But in other parts of the world, and particularly for international itineraries involving multiple airlines, paper tickets are more common and it's taken 13 years from the time the first electronic ticket was issued in 1994 to the eradication of paper ticket stock issued by IATA.
The two DNA strands are held together by interchain hydrogen bonds. H-bonds pair the bases in one chain to the complementary bases in the other chain. (A/T and G/C). slide 2 of 4. Hydrogen Bonds in DNA A number factors are responsible for the stability of the DNA double helix structure, among them hydrogen bonds. Internal and external hydrogen bonds stabilize the DNA molecule. The two strands of DNA stay together by H bonds that occur between complementary nucleotide base pairs.
Secondary structure is the set of interactions between bases, i.e., which parts of strands are bound to each other. In DNA double helix, the two strands of DNA are held together by hydrogen bonds.The nucleotides on one strand base pairs with the nucleotide on the other strand. The secondary structure is responsible for the shape that the nucleic acid assumes.The bases in the DNA are classified as Purines and Pyrimidines.econdary structure is the set of interactions between bases, i.e., which parts of strands are bound to each other. In DNA double helix, the two strands of DNA are held together by hydrogen bonds.