Nucleotides

• Nucleic acids: composed of Carbon, Hydrogen, Oxygen, Nitrogen, and Phosphorus (C, H, O, N, P)
• Nucleotides

  Nucleotides are monomers from which nucleic acid are made

  A nucleotide contains a pentose sugar, a base and a phosphate group

  Examples of polymers of nucleotides is DNA and RNA
• Joining together nucleotides

  A condensation reaction between two nucleotides form a phosphodiester bond to form a polynucleotide

  Hydrolysis breaks those bonds
• DNA nucleotides

  Deoxyribonucleic acid is the name for DNA

  Components of DNA are

  A deoxyribose sugar

  A phosphate group

  One of the organic bases
• RNA nucleotides

  Components of RNA

  Ribose sugar

  Phosphate group

  One of the bases but uracil replaces thymine
• DNA nucleotides pt2

  Draw out the nucleotide on paper

  
• DNA and RNA differences

  • DNA nucleotides have deoxyribose sugar while RNA has a ribose sugar
  • DNA nucleotides has a base called thymine while RNA has uracil in replace of thymine
  • RNA is a single stranded molecule while DNA is double stranded
• Ribose sugar

  Ribose sugars are pentose monosaccharides. Examples of molecules that have ribose are RNA,ATP and NAD

  
• Bases

  There are four bases

  • Adenine (A)
  • Guanine (G)
  • Cytosine (C)
  • Thymine (uracil replaces it in RNA nucleotides)
• Bases pt2

  Adenine and Guanine are purines so they have 2 carbon rings

  Cytosine and Thymine are pyramidines so they only have 1 carbon ring
• Bases pt3

  A bonds with T ( 2 hydrogen bonds)

  C bonds with G (3 hydrogen bonds)
• Structure of ATP

  ATP is adenosine triphosphate

  Components of ATP are

  Ribose sugar

  Adenine

  3 phosphate groups
• ADP

  ADP is formed through the hydrolysis of ATP. This process is catalysed by ATP hydrolase. ATP synthase catalysed the condensation reaction it ADP
• DNA structure

  Two strands of polynucleotides running in opposite directions The two sugar phosphate backbones are held in place by pairs of complementary bases joined by hydrogen bonds
• DNA structure pt2

  The phosphate group of a nucleotide forms a covalent bond ( phosphodiester bond ) with hydroxyl group in the sugar of another nucleotide.

  This forms the sugar phosphate backbone of the molecule
• DNA purification

  1. First grind the sample in a mortar and pestle to break down cell walls
  2. Mix sample with detergent to break cell membrane
  3. Add salt to break down any proteins involved with the DNA in the nuclei
  4. Add a layer of ethanol on top of sample to cause DNA to precipitate
• The genetic code

  The genetic code is carried as a sequence of three DNA bases called a triplets or colon
• Gene definition

  A gene is a sequence of triplets this determines the order of amino acids
• Genetic code pt2

  The genetic code is universal, non-overlapping and degenerate
• DNA replication ( semi - conservative) pt 2

  Semi-conservative replication of DNA ensures genetic continuity between generations of cells
• DNA replication ( semi-conservative)

  1. The enzyme called DNA helicase breaks hydrogen bonds between complementary base pairs
  2. The double helix unwinds and separates the two DNA strands
  3. New DNA nucleotides bind to exposed bases on the DNA template strand
  4. DNA polymerase catalyses the condensation reaction that joins adjacent nucleotides