ATP Flashcards
Describe the structure of ATP
- ATP is a phosphorylated macromolecule.
- it has three parts:
1) Adenine (a nitrogen containing organic base)
2) Ribose (a sugar molecule with a five carbon ring structure that acts as the backbone to which the other parts are attached)
3) Phosphates (a chain of three phosphate groups)
What does ATP stand for
Adenosine triphosphate
Why is ATP a good donor of energy
The bonds between the three phosphate groups are unstable and so they have a low activation energy. This means that they are easily broken and when they do break they release a lot of energy.
How is ATP used to produce energy in living cells
- The terminal phosphate is removed according to the equation:
ATP+ H2O —> ADP +Pi + E - E stands for energy and Pi stands for inorganic phosphate.
What type of reaction is the conversion of ATP to ADP to release energy
Hydrolysis as water is used
What enzyme catalyses the reaction between ATP and water to form ADP and release energy
ATP hydrolase
How is ATP synthesised
- Through the condensation reaction of ADP with an inorganic phosphate- the reverse equation to the one for the conversion of ATP to ADP as the reaction is reversible.
What enzyme catalyses the reaction for the synthesis of ATP from ADP and an inorganic phosphate
ATP synthase
Describe the three ways in which ATP in synthesised from ADP and a phosphate molecule
- 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)
Why is ATP not a good energy store
For the same reasons it is a good energy donor- mainly the instability of the phosphate bonds.
Why is ATP a better immediate energy source than glucose
- Each ATP molecule releases less energy than each glucose molecule. The energy for reactions is therefore released in smaller, more manageable quantities than the much greater, and therefore much less manageable release of energy from a glucose molecule.
- The hydrolysis of ATP to ADP is a single reaction that releases immediate energy whereas the breakdown of glucose is a long series of reactions and therefore the energy releases takes longer.
Name the five key processes in cells that energy in the form of ATP is needed for
1) metabolic processes
2) movement
3) active transport
4) secretion
5) activation of molecules
Can ATP be stored
No. It has to be continuously made within the mitochondria of the cells that need it.
How is ATP used for metabolic processes
- ATP provides the energy needed to build up macromolecules from their basic units. For example making starch from glucose or polypeptides from amino acids.
How is ATP used for movement
ATP provides the energy needed for muscle contraction. In muscle contraction, ATP provides the energy for the filaments of muscle to slide past one another and therefore shorten the overall length of muscle fibre.
