The Double-Helix Model The double-helix model explains chargaff's rule of base pairing and how the two strands of DNA are held togfther. The model showed the following.
- The two strands in the double helix run in opposite directions,with the nitrogenous bases in the center.
-Each strands carries a sequence of nucleotide,arranged almost like the letters in a fourletter alphabet for recorting genetic information.
-Hydrogen bonds hold the strands together. The bonds are easily broken allowing DNA strands to separate.
-Hydrogen bonds from only between ceatain base pairs-adenine with thymine,and cytosine with guanine. This is called base pairing.
strands
together