Ribose - A sugar molecule with
5-carbon ring structure that acts as
the backbone to the other parts
Phosphates -
A chain of
three
phosphate
groups
How ATP stores energy
Bonds between the 3
phosphate groups are unstable
and have a low activation
energy therefore easily broken
When they break a lot of
energy is released
ATP + H2O --> ADP + Pi + E
Adenine Triphosphate +
Water --> Adenine
Diphosphate + Inorganic
Phosphate + Energy
Synthesis of ATP
Water is used to convert ATP to ADP
This is a reversible reaction
and energy can be used to
add an inorganic phosphate
to ADP to re-form ATP
Occurs in 3 ways
In chlorophyll-containing plant
cells during photosynthesis
(photophosphorylation)
In plant and animal
cells during
respiration (oxidative
phosphorylation)
In plant and animal cells when
phosphate groups are transferred
from donor molecules to ADP
(substrate-level phosphorylation)
Roles of ATP
The immediate energy
source of a cell
Don't store large
quantities of ATP, only
a few seconds supply
Better than glucose as an
immediate energy source
ATP releases less
energy and quantities
are more manageable
Hydrolysis of ATP to ADP is a
single reaction and glucose is a
long series of reactions
Cannot be stored so is continuously made
in the mitochondria e.g muscle fibres
which require energy for movement
Used in energy-requiring processes in cells
Metabolic processes - for building up
macromolecules from basic units
Active transport - to change shape of
carrier proteins in plasma membranes
for molecules/ions to be moved
against a concentration gradient
Activation of molecules - inorganic phosphate can
be used to phosphorylate other compounds to
make them more reactive, lowering the activation
energy in enzyme-catalysed reactions
Secretion - form lysosomes for the secretion of cell products
Movement - provides energy for muscle contraction,
for filaments of muscle to slide past one another and
shorten the length of a muscle fibre