3. DNA and the Production of Proteins

• DNA carries genetic information to make proteins. It has a double-stranded helix structure which is held together by complementary base pairs.
• DNA is composed of four bases

  1. A - Adenine
  2. T- Thymine
  3. G - Guanine
  4. C - Cytosine
• Cytosine pairs with Guanine.
• Thymine pairs with adenine.
• The four bases pair together to form a strand of DNA.
• The base sequence determines the amino acid sequence in proteins.
• A gene is a section of DNA which codes for a specific protein.
• mRNA is a molecule which carries a complementary copy of the genetic code from the DNA, in the nucleus, to a ribosome, where the protein is assembled from amino acids.
• Amino acids are joined together to form a protein at the ribosome.
• Different orders of base pairs have code for different proteins.