关于专业和学术领域的东西，我想我还是出来说几句吧。

希望大家能够心平气和地思考问题，不要因为政治观念的不同，而影响学术判断。
 

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1,
Nucleic acids (DNA and RNA), are composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus. 是身体里最大结构分子。而组成DNA and RNA的基本结构单位成为核苷酸- Nucleotides

2，每一个核苷酸Nucleotides由三个部分组成：a nitrogenous base (also known as nucleobase), a five-carbon sugar (ribose or deoxyribose), and at least one phosphate group.

3， 决定核苷酸Nucleotides的区别性就在于这个nitrogenous base。这个 nitrogenous base, which can be either Adenine, Guanine, Cytosine, or Thymine (in the case of RNA, Thymine is replaced by Uracil).  我们简称这些nitrogenous base为： A, G, C, T, U

4，无数的核苷酸Nucleotides组成了一个chain (beads), 这个chain，也叫做strand.

Double stranded, forms a double helix 形状的是DNA，我们叫它DNA chain, or a DNA strand。

Single stranded (except in rare cases), can fold into complex 3D shapes, is relatively unstable and can leave the nucleus，就是RNA。

4，DNA and RNA are both strings of chemical building blocks called nucleotides (核苷酸）. And these nucleotides spell out a genetic code.

5，
For example, the DNA string "TATACGAAA" transcribes into the RNA string "UAUACGAAA", which in turn translates into the amino acid string "Tyr-Thr-Lys“  （氨基酸 string）

6，如果RNA string 的pattern改变了，基因code也会改变。RNA病毒变异快，也就不难理解了。

谢谢大家的耐心：）