Question
What are the characteristics of DNA?
✓
Answer
Following are some features of DNA:
- DNA is made up of two polynucleotide chains, where the backbone is made up of sugar and phosphate groups and the nitrogenous bases project towards the centre.
- There is complementary base pairing between the two strands of DNA.
- The two strands are coiled in right-handed fashion and are anti-parallel in orientation. One chain has a 5′ → 3′ polarity while the other has 3′ → 5′ polarity.
- The diameter of the strand is always constant due to pairing of purine and pyrimidine, i.e., adenine is complementary to thymine while guanine is complementary to cytosine.
- The distance between two base pairs in a helix is 0.34nm and a complete turn contains approximately ten base pairs. The pitch of the helix is 3.4nm and the two strands are righthanded coiled.
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