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  • 单元格周期规范 - 高级

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    What would happen if this cycle proceeds at will?
    ::如果这一周期随意进行,会发生什么情况?

    Your may grow and divide without performing their necessary functions, or without fully replicating their , or without copying their . Probably not much good could come of that. So the needs to be highly regulated and tightly controlled. And it is.
    ::您的成长和分裂可能没有履行其必要的职能,或者没有完全复制,或者没有复制。也许没有多大好处。因此,需要高度监管和严格控制。而且确实如此。

    Control of the Cell Cycle
    ::控制细胞循环

    How does the cell know when to divide? How does the cell know when to replicate its DNA? How does the cell know when to proceed into or cytokinesis ? The answers to these questions have to do with the control of the cell cycle. But how is the cell cycle controlled or regulated? Regulation of the cell cycle involves processes crucial to the survival of a cell. These include the detection and repair of damage to DNA, as well as the prevention of uncontrolled . Uncontrolled cell division can be deadly to an organism ; its prevention is critical for survival.
    ::细胞如何知道何时可以分离? 细胞如何知道何时可以复制DNA? 细胞如何知道何时可以复制DNA? 细胞如何知道何时可以进入或细胞基内斯? 这些问题的答案与细胞循环的控制有关。 但是,细胞循环是如何控制或调节的? 细胞循环的监管涉及对细胞生存至关重要的过程,其中包括DNA损害的检测和修复,以及不受控制的细胞分裂的预防。不受控制的细胞分裂对一个有机体可能是致命的;它的预防对于生存至关重要。

    Cyclins and Kinases
    ::赛克林和基纳西斯

    The cell cycle is controlled by a number of protein-controlled feedback processes. Two types of involved in the control of the cell cycle are kinases and cyclins . Cyclins activate kinases by binding to them, specifically they activate cyclin-dependent kinases (CDK) . Cyclins comprise a group of proteins that are rapidly produced at key stages in the cell cycle. Once activated by a cyclin, CDK are that activate or inactivate other target molecules through phosphorylation. It is this precise regulation of proteins that triggers advancement through the cell cycle. Leland H. Hartwell, R. Timothy Hunt, and Paul M. Nurse won the 2001 in Physiology or Medicine for their discovery of these critical proteins.
    ::细胞循环受若干蛋白质控制的反馈程序控制,控制细胞循环的有两种类型,即动脉和环环环; 赛克林斯通过约束来激活动脉,具体地说就是激活依赖环球的动脉(CDK); 赛克林是一组在细胞循环的关键阶段迅速生产的蛋白质。 一旦被环球激活,CDK就是通过磷酸化来激活或停止其他目标分子的。正是这种对蛋白质的精确规定触发了细胞循环的发展。 Leland H. Hhartwell、R.Timothy Hunt和Paul M. 护士为发现这些关键蛋白质在生理学或医学领域赢得了2001年的胜利。

    Cyclin-Dependent Kinases
    ::Cyclin- 依赖性基纳西

    Cyclin-dependent kinases (CDKs) are a family of protein kinases first discovered for their role in regulating the cell cycle. CDKs are present in all eukaryotes , and their regulatory function in the cell cycle has been evolutionarily conserved. CDKs are small proteins with little more than the kinase . A CDK binds to a cyclin regulatory protein , activating the protein; without binding to cyclin, the CDK has little kinase activity. CDKs phosphorylate their substrates on serines and threonines, so they are serine-threonine kinases. CDKs are also involved in regulating , mRNA processing, and the differentiation of nerve cells.
    ::Cyclin依赖的直系骨骼(CDKs)是一个由蛋白质直系细胞循环调节作用首次发现的直系骨骼细胞组成的家族。CDKs存在于所有eukaryotes中,其细胞循环的调节功能也得到了逐步保护。CDKs是小蛋白质,仅次于直系骨骼。CDK与环状的调节蛋白结合,激活蛋白质;不与环状蛋白结合,CDK没有细微的直系细胞活性。CDKs磷化其子细胞在沙丁鱼和硫酮上的分泌,因此它们是麻素直系骨质。CDKs也参与了神经细胞的调节、 mRNA处理和区分。

    Checkpoints
    ::检查站

    The cell cycle has key checkpoints. When the cell receives key signals or information via feedback regulation , the cell can begin the next phase of the cell cycle. The cell can also receive signals that delay passage to the next phase of the cell cycle. These signals allow the cell to complete the previous phase before moving forward. Three key checkpoints are the cell growth (G 1 ) checkpoint, the G 2 checkpoint, and the mitosis checkpoint. The DNA synthesis checkpoint is another checkpoint.
    ::细胞循环有关键的检查站。当细胞通过反馈条例收到关键信号或信息时,细胞可以开始细胞循环的下一阶段。细胞还可以收到延迟进入细胞循环下一阶段的信号。这些信号允许细胞在前进前完成前一个阶段。三个关键检查站是细胞生长检查站(G1)、G2检查站和骨质疏松检查站。DNA合成检查站是另一个检查站。

    The cell growth (G 1 ) checkpoint allows the cell to proceed into the S phase of the cell cycle and continue on to divide, or delay division, or enter a resting stage. The cell spends most of the cycle in the G 1 phase. G 1 is where the cell carries out its main functions. If the cell has performed its functions and has grown to significant size to be divided in half, key proteins will signal the cell to proceed to the S phase and stimulate DNA replication to begin. If the cells are not to divide, such as some muscle and nerve cells, the cell will stop at this checkpoint and move into a resting phase, G 0 . Some cells may stay in this resting period permanently, never dividing.
    ::细胞生长( G1 ) 检查站允许细胞进入细胞循环的S 阶段,并继续分裂或推迟分裂,或进入休息阶段。细胞在G1 阶段度过大部分周期。G1 是细胞发挥主要功能的地方。如果细胞已经发挥功能,并且已经大到两半,关键蛋白质将信号细胞进入S 阶段,并刺激DNA复制开始。如果细胞不进行分离,例如一些肌肉和神经细胞,细胞将停止在这个检查点,进入休息阶段。有些细胞可能永远停留在这个休息期,永远不分开。

    The second checkpoint is located at the end of G 2 phase. Passing this checkpoint triggers the start of the mitosis. If this checkpoint is passed, the cell initiates the many molecular processes that signal the beginning of mitosis.
    ::第二个检查站位于G2级末端。 通过这个检查站会触发分裂症的开始。如果通过这个检查站,细胞会启动许多分子过程,以示分裂症的开始。

    The mitosis checkpoint determines the end of one cycle and the beginning of the next. This checkpoint occurs at the point in metaphase where all the should have aligned at the metaphase plate. This checkpoint signals the beginning of anaphase , allowing the cell to complete mitosis and prepare for the beginning of G 1 of the next cell cycle.
    ::分裂症检查站确定一个周期的结束和下一个周期的开始。 该检查站位于元阶段点,所有元阶段的板块都应对齐。 该检查站标志着阶段的开始,使细胞能够完成分裂症并准备下一个细胞周期的G1的开始。

    The DNA synthesis (S) checkpoint determines if the cell is ready for mitosis. enzymes check the replicated DNA at this point. If the checkpoint is passed, the many molecular mechanisms and processes needed for mitosis will begin.
    ::DNA合成(S)检查站确定细胞是否准备进行分裂。 酶在此点检查复制的DNA。 如果检查站通过, 将启动许多分子机制以及分裂所需的过程 。

    lesson content

    Checkpoints in the eukaryotic cell cycle ensure that the cell is ready to proceed before it moves on to the next phase of the cycle. In this diagram the G 1 , S, and M checkpoints are shown.
    ::eukaryoy细胞循环的检查站确保细胞在进入周期下一阶段之前准备就绪。图中显示G1、S和M检查站。

    Regulation Summary
    State Name Abbreviation Checkpoint

    Quiescent
    ::双月

    Senescent
    ::白月

    		Resting phase G 0 phase
    Interphase

    1 st growth phase
    ::第一增长阶段

    Synthesis phase
    ::综合阶段

    2 nd growth phase
    ::第二增长阶段

    G 1
    ::G1 1 G1

    S
    ::S S 级

    G 2
    ::G2 日内瓦2

    The G 1 checkpoint ensures that the cell has completed its homeostatic functions and is ready for DNA synthesis.
    ::G1检查站确保该囚室已完成主机功能,并准备进行DNA合成。

    The S phase checkpoint ensures that DNA replication is complete.
    ::S阶段检查站确保DNA复制工作完成。

    The G 2 checkpoint ensures that the cell is ready to enter the M (mitosis) phase and divide.
    ::G2检查站确保该牢房准备进入M(分裂)阶段并进行分割。

    Cell division Mitosis M A checkpoint in the middle of mitosis (at metaphase) ensures that the cell is ready to complete cell division.

    Summary
    ::摘要

    • The cell cycle is controlled through feedback mechanisms involving cyclin and CDK proteins.
      ::细胞循环通过涉及环环和CDK蛋白质的反馈机制加以控制。
    • Three important checkpoints are the G 1 , G 2 , and M phase checkpoints.
      ::三个重要的检查站是G1、G2和M级检查站。

    Review
    ::回顾

    1. What are cyclin-dependent kinases? What is their role?
      ::骑自行车的狂欢是什么?他们扮演什么角色?
    2. What is a cell cycle checkpoint?
      ::什么是细胞循环检查站?
    3. What are the important cell cycle checkpoints?
      ::什么是重要的细胞循环检查站?
    4. Describe the role of the cell cycle checkpoints.
      ::说明细胞循环检查站的作用。