Biological Molecules: the nucleotide ATP Flashcards
What is ATP used for in cells?
As the main energy source to carry out processes within cells
What are the 3 components of ATP?
3 phosphate groups, a ribose sugar and an adenine base
What does ATP stand for?
Adenosine triphosphate
How are the phosphate groups easily broken?
Because the bonds between the phosphate groups are unstable so have a low activation energy making them easy to break
How is energy stored in the ATP released?
The hydrolysis of the terminal phosphate (the 3rd one) as the bond is broken
Give the equation that shows ATP transferring energy
ATP + H20 -> ADP + Pi + E
E being energy
What catalyses the hydrolysis of ATP?
The enzyme ATP hydrolase
What reaction does ATP synthase catalyse?
The condensation of ADP and Pi to form ATP
Describe the ATP cycle
going from ATP to ADP, a molecule of water is required and an inorganic phosphate (Pi), and energy is released making it an exergonic process. Then going from ADP to ATP, a Pi and energy is required with a molecule of water being released making it an endergonic process.
What are the three ways synthesis of ATP to ADP occurs?
- Using light energy in photosynthesis (photophosphorylation)
- in plant and animal cells using glucose and other fuels in respiration (oxidative phosphorylation)
- using high energy phosphate substances in plant and animal cells when phosphate groups are transferred from donor cells to ADP (substrate-level phosphorylation )
For the formation of ATP from ADP and Pi, what kind of energy process is it and what kind of energy process are the reactions that fuel it?
The formation of ATP from ADP and Pi is an endergonic process that is fuelled by exergonic reactions
For the hydrolysis of ATP to ADP and Pi, what kind of energy process is it and what kind of energy process are the reactions that fuel it?
the hydrolysis of ATP to ADP and Pi is an exergonic process fuelled by endergonic reactions
What does exergonic and endergonic mean?
Exergonic releases energy and endergonic absorbs energy
Give two reasons ATP is a better immediate energy source than glucose
- Because each ATP molecule releases less energy than each glucose molecule, the energy for the reactions is released in much smaller and more manageable quantities than the energy released by 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 release takes longer
Why is ATP used in metabolic processes?
As it provides the energy needed to build up macromolecules from their basic units e.g. making starch from glucose or polypeptides from amino acids
How is ATP used in movement?
As in muscle contraction, ATP provides the energy for the filaments of muscle to slide past each other and therefor shorten the overall length of a muscle fibre
How is ATP used in active transport?
By providing energy to change the shape of carrier proteins in plasma membranes allowing molecules or ions to move against the concentration gradient
Why is ATP used in secretion?
As it’s needed to form the lysosomes need for secretion of cell products
How is ATP used in activation of molecules?
As the inorganic phosphate released during the hydrolysis of ATP can be used to phosphorylate other compounds in order to make them more reactive thus, lowering the activation energy in enzyme catalysed reactions e.g. the addition of phosphate to glucose molecules at the start of glycolysis
What energy requiring processes is ATP used for?
- metabolic processes
- movement
- active transport
- secretion
- activation of molecules
