19 Food and Nutrition-High

Food and Nutrition Written by Barb Davis

《食物与营养》作者:巴布·戴维斯

What Needs Food? All living things, or organisms, need energy in order to live, complete their daily activities, and remain healthy. This energy comes from food. This book explains two life-sustaining processes: how organisms get food and how food goes through changes inside organisms so they can use the food for energy. Before reading on, think about how plants get food and how they turn the food into energy.

什么需要食物?所有生物或有机体都需要能量来维持生命、完成日常活动和保持健康。 这种能量来自食物。 这本书解释了两个维持生命的过程:生物体如何获得食物，以及食物如何在生物体内部发生变化，以便它们可以利用食物作为能量。 在继续阅读之前，想想植物是如何获取食物的，以及它们是如何将食物转化为能量的。

How Do Plants Get Food? As you know, animals get the energy they need to survive by eating many kinds of food found in their environment. But plants don't eat food. Unlike other living things, they have the ability to make their own food. Plants produce food through a chemical process called photosynthesis. During photosynthesis, plants make a simple kind of sugar, called glucose, which becomes their food source. You may have thought that plants get their food from the soil, but this is not the case. Green plants contain chlorophyll, a pigment that absorbs the sunlight used to produce glucose. During photosynthesis, plants also use a gas called carbon dioxide, which is found in the air. The carbon dioxide gets absorbed through tiny holes called stomata, which are mostly found on the underside of a plant's leaves. Although soil does not provide plants with their food, it does supply plants with water and minerals, both of which are absorbed through the roots. Water and minerals aid in the process of photosynthesis. The diagram on page 6 reviews the process of photosynthesis.

植物如何获取食物?如你所知，动物通过吃环境中的各种食物来获取生存所需的能量。 但是植物不吃食物。 与其他生物不同，它们有能力自己制造食物。 植物通过一种叫做光合作用的化学过程生产食物。 在光合作用过程中，植物会产生一种简单的糖，称为葡萄糖，成为它们的食物来源。 你可能认为植物从土壤中获取养分，但事实并非如此。 绿色植物含有叶绿素，这是一种色素，可以吸收阳光产生葡萄糖。 在光合作用过程中，植物也会利用空气中存在的一种叫做二氧化碳的气体。 二氧化碳通过气孔被吸收，气孔主要分布在植物叶片的下方。 虽然土壤不为植物提供食物，但它确实为植物提供了水和矿物质，这两者都是通过根吸收的。 水和矿物质有助于光合作用的过程。 第6页的图表概述了光合作用的过程。

Photosynthesis in Green Plants 1 Roots absorb water and minerals, and transport them to the plant's cells. 2 A green pigment in plant cells, called chlorophyll, captures the Sun's light energy, which the plant turns into chemical energy. 3 Carbon dioxide from air enters the leaf through tiny holes called stomata. 4 The energy from the Sun helps carbon dioxide molecules react with water molecules to make a simple sugar called glucose. 5 The plant uses some of the glucose it makes and stores the rest. 6 Oxygen, a waste product from the food-making process, passes out of the leaf and enters the air.

绿色植物的光合作用1根吸收水分和矿物质，并将它们输送到植物的细胞中。 植物细胞中有一种叫做叶绿素的绿色色素，它能吸收太阳的光能，植物将其转化为化学能。 空气中的二氧化碳通过气孔进入叶子。 来自太阳的能量帮助二氧化碳分子与水分子反应，生成一种叫做葡萄糖的单糖。 5 .植物使用自己制造的一部分葡萄糖，并储存其余的葡萄糖。 氧气是食物制造过程中的废物，它从叶子中排出，进入空气。

Photosynthesis takes place inside the smallest parts of a plant— its cells. Much like bricks in a building, cells join together to make up most living things. The left side of the formula below explains what plants use during photosynthesis. The right side explains what plants produce during photosynthesis. How Do Plants Use Food for Energy? Some of the glucose (sugar) that a plant makes during photosynthesis remains stored in its leaves, fruit, stem, roots, and other parts. To use the rest of the food for energy, the plant must break down the glucose in its cells. This involves a different chemical process, called respiration. During respiration, glucose reacts with oxygen to release energy that plants need to live. Respiration also forms carbon dioxide and water vapor as waste products. These waste products exit the plant through the stomata. The left side of the next formula explains what plants use during respiration. The right side explains what plants produce during respiration.

光合作用发生在植物最小的部分——细胞内。 就像建筑中的砖块一样，细胞结合在一起组成了大多数生物。 下面公式的左边解释了植物在光合作用中使用什么。 右边解释了植物在光合作用中产生什么。 植物如何利用食物获取能量? 植物在光合作用中产生的一些葡萄糖(糖)仍然储存在叶子、果实、茎、根和其他部位。 为了利用剩余的食物作为能量，植物必须在细胞中分解葡萄糖。 这涉及到一种不同的化学过程，称为呼吸作用。 在呼吸过程中，葡萄糖与氧气反应，释放出植物生存所需的能量。 呼吸作用还会形成二氧化碳和水蒸气作为废物。 这些废物通过气孔排出植物。 下一个公式的左边解释了植物在呼吸时使用什么。 右边解释了植物在呼吸时产生的物质。

To review, photosynthesis is how plants make their own food. Respiration is how plants use that food for energy. While photosynthesis occurs in sunlight, respiration can occur in the dark or the light. All organisms use respiration, but plants also use photosynthesis. Use the chart below to compare these two important processes. Photosynthesis Respiration produces food uses food stores energy releases energy uses water uses glucose uses carbon dioxide uses oxygen produces glucose produces water vapor produces oxygen produces carbon dioxide occurs in sunlight occurs in the dark or light used primarily by plants used by all organisms Try This When plants lose water vapor through their leaves, it is called transpiration. To prove that plants give off water, try sealing a few leaves of a living plant in a bag for a few days and watch what happens!

回顾一下，光合作用是植物如何制造自己的食物。 呼吸作用是植物利用食物获取能量的方式。 光合作用在阳光下发生，而呼吸作用可以在黑暗或光照下发生。 所有的生物都需要呼吸作用，但植物也需要光合作用。 使用下面的图表来比较这两个重要的过程。 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葡萄糖使用二氧化碳使用氧气产生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为植物所利用所有生物都使用试试当植物通过叶子失去水蒸气时，这被称为蒸腾作用。 为了证明植物会放水，试着把几片活植物的叶子密封在袋子里几天，看看会发生什么!