cells and stuff

• DNA


  Double-stranded polymer of molecules called nucleotides
• Nucleotides


  • A
  • T
  • G
  • C
• A always pairs with T on the opposite DNA strand, and C always pairs with G
• Proteins


  Polymers of amino acids
• Amino acids


  • 20 different amino acids in humans
• Order of amino acids in a protein

  Determines the shape of the protein
• Shape of a protein

  Determines its function
• Gene


  Sequence of bases that determines the order of amino acids in a protein
• Protein synthesis


  1. Transcription (in nucleus)

  2. Translation (in cytoplasm)
• Transcription


  DNA sequence is copied into a complementary template molecule called mRNA
• Translation


  mRNA attaches to ribosome, amino acids are brought by tRNA and joined together in the correct order
• Once the protein chain is complete, it folds into its unique shape