What is the Structure of DNA, the Macromolecule ?
DNA is a nucleic acid – a polymer – that contains multiple copies of the 4 nucleotide monomers – Adenine (A), Cytosine (C), Guanine (G), and Thymine (T) arranged in a spiral staircase shape – the DNA double helix. The nucleotides, when joined together, polymerize to form a long strand, the backbone of which is repeating sugar and phosphate groups that twist around each other to form a double helix “staircase”. The backbone, or “stair rails” consists of repeating nucleotides joined sugar-to-phosphate – a sugar-phosphate backbone The nitrogenous bases, “rungs”, are held together by weak hydrogen bonds between the A and T and the C and G nucleotides: The structure of the DNA Double Helix. Note the “sugar-phosphate backbone” (red ribbons) and the “rungs” made up of the blue bases A, C, G and T How much DNA is in a human cell? Every cell in your body (only exception: mature red blood cells!) has a nucleus packed with DNA, tightly coiled and condensed around histone proteins to make it all f
