Bio wa 2

• DNA


  Consists of 4 nucleotides, each with a phosphate group, sugar, and base
• DNA structure


  • Phosphate groups link nucleotides to form a single strand
  • Adenine (A) pairs with Thymine (T)
  • Cytosine (C) pairs with Guanine (G) through hydrogen bonds to form double stranded DNA molecules
  • Double helix coiled from 2 strands of polynucleotide
• DNA molecule


  Made up of nucleotides containing nitrogenous bases, enabling specific codes to be carried in the form of nucleotide sequences called genes
• Genes, chromosomes and DNA

  • DNA is a polynucleotide consisting of phosphate group, deoxyribose sugar and nitrogenous base
  • Chromosome is a double-stranded DNA molecule wrapped around histone proteins
  • Segments of chromosome that code for a polypeptide is referred to as a gene
• How a polypeptide or protein is made

  1. Message in the gene is copied into an mRNA in the nucleus

  2. mRNA travels to cytoplasm and attaches to a ribosome

  3. Ribosome moves along mRNA, synthesising a polypeptide

  4. When ribosome leaves mRNA, the polypeptide is released
• Translation


  Ribosome reads the information in the mRNA, assembling amino acids to synthesise a polypeptide
• Transcription


  Gene is copied in the nucleus through transcription, to produce an mRNA strand