18 Food and Nutrition-Mid

Food and Nutrition Written by Katherine Follett

《食物与营养》凯瑟琳·福莱特著

What Needs Food? All living things need energy. They need it to live, to do all the things they do each day, and to stay healthy. Living things get this energy from food. In this book, you will learn about two very important processes: how living things get food and how living things use food for energy. Before reading on, think about how plants get food and how they use it for energy.

什么需要食物?所有生物都需要能量。 他们需要它来生活，做他们每天要做的所有事情，并保持健康。 生物从食物中获取能量。 在这本书中，你将了解到两个非常重要的过程:生物如何获取食物，以及生物如何利用食物作为能量。 在继续阅读之前，想想植物是如何获取食物的，以及它们是如何利用食物作为能量的。

How Do Plants Get Food? Plants and animals get the energy they need in different ways. Animals get energy by eating food. But plants do not eat. Plants make their own food in a process called photosynthesis. During photosynthesis, plants make a simple kind of sugar. This becomes their food source. You may think that plants get their food from the soil, but they don't Green plants contain chlorophyll, which absorbs the sunlight plants use to make sugar. Plants also use a gas called carbon dioxide, which is found in the air. The carbon dioxide gets absorbed through tiny holes that are mainly found on the bottom of a plant's leaves. Plants make food using sunlight, carbon dioxide, and water. It is true that soil does not provide plants with food. But soil does supply plants with water and minerals, which are both absorbed through the roots. Water and minerals are important during photosynthesis. Study the diagram of a plant on page 6. It explains the steps of photosynthesis that take place inside green plants.

植物如何获取食物?植物和动物以不同的方式获取所需的能量。 动物通过进食获得能量。 但是植物不吃东西。植物通过光合作用产生自己的食物。 在光合作用中，植物会产生一种简单的糖。 这就成了它们的食物来源。 你可能认为植物从土壤中获取食物，但事实并非如此。绿色植物含有叶绿素，它能吸收植物用来制造糖的阳光。 植物也利用空气中存在的一种叫做二氧化碳的气体。 二氧化碳通过植物叶子底部的小孔被吸收。 植物利用阳光、二氧化碳和水制造食物。 的确，土壤不能为植物提供食物。 但土壤确实为植物提供了水和矿物质，这两者都是通过根系吸收的。 水和矿物质在光合作用中很重要。 学习第6页上的植物图。 它解释了绿色植物内部发生光合作用的步骤。

Photosynthesis in Green Plants 1 Roots absorb water and minerals. The plant transports the water to the plant's cells. 2 The cells contain a green pigment called chlorophyll Chlorophyll. captures the Sun's energy. 3 The plant takes in carbon dioxide from the air through tiny holes on the bottoms of its leaves. 4 The leaf cells use the Sun's energy to break down the carbon dioxide and water. They convert the chemicals into a simple sugar, which is the plant's food. 5 The plant uses some of the sugar it makes. It stores the rest in its leaves, stem, roots, and other parts. 6 Oxygen gas is given off as a waste product when sugar is made. The leaves release the oxygen back into the air through the tiny holes.

绿色植物的光合作用1根吸收水分和矿物质。 植物将水输送到植物细胞中。 细胞中含有一种叫做叶绿素的绿色色素。 吸收太阳的能量 这种植物通过叶子底部的小孔从空气中吸收二氧化碳。 叶子细胞利用太阳的能量分解二氧化碳和水。 它们将化学物质转化为单糖，这是植物的食物。 5 .这种植物利用自己生产的一些糖。 它将剩余的水分储存在叶子、茎、根和其他部位。 在制糖的过程中，氧气作为废物释放出来。 树叶通过小孔将氧气释放回空气中。

In the formula below, the left side explains what plants use during photosynthesis. The right side explains what plants produce during photosynthesis. The arrow is like an equal sign. How Do Plants Use Food for Energy? After photosynthesis, the plant has sugar it can use for energy. Some of that energy remains stored inside the plant's leaves, stem, fruit, roots, and other parts. The plant uses the rest of the energy to grow by making new cells. The plant then breaks down the sugar in a different process, which is called respiration. Respiration is the opposite of photosynthesis. This time, the plant takes in oxygen from the air. The oxygen reacts with the sugar, creating the energy the plant needs in order to live. During respiration, water and carbon dioxide are also produced. They are released back into the air. Plants perform photosynthesis when the Sun is shining. But plants can perform respiration in either the dark or the light. The next formula explains what plants use (on the left) and what they produce (on the right) during respiration.

在下面的公式中，左边解释了植物在光合作用中使用的物质。 右边解释了植物在光合作用中产生什么。 箭头就像一个等号。 植物如何利用食物获取能量? 在光合作用后，植物有糖可用作能量。 其中一些能量储存在植物的叶子、茎、果实、根和其他部位。 植物利用剩余的能量通过制造新细胞来生长。 然后植物通过一种叫做呼吸作用的不同过程来分解糖。 呼吸作用与光合作用相反。 这一次，植物从空气中吸收氧气。 氧气与糖发生反应，产生植物生存所需的能量。 在呼吸过程中，水和二氧化碳也会产生。 它们被释放回空气中。 当阳光照耀时，植物进行光合作用。 但是植物可以在黑暗或光照下进行呼吸作用。 下一个公式解释了植物在呼吸过程中使用什么(左边)和产生什么(右边)。

To review, plants make their own food during photosynthesis. Plants use that food for energy during respiration. Photosynthesis can only happen in the light. Respiration can happen in the dark or the light. All living things use respiration. Plants also use photosynthesis. Use this chart to compare the two processes. PHOTOSYNTHESIS RESPIRATION produces food uses food stores energy releases energy uses water uses sugar (glucose) uses carbon dioxide uses oxygen produces sugar (glucose) produces water vapor produces oxygen produces carbon dioxide occurs in sunlight occurs in the dark or light used mainly by plants used by all living things Try This You can prove that plants give off water vapor during respiration. Seal a bag over a few leaves of a living plant for a few days and see what happens.

回顾一下，植物在光合作用过程中会自己制造食物。 植物在呼吸过程中利用这些食物作为能量。 光合作用只能在光照下进行。 呼吸作用可以在黑暗中发生，也可以在光明中发生。 所有生物都要呼吸。 植物也利用光合作用。 用这个图表来比较这两个过程。 光合作用呼吸作用产生食物使用食物储存能量释放能量使用水使用糖(葡萄糖)使用二氧化碳使用氧气产生糖(葡萄糖)产生水蒸气产生氧气产生二氧化碳发生在阳光下发生在黑暗或光明中主要由植物利用所有生物利用你可以证明植物在呼吸时释放水蒸气。 把一个袋子封在几片活的植物叶子上几天，看看会发生什么。