Two chains of a DNA molecule are held against each other by hydrogen bonds. Determine the number

| September 26, 2021 | education

Two chains of a DNA molecule are held against each other by hydrogen bonds. Determine the number of nucleotides with adenine (A), thymine (T), guanine (G) and cytosine (C) in a DNA molecule, in which 36 nucleotides are linked by three hydrogen bonds and 18 nucleotides – two hydrogen bonds, Explain the results obtained.

Hydrogen bonds in a DNA chain are formed between complementary nucleotides. Adenine is associated with thymine, guanine with cytosine.

In this case, a double bond is formed between adenine and guanine, and a triple bond between guanine and cytosine.

1) Find the amount of adenine and thymine.

18 nucleotides with a double hydrogen bond – in two chains, respectively, 18/2 = 9 AT pairs are formed. Adenine and thymine, 9 molecules each.

2) 36 nucleotides with a triple bond are 18 pairs of G-C or 18 molecules of guanine and cytosine.



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