ATP

components of ATP?

• adenine- a nitrogenous base

• ribose- a 5 carbon sugar

• three phosphate groups

how is an atp molecule made from its component molecules?

• condensation reaction of adenine, 3 phosphate groups and ribose

• with the use of atp synthase

• molecule of water is eliminated

is atp more similar to nucleotides from DNA or RNA?

• RNA

function of ATP?

• it is a small, relatively simple molecule

• can be thought of as the primary energy currency of cells

• atp is used to power most energy-requiring cellular reactions

why is ATP called a nucleotide derivate?

• because it is a modified form of a nucleotide

equation for the hydrolysis of ATP?

• ATP + H2O —> ADP + Pi (+energy)

  • hydrolysis of ATP to adenosine diphosphate (adp) and an inorganic phosphate group (Pi)

  • this reaction uses a water molecule so is called hydrolysis

what enzyme catalyses the hydrolysis of ATP?

• ATP hydrolase

what happens in the hydrolysis reaction?

• energy is released as one of the phosphate groups are broken

what is energy coupling?

• the hydrolysis of ATP can be coupled to other reaction within cells that need energy

  • this means the energy released can be used directly to make the coupled reaction happen, rather than being lost as heat

example of energy coupling?

• an example of energy coupling using ATP is the transmembrane sodium-potassium pump

  • energy is released from the hydrolysis of ATP

  • energy is needed to power the pump that drives the sodium ions out of the cel and the potassium ions into the cell

phosphorylation meaning?

• when the inorganic phosphate released in ATP hydrolysis can be used to phosphorylate other compounds

• this often makes the compounds more reactive

equation for the re synthesis of ATP/

• ADP + Pi (+energy) —> ATP + H2O

• ATP is resynthesised by the condensation of ADP and an inorganic phosphate.

what enzyme is used for the resynthesis of ATP?

• this reaction is catalysed by the enzyme ATP synthase during photosynthesis or respiration

what do cells rely on?

• the regeneration of ATP

  • since ATP hydrolysis releases energy, ATP regeneration must require an input of energy

why is atp a suitable energy source for cells to use?

• releases relatively small amount of energy

• releases energy instantaneously

• phosphorylates other compounds

• can be rapidly re-synthesised

• is not lost from cells/ does not leave cells

why is it necessary for humans to synthesise a large amount of ATP?

• it cannot be stored

• only releases a small amount of energy at a time