ATP Structure and Energy

• ATP has a very similar structure to a nucleotide, it contains:

  • A ribose sugar
  • An adenine base
  • 3 phosphate groups

  
• Energy is stored in the bonds between the phosphates in ATP, when they are hydrolysed energy is released
• Phosphates that have been separated from ATP can be used to phosphorylate other molecules in cells to make them more reactive

  
• How ATP stores energy:

  Hydrolysis of ATP to Adenine DiPhosphate (ADP) and an inorganic phosphate group (Pi) is catalysed by the enzyme ATP hydrolase
• Hydrolysis of ATP:

  • The inorganic phosphate released during the hydrolysis of ATP can be used to phosphorylate other compounds, often making them more reactive
• Phosphorylation - The addition of a phosphoryl group to a molecule
• Eukaryotes oxidise organic molecules to make Adenine TriPhosphate (ATP), which is used as the main energy source within cells to carry out processes
• ATP is the immediate source of energy in a cell:

  1. Plant and animal cells release energy from glucose in a process called respiration
  2. Cells cannot get this energy directly from glucose so, in respiration, the energy released from glucose is used to make ATP
• Structure of ATP:

  • The nucleotide base Adenine
  • A ribose sugar
  • 3 phosphate groups

  
• Structure of ATP:

  Adenine - Nitrogen containing base
• Structure of ATP:

  Ribose sugar - A pentose sugar molecule

  • Acts as a backbone to which the other parts are attached
• Structure of ATP:

  Phosphates - A chain of three phosphate groups
• How ATP stores energy:

  THREE PHOSPHATE GROUPS - The bonds between these phosphate groups are unstable and so have low activation energy, which means they are easily broken

  • When they do break, they release a lot of energy
• How ATP stores energy: 3 PHOSPHATE GROUPS

  When the phosphate groups are broken, there is a hydrolysis reaction:

  ATP + H2O ---> ADP + Pi + Energy
• ATP + H2O ---> ADP + Pi + Energy

  • As water is used to convert ATP to ADP, this is known as a hydrolysis reaction
  • It is catalysed by the enzyme ATP hydrolase
• Synthesis of ATP:

  The conversion of ATP to ADP is a reversible reaction, and therefore energy can be used to add an inorganic phosphate to ADP to re-form ATP

  • This reaction is catalysed by the enzyme ATP synthase
  • As water is removed in this process, it is known as a condensation reaction
• Synthesis of ATP:

  The conversion of ATP to ADP is a reversible reaction, and therefore energy can be used to add an inorganic phosphate to ADP to re-form ATP

  • This reaction is catalysed by the enzyme ATP synthase
  • As water is removed in this process, it is known as a condensation reaction

  
• Synthesis of ATP from ADP involves the addition of a phosphate molecule, it occurs in 3 ways:

  • Photophosphorylation - In chlorophylll-containing plant cells during photosynthesis
• Synthesis of ATP from ADP involves the addition of a phosphate molecule, it occurs in 3 ways:

  • Oxidative Phosphorylation - In plant and animal cells during respiration
• Synthesis of ATP from ADP involves the addition of a phosphate molecule, it occurs in 3 ways:

  • Substrate-level phosphorylation - In plant and animal cells when phosphate groups are transferred from donor molecules to ADP
• A single molecule of Adenosine TriPhosphate (ATP) is a nucleotide derivative and is formed from a molecule of ribose, a molecule of adenine and three phosphate groups
• Synthesis of ATP:

  • ATP is resynthesised by the condensation of ADP and Pi
  • This reaction is catalysed by the enzyme ATP synthase during photosynthesis or respiration