3.1.6 ATP Flashcards
(26 cards)
What does ATP stand for
Adenosine triphosphate
Describe the structure of ATP
- Adenine
- base
- triphosphate
Describe the bonds between the phosphate groups
- Often called “high energy bonds”, yet they have a low activation energy, and so they’re unstable. This means that they are easily hydrolysed
Describe what happens when one of these “high energy bonds” are hydrolysed
- Energy is released, which can be used to power metabolic reactions
What are the 2 main roles of ATP in cells
- Release of energy to power metabolic reactions
- Phosphorylation of other molecules
Describe the process of phosphorylation (shape)
- The addition of a phosphate ion can change the shape of a molecule
- e.g. during active transport, a protein in the membrane changes shape to transport molecules across
Describe the process of phosphorylation (activation energy)
- The addition of a phosphate ion can lower the activation energy of other molecules, making them more reactive
- e.g during glycolysis (the first stage of respiration), glucose is phosphorylated to make it more reactive
Describe the hydrolysis reaction of ATP
ATP + H2O –> ADP + Pi (+ Energy)
- This reaction is catalysed by the enzyme ATP hydrolase
Describe the condensation reaction of ADP (resynthesised)
ADP + Pi –> ATP + H2O
- This reaction is catalysed by the enzyme ATP synthase during photosynthesis, or during respiration.
Explain why ATP is better intermediate energy source than glucose
- Each ATP releases less energy compared to glucose therefore this is more manageable for the cells.
- Additionally, the hydrolysis of ATP to ADP is a single step reaction, unlike the breakdown of glucose which is several steps and would take longer.
Describe what is meant by photophosphorylation
ATP is synthesised during photosynthesis
Describe what is meant by oxidative phosphorylation
ATP is synthesised during respiration
Describe what is meant by substrate-level phosphorylation
ATP is synthesised by the direct transfer of phosphate group to a molecule of ADP
Describe why ATP cannot be stored in cells
Due to unstable bonds between phosphate groups
Explain the advantages of ATP, in comparison to glucose.
- Each ATP molecule releases less energy than glucose, therefore, this is more manageable for the cells and more efficient
- The hydrolysis of ATP to ADP is a single reaction, therefore energy is released quickly, unlike glucose, which requires a long series of reactions to be broken down
- ATP can be easily reformed from ADP and Pi, therefore there is always a ready supply of ATP within cells, even though it cannot be stored
Adenosine triphosphate (ATP) is a nucleotide derivative.
Contrast the structures of ATP and a nucleotide found in DNA to give two differences.
- ATP has ribose and DNA nucleotide has deoxyribose;
- ATP has 3 phosphate (groups) and DNA nucleotide has 1 phosphate (group)
Scientists investigated the use of a new antibiotic to treat
bacterial infection. The new antibiotic inhibits the bacterial
ATP synthase enzyme. The new antibiotic is safe to use in
humans because it does not inhibit the ATP synthase found in human cells.
Suggest why human ATP synthase is not inhibited and
bacterial synthase is inhibited.
- Human ATP synthase has a different tertiary structure to bacterial ATP synthase
- Antibiotic not complementary (to human ATP synthase);
ATP is an energy source used in many cell processes. Give two ways in which ATP is a suitable energy source for cells to use.
- Releases relatively small amount of energy / little energy lost as heat;
Key concept is that little danger of thermal death of cells. - Releases energy instantaneously;
Key concept is that energy is readily available - Phosphorylates other compounds, making them more reactive;
- Can be rapidly re-synthesised;
- Is not lost from / does not leave cells
ATP is useful in many biological processes.
Explain why.
- Releases energy in small / manageable amounts;
. Accept less than glucose - (Broken down) in a one-step / single bond broken immediate energy compound
/ makes energy available rapidly;
2. Accept easily broken down - Phosphorylates / adds phosphate makes (phosphorylated substances) more reactive / lowers activation energy;
3. Do not accept phosphorus or P on its own
4. Reformed / made again;
4. Must relate to regeneration
Plants produce ATP in their chloroplasts during
photosynthesis. They also produce ATP during respiration.
Explain why it is important for plants to produce ATP during respiration in addition to during
photosynthesis.
- In the dark no ATP production in photosynthesis;
- Some tissues unable to photosynthesise / produce ATP;
- ATP cannot be moved from cell to cell / stored;
- Plant uses more ATP than produced in photosynthesis;
- ATP for active transport / synthesis (of named substance);
Humans synthesise more than their body mass of ATP each day.
Explain why it is necessary for them to synthesise such a large amount of ATP.
- ATP cannot be stored / is an immediate source of energy;
- ATP only releases a small amount of energy at a time;
Water is used to hydrolyse ATP.
Name the two products of ATP hydrolysis.
- Adenosine diphosphate
- (inorganic) phosphate
Cells constantly hydrolyse ATP to provide energy.
Describe how ATP is resynthesised in cells.
- From ADP and phosphate;
- By ATP synthase;
- During respiration/photosynthesis
Give two ways in which the hydrolysis of ATP is used in cells
- To provide energy for other reactions/named process; E.G. Active Transport
- To add phosphate to other substances and make them more reactive/change their shape
