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  • lesson content

    In the presence of oxygen. Why?
    ::当着氧气的面 为什么?

    Oxygen is made by trees and other plants during . We know that we need oxygen to live. But why? This oxygen is an essential component for the optimal production of usable energy - which occurs through cellular respiration.
    ::氧是由树木和其他植物制造的。 我们知道我们需要氧来生存。 但是为什么? 氧是最佳生产可用能源的基本成分, 可以通过细胞呼吸产生。

    Cellular Respiration
    ::细胞呼吸

    You know that humans deprived of oxygen for more than a few minutes will quickly become unconscious and die. , also known as respiration , is essential for human life because the body cannot store oxygen for later use as it does food . The mammalian , shown in the Figure  features a diaphragm , trachea , and a thin membrane whose surface area is equivalent to the size of a handball court - all for efficient oxygen intake. Other forms of life employ different types of respiratory organs : and and flaunt gills , spiders, and scorpions develop "book lungs ," and insects use an elaborate network of tubes called tracheae, which open via spiracles , as shown in the Figure  . A constant supply of oxygen gas is clearly important to life. However, do you know why you need oxygen?
    ::你知道,在几分钟以上的时间里没有氧气的人类很快会失去知觉并死亡。 也就是所谓的呼吸,对于人类生命至关重要,因为身体不能储存氧气,供日后使用。图中显示的哺乳动物具有隔膜、气管和薄膜的特征,其表面面积相当于手球球球场的大小,完全是为了高效的氧摄入。其他生命形式则使用不同类型的呼吸器官:以及闪烁的刺绣、蜘蛛和蝎子发展“笔记肺”和昆虫使用一个精密的管网,称为气管网,如图中所示,通过触角打开。氧气的持续供应对于生命来说显然很重要。然而,你知道为什么你需要氧气吗?

    lesson content
    (left) The human respiratory system is only part of the story of respiration. Diaphragm, lungs, and trachea take air deep into the body and provide oxygen gas to the bloodstream. The fate of that oxygen is the story of cellular respiration. (center) Spiracles in this Cluentius Sphinx (Neococytius cluentius) caterpillar connect to a system of internal tubes (tracheae), which carry oxygen throughout the animal's body. (right) Gills in this alpine newt larva, Ichthyosaura alpestris, bring blood close to an extensive surface area so that the newt can absorb dissolved oxygen gas from its watery habitat.

    Many people would answer that oxygen is needed to make carbon dioxide, the gas exhaled or released by each of the respiratory systems listed above. However, CO 2 is a waste product. But a waste product of what?
    ::许多人会回答说,需要氧气来制造二氧化碳,即上述每一种呼吸系统排放或排放的气体。然而,二氧化碳是一种废物产品。但是,什么是废物产品?

    There must be more to this story than just gas exchange with the environment. To begin to appreciate the role of oxygen inside your body, think about when your breathing rate increases: climbing a steep slope, running a race, or skating a shift in a hockey game. Respiration rate correlates with energy use, and that correlation reflects the link between oxygen and energy metabolism . For this reason, the chemical process inside your that consumes oxygen to produce usable energy is known as cellular respiration . During this process, energy is converted from glucose , in the presence of oxygen, into numerous ATP molecules. The glucose, of course, comes from the food you eat. In biological terms, you do not eat because you are hungry, you eat to get energy. Other heterotrophic organisms also acquire glucose from other organisms, whereas autotrophic organisms make their own glucose, mostly through photosynthesis.
    ::这个故事必须不止是气体与环境的交换。 为了开始理解体内氧的作用, 请思考一下呼吸率上升的时间: 攀爬陡峭的斜坡, 赛跑, 或者滑滑曲棍球游戏。 呼吸率与能源使用相关, 而这种关联反映了氧与能源新陈代谢之间的联系。 出于这个原因, 您体内消耗氧气以产生可用能量的化学过程被称为细胞呼吸。 在这个过程中, 能量从甘蔗( 含氧的) 转化成无数ATP分子。 当然, 葡萄糖来自你所吃的食物。 从生物角度讲, 您不吃因为饥饿, 而是吃能量。 其他食血营养生物也从其他生物中获取葡萄糖, 而自食生物则通过光合作自食用自己的葡萄糖。

    Though cellular respiration can occur anaerobically without oxygen, the process is much more efficient under aerobic conditions, in the presence of oxygen. And what exactly is the role of oxygen? Oxygen is the final electron acceptor of the electron transport chain in the final step of cellular respiration. Oxygen combines with electrons and hydrogen ions to produce .
    ::尽管细胞呼吸可以在没有氧气的情况下发生厌氧呼吸,但在有氧条件下,该过程在有氧条件下效率要高得多。氧的作用是什么?氧是细胞呼吸最后一步电子运输链的最后电子接收器。氧与电子和氢离子结合产生。

    Summary
    ::摘要

    • Respiration is the exchange of gases between the body and the outside air.
      ::呼吸是身体和外部空气之间气体的交换。
    • Cellular respiration is the cellular process that transfers chemical energy from glucose to ATP.
      ::细胞呼吸是将化学能量从甘蔗糖转移到ATP的细胞过程。
    • Oxygen is essential to have efficient cellular respiration; most organisms need oxygen for a single purpose: to release energy from food for use by cells.
      ::氧是高效细胞呼吸的关键;大多数生物需要氧,只有一个目的:释放食物能量供细胞使用。

    Review
    ::回顾

    1. Why do nearly all organisms die without a constant supply of oxygen?
      ::为什么几乎所有生物都死而无氧?
    2. Describe the difference between respiration and cellular respiration.
      ::描述呼吸和细胞呼吸之间的区别。
    3. What is the role of oxygen in cellular respiration?
      ::氧气在细胞呼吸中的作用是什么?
    4. Which is most efficient, aerobic respiration or anaerobic respiration?
      ::哪种最有效,有氧呼吸 或厌氧呼吸?