DNA + protein synthesis + genes

• A monomer is a small molecule that repeats to form and polymer
• A polymer is a large molecule made up of the same repeating monomers
• DNA is made from monomers called nucleotides
• A chromosome is made from one DNA molecule
• A gene is a section of a chromosome that codes for a protein
• DNA contains the genetic code that codes for proteins
• 1. The DNA contains the gene coding for the protein
  2. The DNA strands unzip and unwind around the gene. The DNA strand is used as a template to make a complimentary mRNA copy. This step is called transcription.
  3. The mRNA passes out of the nucleus and joins with a ribosome
  4. The ribosome uses the mRNA to join amino acids together in the correct order as determined by the base sequence
  5. The tRNA caries amino acids to the ribosomes in the correct order
  6. Many amino acids join together to make the final protein
• A mutation is a change in the DNA base sequence of a gene
• Causes of mutations:

  1. occur naturally due to errors in DNA replication
  2. ionising radiation eg. uv light, x-rays
  3. chemicals called mutagens eg. tar
• A mutation is a random change in the sequence of DNA bases