Energy and ATP Flashcards
What does ATP stand for?
Adenosine triphosphate
What kind of molecule is an ATP molecule?
A phosphorylated macromolecule
What are the 3 parts of an ATP molecule?
Adenine - a nitrogen containing organic base
Ribose - a sugar molecule with a 5 carbon ring(pentose sugar) that acts as the backbone to which the other parts are attached
Phosphates - a chain of 3 phosphate groups
What is just adenine and ribose known as?
Adenosine
What is just adenine, ribose and 1 phosphate group known as?
Adenosine monophospahte (AMP)
If it has 2 phosphate groups, it is known as Adenosine diphosphate (ADP)
How does ATP store energy?
- It is a nucleotide and has 3 phosphate groups
- The bonds between these groups are unstable and have a low activation energy, so they are easily broken
What happens when the bonds between the phosphate groups in an ATP break?
They release a considerable amount of energy
What usually happens in living cells in the hydrolysis of an ATP molecule?
Only the terminal phosphate is removed
What is the hydrolysis equation of ATP?
ATP + H2O = ADP + P(inorganic phospate) + E
What is the hydrolysis reaction of ATP catalysed by?
The enzyme ATP hydrolyse (ATPase)
What kind of reaction is the conversion of ATP to ADP and hence, what does this mean?
Reversible so energy can be used to add an inorganic phosphate to ADP to re-form ATP (synthesis of ATP)
What is the synthesis of ATP catalysed by?
The enzyme ATP synthase
What kind of reaction is the synthesis of ATP?
As water is removed, the reaction is known as a condensation reaction
In what 3 ways does the synthesis of ATP from ADP occur?
In chlorophyll
In plant and animal cells (this is in 2 different ways)
How does the synthesis of ATP occur in chlorophyll?
In chlorophyll containing plant cells during photosynthesis (photophosphorylation)
How does the synthesis of ATP occur in plant and animal cells?
- During respiration (oxidative phosphorylation)
- When phosphate groups are transferred from donor molecules to ADP (substrate level phosphorylation)
What is the role of ATP?
It is the immediate energy source of a cell (not long term due to instability of phosphate bonds)
In what quantities do cells store ATP?
- In small quantities, just a few seconds supply
- This is not a problem as ATP is regularly re-formed from ADP and inorganic phosphate (Pi)
Why is ATP a better immediate energy source than glucose?
- Each ATP molecule releases less energy than each glucose molecule so the energy for reactions is released in smaller, more manageable quantities
- The hydrolysis of ATP to ADP is a single reaction that releases immediate energy. The breakdown of glucose is a long series of reactions and so the release of energy is longer
Why do cells that require a lot of energy have many large mitochondria?
ATP cannot be stored and so has to be continuously made in the mitochondria of cells that need it
Which processes is ATP used in?
Metabolic processes
Movement
Active transport
Secretion
Activation of Molecules
How is ATP used in metabolic processes?
Provides the energy needed to build up macromolecules from their basic units e.g. starch from glucose
How is ATP used in movement?
Provides energy for muscle contraction. Provides energy for the filaments of muscle to slide past one another and shorten the overall length of a muscle fibre
How is ATP used for active transport?
Provides energy to change shape of carrier proteins in plasma membranes. Allows molecules or ions to be moved against a concentration gradient
How is ATP used for secretion?
Needed to form the lysosomes necessary for the secretion of cell products
How is ATP used for the activation of molecules?
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
