DNA double helix

Rights Managed

SS2105370

P4445

DNA. Computer-generated model of a molecule of DNA (deoxyribonucleic acid). The DNA molecule consists of two helixes wound together. Phosphate and sugar chains (yellow) are joined by rungs (blue) consisting of four different chemicals called bases, each rung being made of two complementary bases. Genetic information is encoded in the sequence of base pairs along the molecule. When DNA replicates itself, the two helixes pull apart like a zip, and each side acts as a template for the construction of a new complementary strand. DNA is fundamental to almost all life on Earth. The first "organism" to appear on Earth is thought to have been a chemical with similar properties to DNA.

Kenneth Eward / BioGrafx / Science Source

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