BY4.1 The Role of ATP

ATP Structure:

ATP consists of:

• an organic base (adenine)
• 5 carbon sugar (ribose)
• 3 phosphate groups

Importance of ATP:

An uncontrolled release of gluocse would lead to an increase in temperature that could destory cells

• short term energy store
• 'energy currency' of the cell
• hydrolysis of ATP releases energy as required

ATP = ADP+Pi

• an exergonic reaction
• energy is released (30kjmil/1)
• catalysed by the enzyme ATPase

ADP+Pi = ATP

• an endergonic reaction
• 30 kjmol/1 needed to add a phosphate group to ADP
• the energy is held in place by a high energy bond

Phosphorylation:

• phosphorylation of ATP (addition of a phosphate group) is a means of transferring free energy from energy rich compounds (gluocse) to cellular reaction

• 3 forms of phosphorylation
  • substrate level phosphorylation: chemical reactions release enough energy for phosphoryaltion to occur
  • oxidative phosphorylation: occurs in the membranes of mitochondira durig aerobic respiration
  • photophosphorylation: occurs in the membranes of chloroplasts during photosynthesis

Uses of ATP:

• active transport
• muscle contraction
• synthesis of materials wihtin cells
• nerve transmission

Advantages of ATP:

• only one enzyme is needed to…