ATP and water

what are the 3 ways ATP is made?

1. photophosphorylation (photosynthesis)
2. oxidative phosphorylation (respiration)
3. substrate level phosphorylation

features of ATP

1. energy released in small, manageable quantities
2. immediate energy source - single step reaction
3. can be rapidly re-synthesised (reformed)
4. it does not leave cells
5. soluble

why do we need to synthesise such a large amount of ATP each day?

1. unstable
2. can’t be stored - it’s an immediate energy source
3. only releases a small amount of energy at a time

what are the uses of ATP in organisms?

1. provides energy and phosphate (Pi) to make molecules more reactive by lowering the activation energy of a reaction, e.g. by glycolysis
2. muscle contraction
3. active transport - to change the shape of carrier proteins in the membrane
4. building macromolecules, e.g. proteins
5. secretion - e.g. formation of lysosomes

describe how ATP is resynthesised in cells

1. from ADP and phosphate
2. by ATP synthase
3. during respiration

describe how an ATP molecule is formed from its component molecules

adenine, ribose and three phosphates joined by a condensation reaction using ATP synthase

explain five properties that make water important for organisms

1. a metabolite in condensation
2. a solvent so metabolic reactions can occur
3. high specific heat capacity so buffers changes in temperature
4. large latent heat of vaporisation so provides a cooling effect through evaporate
5. cohesion between water molecules so supports columns of water in plants
6. cohesion between water molecules so produces surface tension supporting small organisms