Claudia asked in 科學及數學生物學 · 1 decade ago

Watson and Crick's model of DNA

How Watson and Crick's model of DNA has been validated over time??

如果可以,請用英文vocabuary作答, Thanks! 中文都可!

3 Answers

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  • 1 decade ago
    Best Answer

    Well..... According to the Watson-Crick model, a DNA molecule consists of two polynucleotide strands coiled around each other in a helical "twisted ladder" structure. As mentioned earlier in the tutorial, the sugar-phosphate backbone is on the outside of the double helix, and the bases are on the inside, so that a base on one strand points directly toward a base on the second strand. When using the twisted ladder analogy, think of the sugar-phosphate backbones as the two sides of the ladder and the bases in the middle as the rungs of the ladder. In effect, each strand of DNA is one-half of the double helix. The two halves come together to form the double helix structure.

    They also mention about DNA molecule is consist of 2 long polypeptide chain composed of 4 types of subunits: Adenine (A), cystosine (C), guanine (G) or thymine (T). Well, the reason that Watson and Crick's model of DNA validate over time because the structure of DNA haven't change since they invented the model. Further, the early x-ray diffraction results indicated that DNA was composed of 2 strands of the polymer wound into helix. The theory of H-bonding in between the 2 strand also is valid reason of the cause of double-helix. Further, nowadays technology have proven that the base subunit of DNA has linked together through the sugars and phospate on the subunit and which is the backbone of each strand sugar-phosphate-sugar-phosphate. This theory was also proposed by Crick and Watson, so it is valid over time as it is a valid reasoning of how DNA has its characteristic and the formation and composition of the double-helix.

  • 1 decade ago

    didn't address the "validation" aspect of the question at all

  • 1 decade ago

    ??

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