L1 - DNA Structure and Function

• DNA forms a double helix shape
• In DNA there is a sugar phosphate backbone made from alternating sugar and phosphates
• DNA has two back bones which are connected by bases
• The complimentary base pairs are A-T and G-C. Adenine always pairs with thymine, and guanine always pairs with cytosine. The shape of the bases compliment each other. The ratio of the complimentary bases is always 1:1 regardless of the species. However, the percentage or mass of the bases in different species will be different.
• Gene


  A section of DNA which codes for a protein
• Every 3 bases (a triplet) code for one amino acid
• Amino acids join together to form a protein (protein synthesis)
• The order of amino acids determines which particular protein is made - a different order produces a different protein