the 'mouth map', the concept probably originated with a German text mistranslated into English at the beginning of the 20th century. As recently as 1996, 'mouth map' diagrams still appeared in university neuroscience textbooks
同义替换：「the reason why」↔「originated with」，「continued」↔「still」，「be taught」↔「appeared in university textbooks」
答案：A
原文定位：The presence of lions and other man-eating predators also added urgency to meal choices. 'If the thing didn't taste good, you might decide it's not worth it to be out in the open and at risk,' says Steve Miller
同义替换：「constant danger」↔「man-eating predators」，「ancestors」↔「prehistoric human」，「faced while eating」↔「meal choices」
答案：E
原文定位：The recent discovery of the sour-taste receptor is a major step forward. Researchers found that the receptor is a specialized protein channel in the membrane of the taste cell;ultimately leading to a signal being sent to the brain
同义替换：「breakthrough」↔「discovery」，「identified」↔「found」，「sensing sourness」↔「sour-taste receptor」