DNA and production of proteins

• DNA is a double stranded helix and carries the genetic information to make a protein

  Gene is a section of DNA which codes for one protein
• The four bases in DNA are adenine, cytosine, guanine and thymine
• Cytosine always pairs with Guanine (GC)
• Adenine always pairs with Thymine (AT)
• Amino acids are the sub units of proteins
• The sequence of bases is important in DNA, as the sequence would determine the amino acid sequence in a protein
• mRNA carries a complementary copy of the DNA from the nucleus to the ribosomes within the cytoplasm. Since mRNA makes a copy of the DNA it is therefore made in the nucleus
• Protein synthesis is the process of making proteins from amino acids.
• Protein synthesis- the steps

  1. DNA uncoils and unzips
  2. a complementary strand of mRNA is made against the gene
  3. mRNA leaves the nucleus and travels to the ribosome in the cytoplasm
  4. the ribosome reads three bases at a time which codes for one amino acid
  5. it then continues to read the mRNA and a chain of amino acids are made and are assembled to form a protein