Chapter 2: Nucleic acids

• DNA

  deoxyribonucleic acid which is present in nearly all living organisms as the carrier of genetic information. double helix made of two polynucleotide chains, running antiparallel to eachother, with a sugar phosphate backbone on the outside and organic bases boned together by hydrogen bonds in the centre of the helix. The nucleotides have a deoxyribose sugar and the bases A T G C
• nucleotide

  complex chemicals made up of organic base, a sugar and a phosphate. basic units DNA and RNA are made out of
• polynucleotide 


  a polymer of the monomer nucleotide
• phosphodiester bond 


  the bond formed by condensation reaction between the phosphate group of the nucleotide and the penrose sugar of another nucleotide
• organic base 


  part of a nucleotide

  • A T C G U
• RNA


  a polynucleotide which contains nucleotides that have penrose sugar ribose rather than deoxyribose and contains bases A U C G. can be mRNA tRNA or rRNA
• complimentary base pairing 


  specific rules for how the bases pair together.

  • A with T with 2 H bonds
  • C with G with 3 H bonds
• double helix 


  structure of DNA made up of two strands of nucleotides running in opposite directions
• semi conservative replication


  the process in which the double helix of DNA molecule unwinds and each strand acts as a template on which a new strand is constructed
• DNA helicase 


  enzyme that acts on a specific region of DNA molecule to break the H bonds between the bases causing the two strands to separate and the nucleotides to be exposed in that region
• DNA polymerase 


  enzyme that joins DNA nucleotides together in a condensation reaction by forming phosphodiester bonds during DNA replication
• ADP 


  a nucleotide which combines in a condensation reaction catalysed by ATP synthesise, with a phosphate molecule of to form ATP
• ATP synthesise 


  an enzyme which catalyses the formation of ATP
• ATP hydrolase 


  an enzyme which catalyses the hydrolosis of ATP
• polymerases 


  group of enzymes that catalyse the formation of polymers from monomers
• specific heat capacity 


  amount of energy needed to change the temperature of 1kg of a substance by 1 degree C
• latent heat of vaporisation 


  the heat energy needed to change the substance from a liquid at its boiling point into gas at the same temperature
• cohesion 


  attraction between molecules of the same type. it is important in the movement of water up the xylem in a plant
• surface tension 


  the tension of the surface film of a liquid caused by the attraction of the particles in the surface layer by the bulk of the liquid
• solvent 


  the liquid in which a solute is dissolved in to form a solution
• inorganic ions 


  formed when an element or a compound, that doesn't contain carbon, gains or looses electrons to become negatively or positively charged

  eg hydrogen ions, phosphate ions, iron ions, sodium ions
• transparent 


  a material that allows light to pass through so that objects behind can be distinctly seen
• nucleotides are also found in ATP
• RNA

  1. stands for ribonuclease acid
  2. single relatively short polynucleotide
  3. penrose sugar made of ribose
  4. A C G U
  5. 4 types mRNA, tRNA, small interfering RNA, ribosomal RNA