How do the two strands of DNA stay together?
2 Answers
The two strands of DNA stay together by H bonds that occur between complementary nucleotide base pairs.
Two hydrogen bonds occur between the adenosine and the thymine base pairs, and between the cytosine and the guanine there are three.
While each hydrogen bond is extremely weak (compared to a covalent bond, for example), the millions of H-bonds together represent an extremely strong force that keeps the two DNA strands together.
In addition, other groups of the base rings (polar groups) can form external hydrogen bonds with surrounding water that give the molecule extra stability.
The two strands of DNA stay together by H bonds that occur between complementary nucleotide base pairs.
Two hydrogen bonds occur between the adenosine and the thymine base pairs, and between the cytosine and the guanine there are three.
While each hydrogen bond is extremely weak (compared to a covalent bond, for example), the millions of H-bonds together represent an extremely strong force that keeps the two DNA strands together.
In addition, other groups of the base rings (polar groups) can form external hydrogen bonds with surrounding water that give the molecule extra stability.
