DNA Structure (OCR GCSE Biology A (Gateway))

DNA, or deoxyribonucleic acid, is the chemical molecule that contains the instructions for growth and development of all organisms

• DNA is the genetic material that determines the characteristics of all living organisms

• DNA carries a set of chemical instructions to make all the proteins required for life

• Except for identical twins every person's DNA is unique

DNA is contained in structures called chromosomes

In eukaryotic cells, chromosomes are located in the nucleus

• DNA is classed as a polymer (a molecule made from many repeating subunits called monomers)

  • Monomers are the small basic units that can make larger complex molecules

  • In DNA the individual monomers are called nucleotides

  • The nucleotides are joined together to form a single long chain/strand

DNA takes the form of a double helix

Two long polymer chains/strands of nucleotides coil around to make a double helix

• The double helix is a double-stranded spiral

• It is similar to a twisted ladder