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3.3 identify that DNA is a double-stranded molecule twisted into a helix with each strand, comprised of a sugar-phosphate backbone and attached bases, adenine (A), thymine (T), cytosine (C) and guanine (G), connected to a complementary strand by pairing the bases, A-T and G-C
identify that DNA is a double-stranded molecule twisted into a helix with each strand, comprised of a sugar-phosphate backbone and attached bases, adenine (A), thymine (T), cytosine (C) and guanine (G), connected to a complementary strand by pairing the bases, A-T and G-C
- In summary, DNA is a nucleic acid in the shape of a double helix. Each strand of the helix consists of four different nucleotides made up of deoxyribose sugar, a phosphate molecule and a nitrogen base. The helix is like a twisted ladder. The backbones of the structure, or the sides of the ladder, consist of the deoxyribose sugar and phosphate molecules. The bases form the rungs between the sides of deoxyribose sugar and phosphate molecules and are complementary (only pair with their matching base). Adenine pairs with thymine and guanine pairs with cytosine.
Structure of DNA
Access Excellence, The National Health Museum, USA
Nucleotide
Access Excellence, The National Health Museum, USA