DNA

• DNA stands for deoxyribonucleic acid where all of the genetic material in a cell is made up from
• DNA is a polymer known as nucleotides
• shape of DNA

  double helix
• DNA is found in the nucleus
• chromosomes

  long structures found in DNA molecule
• there are 4 DNA bases

  • adenine
  • thymine
  • cytosine
  • guamine
• 3 components of DNA

  • sugar
  • phosphate
  • base
• gene

  small section of DNA found on a chromosome
• genome

  entire set of genetic material of an organism
• codon

  sequence of three bases in the DNA
• two stages of protein synthesis

  • transcription
  • translation
• transcription

  • RNA polymerase binds to a region of non-coding DNA in front of a gene
  • the 2 DNA strands separate and RNA polymerase moves along one of the strands of DNA
  • it uses the coding DNA in the gene as a template to make mRNA where the base proteins between DNA & RNA is complementary
  • once mRNA is made molecule moves out of nucleus and goes to a ribosome in the cytoplasm
• translation

  • amino acids are brought to ribosomes by another RNA molecule called tRNA
  • the order in which the amino acids are brought to the ribosomes matches order of codons in the mRNA
  • amino acids are joined together by the ribosome to make a protein
• mRNA

  acts as a messenger and carries the code to the ribosomes
• types of proteins

  • enzymes - biological catalysts to speed up chemical reactions in the body
  • hormones - carry messages around the body
  • structural proteins - are physically strong
• genetic mutations

  • non-coding parts of DNA
  • impact genes by switching them on or off
  • proteins are not made or too many of them are made
• 3 types of mutation

  A) substitution

  B) deletion

  C) insertion