ATP (c) Flashcards
What do cells require energy for?
- synthesis
- transport
- movement
what supplies the energy to cells?
ATP - adenosine triphosphate
what is an ATP molecule composed of?
A nitrogenous base, a pentose sugar and 3 phosphate groups - it is a nucleotide.
how is an ATP molecule different to the nucleotides in DNA and RNA?
The base is always adenine + there are 3 phosphate groups instead of one. Sugar is ribose, as in RNA nucleotides.
what is ATP used for?
ATP is used for energy transfer in all cells of all living things, hence known as the universal energy currency.
how does ATP release energy?
- energy is needed to break bonds and is released when bonds are formed
- small amount needed to break the relatively weak phosphate group in ATP but a large amount of energy is then released when the liberated phosphate undergoes other reactions involving bond formation.
- hydrolysis reaction since water is involved in the removal of the phosphate group
equation for this hydrolysis reaction
ATP + H2O –> ADP + P(i) + energy
Pi is the inorganic phosphate
why is ATP not a good long term energy source?
Because the phosphate bonds are unstable.
what is better for long term energy storage?
Fats and carbohydrates because the energy released in the breakdown of these molecules (cellular respiration) is used to create ATP.
what is phosphorylation?
The reattaching of a phosphate group to an ADP molecule. As water is removed in this process, it is a condensation reaction.
why is ATP a good immediate energy store?
Because ATP is rapidly reformed by the phosphorylation of ADP. This interconversion is happening constantly in all living cells, meaning cells do not need a large store of ATP.
properties of ATP
- small: easily moves into, out of and within cells
- water soluble: to provide energy to aqueous environments
- contains bonds between phosphates with immediate energy: large enough to be useful for cellular reactions but not so large that energy is wasted as heat.
- releases energy in small quantities: so energy is not wasted as heat
- easily regenerated: can be recharged with energy
