DNA

• DNA

  A double-stranded polymer of nucleotides, wound to form a double helix
• Monomers of DNA

  Nucleotides
• DNA nucleotides composition

  Common sugar, phosphate group, one of four bases: A, T, C or G
• Four bases in nucleotides

  Adenine, Thymine, Cytosine, Guanine
• Nucleotide interaction in DNA

  Sugar and phosphate molecules join to form a sugar-phosphate backbone in each DNA strand; base connected to each sugar; complementary base pairs (A pairs with T, C pairs with G) joined by weak hydrogen bonds
• Genome

  The entire genetic material of an organism
• Chromosome

  A long, coiled molecule of DNA that carries genetic information in the form of genes
• Gene

  A section of DNA that codes for a specific sequence of amino acids which undergo polymerisation to form a protein
• DNA extraction method from fruit

  1. Place a piece of fruit in a beaker and crush it 2. Add detergent and salt, mix 3. Filter the mixture and collect the liquid in a test tube 4. Pour chilled ethanol into the test tube 5. DNA precipitates forming a fibrous white solid 6. Use a glass rod to collect the DNA sample
• Detergent in fruit extraction

  It disrupts the cell membranes, releasing DNA into solution
• Salt in fruit extraction

  Salt encourages the precipitation of DNA
• Chilled ethanol in extraction

  DNA is insoluble in ethanol, encouraging its precipitation
• Gene coding for a protein

  A sequence of three bases in a gene forms a triplet; each triplet codes for an amino acid; the order of amino acids determines the structure (i.e. how it will fold) and function of protein formed
• Protein synthesis


  The formation of a protein from a gene
• Mutation

  A random change in the base sequence of DNA which results in genetic variants