The energy currency
ATP stores and gives out energy.
A rechargeable battery
A battery can be charged and then used to run a torch, a toy or a clock.
Which cell molecule do you think acts a little like a battery for the cell?
What this lesson covers
The idea
Energy released in respiration goes into making ATP from ADP and inorganic phosphate; breaking ATP's terminal phosphate linkage using water releases a fixed amount of energy (30.5 kJ/mol) that drives the cell's endothermic reactions.
A rechargeable battery
A battery can be charged and then used to run a torch, a toy or a clock.
Which cell molecule do you think acts a little like a battery for the cell?
- ATP
- Water
- Starch
Charge and use
Open each tab to see how ATP is made, broken and used.
A cell battery
The energy released in respiration is not used directly for every job. It is used to make ATP from ADP and inorganic phosphate. When the terminal phosphate linkage in ATP is broken using water, a fixed amount of energy is released, 30.5 kJ per mole, and the cell uses it to drive its endothermic reactions.
Energy released in respiration goes into making ATP from ADP and inorganic phosphate; breaking ATP's terminal phosphate linkage using water releases a fixed amount of energy (30.5 kJ per mole) that drives the cell's endothermic reactions.
Notes
Respiration's energy makes ATP (from ADP and inorganic phosphate); breaking its terminal phosphate linkage with water releases 30.5 kJ per mole, which drives the cell's endothermic reactions.
Check yourself
What is used to make an ATP molecule?
What is used to break the terminal phosphate linkage in ATP?
Breaking the terminal phosphate linkage of 1 mole of ATP releases 30.5 kJ. How much energy is released for 3 moles? (in kJ)
Answer: 91.5 kJ
3 × 30.5 kJ = 91.5 kJ.
Which of these is something ATP can be used for in cells?
- Light energy absorbed by chlorophyll. Chlorophyll absorbs light energy during photosynthesis; ATP is made with the energy released in respiration.
- Energy released in respiration, with ADP and inorganic phosphate — correct. Yes!
- Water alone. Water is used to break the terminal phosphate linkage of ATP, not to make it.
- Oxygen. Oxygen is used when pyruvate is broken down in the mitochondria.
- Glucose. Glucose is broken down to pyruvate in the cytoplasm.
- Water — correct. Yes!
- Contraction of muscles — correct. Yes!
- Absorbing light energy. Absorbing light energy is done by chlorophyll in photosynthesis.
- Taking in oxygen through the nostrils. Air is taken in through the nostrils by breathing; the book lists muscle contraction, protein synthesis and conduction of nervous impulses as uses of ATP.