nucleotides

• a nucleotide is made from

  • pentose sugar (5 carbon)
  • nitrogenous base
  • phosphate group
• all nucleotides contain elements : C, H, O, N and P
• nucleotides are monomers that make up DNA and RNA which are both types of nucleic acid
• DNA Is used to store genetic information- the instructions an organism needs to grow and develop
• RNA - is used to make proteins from the instructions in DNA
• ADP and ATP are special types of nucleotide and are used to store and transport energy in cells
• the pentose sugar in DNA nucleotide is called deoxyribose
• each DNA nucleotide has the same sugar and a phosphate group. the base on each nucleotide can vary though.
• 4 bases :

  1. Adenine
  2. Thymine
  3. Cytosine
  4. Guanine
• purine - contains 2 carbon-nitrogen rings joined together e.g. Adenine and Guanine
• pyrimidine- base only has 1 carbon-nitrogen ring so is smaller. e.g. Cytosine and Thymine
• the sugar in RNA is called ribose
• RNA contains nucleotides with a ribose sugar
• RNA nucleotide also has a phosphate group and 1 of 4 different bases
• in RNA uracil replaces thymine as a base
• an RNA molecule is made form a single polynucleotide chain
• ADP and ATP are phosphorylated nucleotides
• to phosphorylate a nucleotide, you add 1 or more phosphate groups too it
• ADP contains the base adenine, sugar ribose and 2 phosphate groups
• ATP contains base adenine, the sugar ribose and 3 phosphate groups
• ATP provides energy for chemical reactions in the cell
• ATP is synthesised from ADP and inorganic phosphate using the energy from an energy-releasing reaction e.g. breakdown of glucose in respiration.

  ADP Is phosphorylated to form ATP and a phosphate bond is formed
• energy is stored in the phosphate bond. when this energy is needed by a cell, ATP is broken back down into ADP and inorganic phosphate. Energy is released from the phosphate bond and used by the cell