作为自然科学中的一个重要概念，cytosine是一个生物学术语，在学生的英语学习中也出现得比较频繁。以下从三个方面展开说明cytosine的含义和相关知识：
1. 定义和特点
Cytosine是一种含氮碱基，是DNA和RNA的四个碱基之一。其化学式为C4H5N3O，是一种嘌呤碱基。与DNA中的另外三种碱基(腺嘌呤、鸟嘌呤和胞嘧啶)一样，cytosine在DNA中起到存储遗传信息的作用。
2. 应用和意义
除了在基因中的重要作用外，cytosine还是许多药物、化学试剂和研究领域中常用的化合物之一。例如，研究人员使用cytosine分析DNA序列，研究细胞器和病菌。
3. 英文使用和例句
● “Cytosine is one of the four nucleotide subunits of DNA and RNA that are represented by the letters C, G, A, and T.”（Cytosine是DNA和RNA的四种核苷酸亚基之一，由字母C，G，A和T表示。）
● “Scientists have identified the structure of a protein that corrects errors in DNA replication, including those that cause drug resistance in cancer cells by changing cytosine to thymine.”（科学家们已经确定了一种纠正DNA复制中错误的蛋白质的结构，包括通过将胞嘧啶变成胸腺嘧啶，从而导致癌细胞耐药性的那些错误。）
● “Methylation is a chemical modification of DNA that involves adding a methyl group to the base molecule cytosine.”（甲基化是一种DNA的化学修饰，涉及向基础分子胞嘧啶添加甲基基团。）
● “This modification changes the shape of the DNA strand and makes it less accessible to the proteins that transcribe the gene, thereby reducing the expression of the cytosine-containing gene.”（此修饰会改变DNA链的形状，使其对于转录基因的蛋白质不那么易接近，从而降低持有胞嘧啶的基因的表达。）
● “Cytosine arabinoside is a chemotherapy drug that is used to treat different types of cancer, including acute myeloid leukemia and lymphoma.”（胞苷伯核苷是一种化疗药物，用于治疗不同类型的癌症，包括急性髓性白血病和淋巴瘤。）
cytosine的中文翻译为“胞嘧啶”，读音为“sa?t?si?n”。
例句：
1. Cytosine是DNA中的一种碱基。
胞嘧啶是DNA中的一种碱基。
2. 该研究发现了细胞中cytosine合成的新机制。
The study uncovered a new mechanism for cytosine synthesis in cells.
cytosine的中文解释是”胞嘧啶、核”，其中文解释还有”胞嘧啶”的意思，在线读音是[‘sait?si:n]，cytosine来源于英语，在《学生实用英汉双解大词典》中，共找到27个与cytosine相关的句子。
1.胞嘧啶
例句:Under normal conditions, a guanine matches with a cytosine, and an adenine with a thymine. (在正常情况下，鸟嘌呤与胞嘧啶配对，腺嘌呤配对胸腺嘧啶。)
2.核
例句:In a DNA nucleotide the nucleo base can be A, G, C or T, standing for the molecules adenine, guanine, cytosine or thymine; (DNA核苷酸里的碱基可能是腺嘌呤、鸟嘌呤、胞嘧啶或胸腺嘧啶，分别以A、G、C或T来表示。)
3.胞嘧啶
例句:Two potential Wells are found. One corresponds to the normal cytosine, while the other corresponds to its imino tautomer. (发现有两个势阱：其中一个对应正常的胞嘧啶，而另一个则对应它的顺式亚胺式互变异构体。)
4.胞嗪、胞嘧啶
例句:Researchers at purdue university used synthetic forms of guanine and cytosine. (翻译:美国普渡大学的研究人员使用的是合成的鸟嘌呤与胞嘧啶。)
cytosine一般作为名词使用，如在hydroxymethyl cytosine(羟甲基胞嘧啶)等常见短语中出现较多。
hydroxymethyl cytosine羟甲基胞嘧啶1. Two potential Wells are found. One corresponds to the normal cytosine, while the other corresponds to its imino tautomer. (翻译:发现有两个势阱：其中一个对应正常的胞嘧啶，而另一个则对应它的顺式亚胺式互变异构体。)
2. Researchers at purdue university used synthetic forms of guanine and cytosine. (翻译:美国普渡大学的研究人员使用的是合成的鸟嘌呤与胞嘧啶。)
3. This epigenetic information can be introduced by cytosine methylation and by marking nucleosomal histones. (翻译:这种表观遗传信息可以介绍的胞嘧啶甲基化和组蛋白标记核小。)
4. consequently they are commonly referred to simply by their purine or pyrimidineoriginal base components adenine, cytosine, guanine, thymine. (翻译:因此，他们通常被称为只要他们嘌呤或嘧啶在原有的基础上组成部分腺嘌呤，胞嘧啶，鸟嘌呤，胸腺嘧啶。)
5. Efficacy of antitumour colon cancer cell vaccine modified by eschrichia coli cytosine deaminase gene (翻译:胞嘧啶脱氨酶基因修饰的结肠癌细胞瘤苗抗肿瘤研究)
6. Adenine and guanine are purines and cytosine and thymine are pyrimidines. (翻译:腺嘌呤和鸟嘌呤是嘌呤和胞嘧啶和胸腺嘧啶是嘧啶。)
7. In certain bacteriophages, 5 – methylol cytosines have substituted for the cytosine. In the late 40s, looks up Garv e. (翻译:在某些噬菌体中，5 -羟甲基胞嘧啶取代了胞嘧啶。xx年代后期，查加夫。)
8. Adenine and guanine are purines and cytosine and thymine are pyrimidines. (翻译:腺嘌呤和鸟嘌呤是嘌呤和胞嘧啶和胸腺嘧啶是嘧啶。)
9. Cytosine, guanine, adenine and thymine. (翻译:胞嘧啶 鸟嘌呤 腺嘌呤和胸腺嘧啶 Cytosine, guanine, adenine and thymine.)
10. The other two, thymine and cytosine, are single ring structures called pyrimidines. (翻译:另两个为胸腺嘧啶和胞嘧啶，即称为嘧啶的单环结构。)
11. Methylation of cytosine residues is one of the most versatile mechanisms of epigenetic regulation. (翻译:胞嘧啶残基的甲基化是表观遗传调控的最复杂的机制之一。)
12. The team looked at methylation, in which a methyl group is placed onto cytosine in DNA sequences. (翻译:工作小组关注甲基化作用，是指一个甲基群被放在DNA序列的胞嘧啶上面。)
13. DNA consists of a chain made from four types of nucleotide subunits: adenine, cytosine, guanine, and thymine. (翻译:的DNA链组成一个由4种核苷酸亚基：腺嘌呤，胞嘧啶，鸟嘌呤和胸腺嘧啶。)
14. The genomes of many animals, plants and fungi are tagged by methylation of DNA cytosine. (翻译:的基因组的许多动物，植物和真菌有标记的甲基化的DNA胞嘧啶。)
15. Currently, the most active area of research involves introducing one of the cytosine genes into the cancer cell. (翻译:目前，最活跃的研究领域涉及引进一个胞嘧啶基因进入肿瘤细胞。)
