Page 28 - Science Focus (Issue 016)

Cryptology in Biology: The Genetic Code 生物解碼：遺傳密碼

By Henry Lau 劉以軒

Instruction manuals tell people what to do. Similarly, 說明書告訴人們操作的方法。同樣地，脫氧核糖核酸
DNA (deoxyribonucleic acid) directs the various actions （DNA）指示細胞如何執行各類型的工作。正是如此，
of a cell. To perform this function properly, DNA stores DNA 儲存了一些訊息，它們可以被解碼成一些指令，告訴
information which can be decoded into instruction on 細胞如何利用氨基酸製造蛋白質。
how to use amino acids to produce proteins.

The decoding process is simpler than you might 解碼的過程比您想像的簡單！DNA 由四種核苷酸組
imagine! You see, DNA is made of four nucleotides: A, T, 成：A、T、C 和 G，一組三個的核苷酸組成一個資訊的單
C and G, and a series of three nucleotides form a unit of 位，稱為密碼子。連續地，每個密碼子編碼著一個氨基酸，
information called codons. In turn, each codon codes for 而每個氨基酸可以用一個英文字母代表，例如：「gat aac
one amino acid, which can be represented by a single gcg」可以解碼成「D N A」。
letter. For example, “gat aac gcg” can be translated into
“D N A”. 你能用這個原則來為下面的段落「解碼」嗎？
Can you apply this principle to solve the puzzle below? （假設 tag = B、tga = O、taa = U）
(Assume that tag = B, tga = O, taa = U)

(1) gataacgcg is the (2) tagttgtaagaaccccgcatcaacaca of life. Simply put, DNA stores information
that directs the synthesis of (3) ccgcgctgaaccgaaattaacagc. The entire process can be divided into
two actions: (4) acccgcgcgaacagctgccgcattccgaccatttgaaac and translation. In the former action,
information in DNA is copied into an intermediate called messenger (5) cgcaacgcg.
The intermediate is then translated into a chain of (6) gcgatgattaactga acids.

QR code: DNA codon chart and answer key
QR 碼：DNA 密碼子表及答案
http://sciencefocus.ust.hk/dna-codon-chart-issue-016

Acknowledgements 特別致謝
Print Advising 印刷諮詢
HKUST Media Technology and Publishing Center
香港科技大學媒體科技及出版中心

Special Thanks to 特別感謝
Kodansha Ltd. 講談社

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香港科技大學理學院出版

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