base substitution

简明释义

盐基替换;

英英释义

例句

1.A base substitution 碱基替换 can be silent, meaning it does not change the protein produced.

一个碱基替换可以是沉默的，这意味着它不会改变所产生的蛋白质。

2.The base substitution 碱基替换 occurred during DNA replication, causing an error in the genetic code.

在DNA复制过程中发生了碱基替换，导致遗传密码中的错误。

3.Some diseases are caused by a single base substitution 碱基替换 in a critical gene.

一些疾病是由关键基因中的单个碱基替换引起的。

4.Researchers found that the base substitution 碱基替换 in the DNA sequence was responsible for the genetic mutation.

研究人员发现，DNA序列中的碱基替换是导致遗传突变的原因。

5.In molecular biology, a base substitution 碱基替换 can lead to a different amino acid being produced.

在分子生物学中，碱基替换可能导致产生不同的氨基酸。

作文

In the realm of molecular biology, the concept of base substitution plays a crucial role in understanding genetic mutations and their implications. A base substitution refers to a type of mutation where one nucleotide base is replaced by another in the DNA sequence. This seemingly simple change can lead to significant consequences for an organism, influencing everything from physical traits to susceptibility to diseases. In this essay, I will explore the mechanisms behind base substitution, its effects on protein synthesis, and its relevance in evolutionary biology.To begin with, it is essential to understand how base substitution occurs at the molecular level. DNA is composed of a sequence of nucleotides, which include adenine (A), thymine (T), cytosine (C), and guanine (G). During DNA replication or due to environmental factors, such as radiation or chemicals, a nucleotide may be incorrectly paired or replaced. For instance, if an adenine (A) is substituted with a cytosine (C), this alteration is classified as a base substitution. There are two primary types of base substitution: transitions and transversions. A transition involves substituting a purine for another purine (A ↔ G) or a pyrimidine for another pyrimidine (C ↔ T), while a transversion involves substituting a purine for a pyrimidine or vice versa.The impact of base substitution on protein synthesis is profound. The genetic code is read in triplets, known as codons, each of which corresponds to a specific amino acid. When a base substitution occurs, it may lead to a silent mutation, where the amino acid remains unchanged, or a missense mutation, where the amino acid is altered. In some cases, it can even result in a nonsense mutation, leading to a premature stop codon. These changes can affect the structure and function of proteins, potentially resulting in diseases such as sickle cell anemia, which is caused by a single base substitution in the hemoglobin gene.Moreover, base substitution has significant implications in the field of evolutionary biology. Genetic variations, including those caused by base substitution, are the raw material for evolution. When mutations occur, they can confer advantages or disadvantages to an organism's survival and reproduction. Over time, beneficial mutations may become more common in a population through natural selection, while harmful mutations may be eliminated. This process highlights the dynamic nature of genomes and how base substitution contributes to the diversity of life on Earth.In conclusion, the study of base substitution is pivotal for understanding the complexities of genetics and evolution. This mutation type, although it may seem minor, can have far-reaching effects on an organism's phenotype and fitness. As researchers continue to unravel the intricacies of DNA and its mutations, the importance of base substitution in both health and disease will undoubtedly remain a key focus in the field of molecular biology. By comprehending how these mutations arise and their consequences, we can gain deeper insights into the mechanisms of life and the processes that drive evolution.

在分子生物学领域，碱基替换的概念在理解基因突变及其影响方面起着至关重要的作用。碱基替换是指一种突变类型，其中DNA序列中的一个核苷酸碱基被另一个碱基替换。这种看似简单的变化可能会对生物体产生重大影响，影响从身体特征到疾病易感性的一切。在这篇文章中，我将探讨碱基替换背后的机制、其对蛋白质合成的影响以及其在进化生物学中的相关性。首先，理解碱基替换在分子水平上如何发生是至关重要的。DNA由一系列核苷酸组成，包括腺嘌呤(A)、胸腺嘧啶(T)、胞嘧啶(C)和鸟嘌呤(G)。在DNA复制期间或由于环境因素（例如辐射或化学物质），一个核苷酸可能会被错误配对或替换。例如，如果腺嘌呤(A)被胞嘧啶(C)替换，这种改变被归类为碱基替换。碱基替换主要有两种类型：转换和转移。转换涉及将一种嘌呤替换为另一种嘌呤(A↔G)或将一种嘧啶替换为另一种嘧啶(C↔T)，而转移则涉及将一种嘌呤替换为嘧啶或反之。碱基替换对蛋白质合成的影响是深远的。遗传密码以三联体的形式读取，称为密码子，每个密码子对应特定的氨基酸。当发生碱基替换时，它可能导致无义突变，即氨基酸保持不变，或错义突变，即氨基酸被改变。在某些情况下，它甚至可能导致无义突变，导致提前的终止密码子。这些变化可能会影响蛋白质的结构和功能，可能导致疾病，例如镰状细胞贫血，这种疾病是由血红蛋白基因中的单个碱基替换引起的。此外，碱基替换在进化生物学领域具有重要意义。遗传变异，包括由碱基替换引起的变异，是进化的原材料。当突变发生时，它们可能会给生物体的生存和繁殖带来优势或劣势。随着时间的推移，有利的突变可能通过自然选择在种群中变得更为普遍，而有害的突变可能会被消除。这个过程突显了基因组的动态特性，以及碱基替换如何促进地球上生命的多样性。总之，研究碱基替换对于理解遗传学和进化的复杂性至关重要。这种突变类型虽然看似微不足道，但对生物体的表型和适应性可能产生深远影响。随着研究人员继续揭示DNA及其突变的复杂性，碱基替换在健康和疾病中的重要性无疑将继续成为分子生物学领域的关键焦点。通过理解这些突变如何产生及其后果，我们可以深入了解生命的机制和推动进化的过程。