遗传信息在基因中的排列是指四种碱基a、C、G、T的排列。

Heredity information array in genes is the four bases a, C, g, t array.

youdao

它们可以附在胞核嘧啶上，胞核嘧啶是组成基因代码的“字母”的四种碱基数之一，帮助调控转录的过程。

These can attach themselves to cytosine , one of the four chemical bases that form the "letters" of the genetic code.

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其中碳水化合物都是由单糖构成的，蛋白质是由20种氨基酸构成的，核酸是由核糖、脱氧核糖、和5种碱基构成。

Carbohydrates are made of simple sugars, proteins are made up of 20 amino acids, and nucleic acids are compose of oxy - and deoxy - nucleic sugars and 5 base pairs.

youdao

Because it takes three units where there's only four choices at each position to have at least 20 unique combinations.

因为每个位点上仅有四种可能性,只有采用三个碱基一组,才能取得至少二十种不同的组合方式

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There are 64 combinations of three bases and I only need to describe 20, so there's combinations to spare.

三个一组的碱基产生六十四种组合,而我只需对应二十种氨基酸,所以一种氨基酸会对应不同密码子

耶鲁公开课 - 生物医学工程探索课程节选

I'd only have 16 possible two base sequences, that's not enough to specify over 20 amino acids.

如果两个碱基一组那一共只有十六种组合,不够和二十种氨基酸来一一对应

耶鲁公开课 - 生物医学工程探索课程节选