DNA structure

• What is DNA?

  A polymer made up of repeating units called nucleotides
• What does each nucleotide consist of?

  A sugar , a phosphate and a base ( A , C , G or T )

  
• Nucleotides in DNA join together to form long strands
• DNA contains 4 different nucleotides
• DNA is molecule of DNA is made up of 2 alternating sugar and phosphate strands that are twisted to form a double helix
• In a nucleotide , attached to each sugar is one of the four bases

  
• The same bases always pair to the opposite strand - A pairs to T -C pairs to G
• What holds the two bases together?

  An attraction between the different bases