Elucidating the structure of dna

Hence like proteins, DNA has secondary structure but in this case, the hydrogen bonds are not within the backbone but between the "side chain" bases on opposing strands.It is actually a misnomer to call ds DNA a molecule, since it really consists of two different, complementary strands held together by hydrogen bonds.The one discovered by Watson and Crick and found in most textbooks is called B-DNA.Depending on the actual DNA sequence and the hydration state of the DNA, it can be coaxed to form two other types of double-stranded helices, Z and A DNA. The 3.2 billion base pairs of DNA in humans contains about 24,000 short stretches (genes) that encode different proteins.

In complex (eukaryotic) cells, this packing problem is solved by coiling DNA around a core complex of four different pairs (eight proteins total) of histone proteins (H2A, H2B, H3, and H4) which have net positive charges.The history of Watson and Crick’s proposed DNA model is controversial and a travesty of scientific ethics.Rosalind Franklin was deeply involved in the determination of the structure of DNA, and had collected numerous diffraction patterns.The thymine (T) base on one strand can form two H-bonds with an adenine (A) base on the other strand (this is called an AT base pair).Double-stranded DNA has a regular geometric structure with a fixed distance between the two backbones.

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