termination codon

简明释义

终止密码子

英英释义

例句

1.In eukaryotic cells, the termination codon 终止密码子 is recognized by release factors that promote the disassembly of the ribosome.

在真核细胞中，终止密码子 termination codon 被释放因子识别，促进核糖体的解离。

2.Mutations in the DNA sequence can create a premature termination codon 终止密码子, leading to truncated proteins.

DNA序列中的突变可能会产生一个过早的终止密码子 termination codon，导致蛋白质的截断。

3.During protein synthesis, the ribosome recognizes the termination codon 终止密码子, signaling the end of translation.

在蛋白质合成过程中，核糖体识别到终止密码子 termination codon，标志着翻译的结束。

4.The presence of a termination codon 终止密码子 in the mRNA is crucial for proper gene expression.

mRNA中存在的终止密码子 termination codon 对于基因表达的正确性至关重要。

5.Researchers often study the effects of various termination codons 终止密码子 on protein function.

研究人员常常研究不同的终止密码子 termination codon 对蛋白质功能的影响。

作文

In the realm of molecular biology, understanding the mechanisms of protein synthesis is crucial for comprehending how genes express themselves in living organisms. One essential component of this process is the concept of a termination codon, which plays a pivotal role in signaling the end of protein synthesis. The termination codon is a specific sequence of nucleotides in messenger RNA (mRNA) that does not code for any amino acid but instead signals to the ribosome that the protein chain is complete. This codon is fundamental for ensuring that proteins are synthesized correctly and efficiently.Protein synthesis occurs in two main stages: transcription and translation. During transcription, a segment of DNA is transcribed into mRNA, which carries the genetic information needed for protein production. Once the mRNA is formed, it undergoes processing and then moves to the ribosome, where translation takes place. Here, the ribosome reads the mRNA sequence in sets of three nucleotides, known as codons, each of which corresponds to a specific amino acid. However, when the ribosome encounters a termination codon, it recognizes that it must stop adding amino acids to the growing polypeptide chain.There are three primary types of termination codons: UAA, UAG, and UGA. Each of these sequences serves the same purpose but does not correspond to any amino acid during the translation process. Instead, they act as signals for the release factors to bind to the ribosome. This binding prompts the ribosome to release the newly synthesized polypeptide, which then folds into its functional form. Without the presence of a termination codon, the ribosome would continue to add amino acids indefinitely, leading to nonfunctional proteins and potentially harmful consequences for the cell.The importance of the termination codon extends beyond just the completion of protein synthesis; it also plays a role in regulating gene expression. By controlling when and how proteins are made, cells can respond to environmental changes and maintain homeostasis. For instance, if a cell requires a certain protein to combat stress or infection, the timely recognition of the termination codon ensures that the protein is produced in adequate amounts and at the right time.Moreover, mutations in the termination codon can lead to significant biological implications. A mutation that converts a normal codon into a termination codon can result in premature termination of protein synthesis, producing truncated proteins that may lack essential functions. Conversely, a mutation that prevents the formation of a termination codon can cause proteins to be elongated unnecessarily, potentially leading to toxic effects within the cell.In conclusion, the termination codon is a vital element in the process of protein synthesis. It ensures that proteins are accurately and efficiently produced, allowing cells to function properly. Understanding the role of the termination codon in molecular biology not only enhances our knowledge of genetics but also opens avenues for research in medical science, particularly in understanding genetic disorders and developing targeted therapies. As we delve deeper into the complexities of life at the molecular level, the significance of the termination codon continues to unfold, illustrating the intricate dance of life governed by the language of nucleotides.

在分子生物学领域，理解蛋白质合成的机制对于理解基因如何在生物体中表达至关重要。这个过程中一个重要的组成部分是终止密码子的概念，它在信号传递方面发挥着关键作用，标志着蛋白质合成的结束。终止密码子是在信使RNA（mRNA）中的特定核苷酸序列，它不编码任何氨基酸，而是向核糖体发出信号，表示蛋白质链已经完成。这个密码子对于确保蛋白质的正确和高效合成至关重要。蛋白质合成发生在两个主要阶段：转录和翻译。在转录过程中，DNA的一段被转录成mRNA，后者携带着合成蛋白质所需的遗传信息。一旦mRNA形成，就会经历处理，然后移动到核糖体，在那里进行翻译。在这里，核糖体以三核苷酸为单位读取mRNA序列，这些单位称为密码子，每个密码子对应一个特定的氨基酸。然而，当核糖体遇到终止密码子时，它会意识到必须停止向不断增长的多肽链添加氨基酸。终止密码子有三种主要类型：UAA、UAG和UGA。每种序列都起到相同的作用，但在翻译过程中不对应任何氨基酸。相反，它们作为释放因子与核糖体结合的信号。这种结合促使核糖体释放新合成的多肽，然后它会折叠成其功能形式。如果没有终止密码子的存在，核糖体将继续无限期地添加氨基酸，从而导致非功能性蛋白质的产生，并可能对细胞造成有害后果。终止密码子的重要性不仅限于蛋白质合成的完成；它还在调节基因表达中发挥作用。通过控制何时以及如何制造蛋白质，细胞能够对环境变化作出反应并维持稳态。例如，如果细胞需要某种蛋白质来抵抗压力或感染，及时识别终止密码子可以确保蛋白质在适当的量和时间内被生产出来。此外，终止密码子的突变可能导致重大的生物学影响。将正常密码子转换为终止密码子的突变可能导致蛋白质合成的过早终止，产生缺失必要功能的截短蛋白。相反，阻止终止密码子形成的突变可能导致蛋白质不必要地延长，从而可能在细胞内引发毒性效应。总之，终止密码子是蛋白质合成过程中一个至关重要的元素。它确保蛋白质的准确和高效生产，使细胞能够正常运作。理解终止密码子在分子生物学中的作用，不仅增强了我们对遗传学的认识，还为医学科学研究开辟了新的途径，特别是在理解遗传疾病和开发靶向疗法方面。随着我们深入探索生命在分子层面的复杂性，终止密码子的重要性不断显现，展示了由核苷酸语言主导的生命复杂舞蹈。