Making Protiens

• What controls the order in which amino acids are joined together to make a particular protein?

  The order of bases in DNA
• The sequence of 3 bases is the code for 1 amino acid
• Proteins are polymers of amino acids
• How many different amino acids are there in humans?

  20
• The order of amino acids determines the shape of the protein , and the shape of the protein determines its function
• Collagen is a structural protein
• Amylase is a protein that is an enzyme molecule
• Insulin is a protein that is a hormone
• What are proteins synthesised on?

  They are synthesised on ribosomes , by using a template that has been taken from the DNA and carried out of the nucleus
• Describe protein synthesis?

  The base sequence of the gene is copied into complementary template molecule - this template is called mRNA (a single stranded molecule) - The mRNA passes from the nucleus into the cytoplasm - The mRNA attaches to a ribosome - amino acids are brought to the ribosome on carrier molecules (tRNA) - The ribosome reads the 3 bases on the mRNA and joins together the correct amino acids in the correct order - Once complete, the protein chain folds into its unique shape - the shape allows the protein to do its job
• The first stage of protein synthesis is transcription and takes place in the cytoplasm
• The second stage of protein synthesis is called translation and takes part in the nucleus