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  • 米托孔德里亚 - 高级

    lesson content

    Sperm cells and muscle cells need lots of energy. What do they have in common?
    ::精密细胞和肌肉细胞需要很多能量 它们有什么共同点?

    They have lots of mitochondria. Mitochondria are called the power plants of the , as these are where most of the cell's energy is produced. Cells that need lots of energy have lots of mitochondria.
    ::它们拥有大量的米托乔翁德里亚。米托昆德里亚被称为该细胞的发电厂,因为这些发电厂是产生细胞大部分能量的地方。需要大量能量的细胞拥有大量的米托孔德里亚。

    The Mitochondria
    ::密托贡德里亚

    A mitochondrion ( mitochondria , plural), is a membrane-enclosed organelle that is found in most eukaryotic cells . Mitochondria are called the "power plants" of the cell because they are the site of . In cellular respiration, the energy from such as glucose , is used to make ATP ( adenosine triphosphate ). ATP is the cell's energy source that is used for such things such as movement and . Some ATP is made in the cytosol of the cell, but most of it is made inside mitochondria. The number of mitochondria in a cell depends on the cell's energy needs. For example, active human muscle cells may have thousands of mitochondria, while less active red blood cells do not have any.
    ::线粒体( 线粒体, 复数) 是一种薄膜封闭的有机体, 存在于大部分的尿液细胞中。 Mitochondria 被称为细胞的“ 电厂” , 因为它们是细胞的所在地 。 在细胞呼吸中, 诸如葡萄糖等能量被用来制造ATP( 乙酰三磷酸酯 ) 。 ATP 是细胞的能量源, 用于诸如运动和 。 一些ATP 是在细胞的细胞溶液中制造的, 但大部分是在米托孔德里亚内部制造的。 细胞中的 mitochondria 数量取决于细胞的能量需求 。 例如, 活性人体肌肉细胞可能有数千 mitochondria , 而不那么活跃的红血细胞则没有 。

    Five Compartments
    ::五节

    As Figure (a) and (b) shows, a mitochondrion has two phospholipids membranes. The smooth outer membrane separates the mitochondrion from the cytosol. The inner membrane has many folds, called cristae . These cristae greatly increase the membrane surface area for integral . Many proteins involved in cellular respiration are embedded in this inner membrane. The greater surface area allows more proteins to be located there, resulting in more cellular respiration reactions, and more ATP synthesis. ATP is produced by the ATP synthase , which is a of the mitochondria inner membrane. The fluid-filled inside of the mitochondrian, called matrix , is where most of the cell's ATP is made.
    ::如图(a)和(b)所示,一离子体有两种磷叶素膜。光滑的外膜将二离子体与细胞质分离。内膜有许多折叠,称为红花。这些角状膜大大增加了集成的膜表面积。许多细胞呼吸中的蛋白都嵌入了这个内膜。更大的表面面积允许在那里找到更多的蛋白,导致更多的细胞呼吸反应,以及更多的ATP合成。ATP合成酶是ATP合成的,该合成酶是米托乔因里亚内膜内膜生成的。Mitochondrian体内的液体填满,称为矩阵,是大部分细胞APP的地方。

    lesson content

    (a): Electron micrograph of a single mitochondrion within which you can see many cristae. Mitochondria range from 1 to 10 μm in size. (b): This model of a mitochondrian shows the organized arrangement of the outer membrane and folded inner membrane with cristae, the inter membrane space, the mitochondrial matrix, and ATP synthase protein complex.
    :伤心a) 单线粒子体的电子显微镜,您可以在其中看到许多圆锥体。米托昆德里亚的大小在1至10微米之间。 (b) :米托乔恩德里亚的这种模型显示了外膜的有组织安排,并折叠了内膜,包括红心膜、膜间空间、米托贡德里亚基体和亚TP合成酶蛋白综合体。

    The mitochondria essentially has five compartments, each with its own function:
    ::缩略语基本上有五个区块,每个区块有自己的功能:

    1. the outer mitochondrial membrane,
      ::外皮薄膜,
    2. the intermembrane space (the space between the outer and inner membranes),
      ::空间(外层空间与内膜之间的空间),
    3. the inner mitochondrial membrane,
      ::内膜膜,
    4. the cristae space (formed by infoldings of the inner membrane), and
      :伤心以内膜的叠叠形式形成的)以及
    5. the matrix (space within the inner membrane).
      ::矩阵(内膜内的空间)。

    The outer membrane contains large numbers of integral proteins called porins . These porins form channels that allow small molecules to freely diffuse across the membrane to the other. The inner mitochondrial membrane is highly impermeable to all molecules. Almost all ions and molecules require special membrane transporters to enter or exit the matrix. ATP synthase , which produces ATP in the matrix, is embedded within this membrane. The cristae greatly expand the surface area of the inner mitochondrial membrane, enhancing the ability of the mitochondria to produce ATP. The matrix contains a highly-concentrated mixture of hundreds of enzymes, the mitochondrial , tRNAs, and several copies of the mitochondrial genome . Of the enzymes, the enzymes are located here.
    ::外膜含有大量称为porin的有机蛋白。 这些porin 形成小分子可以自由散布于膜中, 使小分子可以自由散布于膜中。 内膜膜膜对所有分子都非常密不可分。 几乎所有的离子和分子都需要特殊的膜传输器才能进入或离开矩阵。 生成 ATP 的 ATTP 合成酶嵌入了这个膜中。 胸膜大大扩展了内膜膜中的表层面积, 提高了 mitochondrial 膜中生成 ATP 的能力。 矩阵中含有数以百计的酶、 mitochondrial 、 tRNAs 和多份 MITOondrial 基因组的高度集中的混合物。 在酶中, 酶位于这里 。

    Mitochondria Genome
    ::米托昆德里亚基因组e

    Although most of a cell's is contained in the cell , mitochondria have their own DNA. Mitochondria also have the machinery to manufacture their own RNAs and proteins. The human mitochondrial DNA sequence has 16,569 base pairs encoding 37 total genes : 22 tRNA genes, 2 rRNA genes, and 13 peptide genes. The 13 mitochondrial peptides in humans are integrated into the inner mitochondrial membrane, along with proteins encoded by nuclear genes.
    ::尽管细胞大部分都包含在细胞中,但mitocondria也有自己的DNA。Mitochondria也有制造自己的RNA和蛋白质的机器。人类的线粒体DNA序列有16,569对基对,共编码了37个基因:22个tRNA基因、2个RNA基因和13个peptide基因。人类的13个线粒体和由核基因编码的蛋白被结合到内线粒体膜中。

    Mitochondria are able to reproduce asexually, like , and scientists think that they are descended from prokaryotic organisms . According to the Theory of Endosymbiosis , mitochondria were once free-living that infected other prokaryotic cells . The invading prokaryotes were protected inside the host cell, and in turn the prokaryote supplied extra ATP to its host. Eventually these two cells turned into one eukaryotic cell, as the two organisms evolved so that they could no longer live without each other. Over time, the ancient internal prokaryote turned into an organelle, resulting in a large cell with an internal organelle. By definition, this is an eukaryotic cell.
    ::Mitochondria能够像科学家一样性繁殖,像,科学家们认为他们是来自蛋白质生物的后代。根据《内地生物论》,Mitochondria曾经是感染其他蛋白质细胞的自由生物。入侵的prokayotes在宿主细胞内受到保护,反过来,prokaryte又向宿主提供了额外的ATP。最后,这两个细胞变成了一个eukaryte,因为两个生物在进化后无法再分开生存。随着时间的推移,古老的内部Prokarites变成了一个有机体,导致一个大细胞与一个内部有机体。根据定义,这是一座水晶体细胞。

    Unlike nuclear DNA which is inherited from the father and mother, mitochondrial DNA (mtDNA is most often inherited from mothers. However paternal mtDNA occasionally slips through with . The technical process is still unclear but a study was down using Caenorhabditis elegans that showed double membrane vesicles , called autophagosomes, engulf paternal mitochondria and destroy them.
    ::与从父亲和母亲继承的核DNA不同,米托昆德里DNA(mtDNA通常是从母亲继承的,但父亲的MtDNA偶尔会滑过。 技术过程仍然不清楚,但一项研究正在下降,这项研究使用了双膜乳房,称为自发体,吞没了父亲的mitochondria,并摧毁了它们。

    Since mothers provide the mtDNA and fathers will never pass on a mtDNA, a child shares the same or similar mtDNA sequence as does his/her siblings and mother. This direct inheritance has allowed biologists to track the origin of modern human and to draw maternal lineages.
    ::由于母亲提供MtDNA,父亲也永远不会通过MtDNA,孩子与其兄弟姐妹和母亲的MtDNA序列相同或类似,这种直接继承使生物学家能够追踪现代人类的起源,并绘制母系。

    Unfortunately, maternal mt(DNA)is susceptible to which are a cause of inherited disease, such as breast . Although, it is important to note that most mutations do not lead to defected mtDNA. Heteroplasmy is the presence of a mixture of more than one type of mtDNA. Most people have homoplasmic cells, meaning that their cells contain only normal, undefected mtDNA. However, people with both normal, undefected mtDNA and not normal, defected mtDNA, may inherit mitochondrial diseases. The ultimate condition leading to disease is when the proportion of mutant mtDNA reaches a threshold, after which the cell can no longer cope, resulting in disease. This threshold varies among different tissues and different mutations.
    ::不幸的是,母体Mt(DNA)容易感染,而母体Mt(DNA)是乳房等遗传疾病的一个原因。尽管需要指出的是,大多数突变并不导致叛变 mtDNA。Heteroproplasmy是多种mtDNA的混合体。多数人拥有同族体细胞,这意味着他们的细胞中只有正常的、未受感染的mtDNA。然而,正常的、未受感染的mtDNA,而不是正常的、失常的MtDNA, 可能遗传出三联体疾病。导致疾病的最终条件是变异的MtDNA的比例达到临界值,此后细胞无法再应对,导致疾病。这一临界值在不同组织和不同的突变之间有所不同。

    Summary
    ::摘要

    • Mitochondria are where energy from organic compounds is used to make ATP.
      ::Mitochondria是使用有机化合物的能量制造ATP的地方。
    • Mitochondria have a double-membrane, resulting in five distinct compartments within the mitochondrion. They are:
      • The outer mitochondrial membrane.
        ::外脊髓膜膜
      • The intermembrane space (the space between the outer and inner membranes).
        ::中间空间(外层空间与内膜之间的空间)。
      • The inner mitochondrial membrane.
        ::内膜膜
      • The cristae space (formed by infoldings of the inner membrane).
        ::天花空间(由内膜的叠叠形成)
      • The matrix (space within the inner membrane).
        ::矩阵(内膜内的空间)。

      ::Mitochondria有一个双膜膜,在米托琴德里翁内部形成五个不同的区块。它们是:外线粒子体膜;间缘空间(外线和内膜之间的空间);内线粒子体膜;天花板空间(由内膜的叠叠成)。矩阵(内膜内的空间)。
    • Mitochondria are thought to have evolved from ancient prokaryotic cells.
      ::据认为,米托昆德里亚是从古老的血清细胞进化而来的。
    • Mitochondria are most often maternally inherited.
      ::Mitochondria往往由母亲继承。

    Review
    ::回顾

    1. Identify the reason why mitochondria are called "power plants" of the cell.
      ::找出为什么Mitochondria 被称为细胞的“电厂”的原因。
    2. What are the five compartments of a mitochondria?
      ::什么是米多孔德里亚的五个隔间?
    3. If muscle cells become more active than they usually are, they will grow more mitochondria. Explain why this happens.
      ::如果肌肉细胞变得比通常更活跃, 它们会长出更多的米托孔德里亚。 解释为什么会发生这种情况 。
    4. What determines whether a child inherits a mitochondrial disease?
      ::由何种因素决定儿童是否继承线粒体疾病?