4.2 - Energy and ATP Flashcards
What is energy? (simple definition)
The ability to do work.
What SI unit is energy measured in?
J (Joules).
What happens to natural processes without an input of energy?
They break down in disorder.
State the 6 things energy is needed for in organisms?
- Metabolism
- Movement
- Active transport
- Maintenance, repair and division
- Production of substances
- Maintenance of body temperature.
What thermodynamic word could you use to describe birds and mammals, and why?
Endothermic - they lose heat to the environment and require energy to replace this.
What’s the first stage of energy flow through living systems?
Light energy from the Sun is converted by plants into chemical energy during photosynthesis.
What’s the second stage of energy flow through living systems?
Chemical energy from photosynthesis in the form of organic molecules is converted to ATP during respiration in all cells.
What’s the last stage of energy flow through living systems?
ATP is used by cells to perform useful work.
How does ATP store energy?
Bonds between phosphate groups are unstable, and so easily broken - low Eact. When terminal phosphate is broken, energy is released.
What type of reaction is the breaking down of ATP?
Hydrolysis (addition of water) & reversible.
What is the inverse of hydrolysis (and thus the type of reaction that converts ADP + Pi -> ATP again)?
Condensation (removal of water).
Name the three ways in which ADP is combined with Pi molecules?
- Photophosphorylation.
- Oxidative phosphorylation.
- Substrate-level phosphorylation.
Why is ATP a better energy source than glucose?
- Release less energy per molecule so more manageable.
- Hydrolysis of ATP to ADP is a single reaction - QUICK. Unlike many reactions to breakdown glucose.
Name 5 things ATP is a source of energy for.
- Metabolic processes
- Movement
- Active Transport
- Secretion
- Activation of molecules
What is the energy for ATP used for by metabolic processes?
It is used to construct macromolecules from it’s constituent units, [eg. polysaccharides from monosaccharides, polypeptides from amino acids, DNA/RNA from nucleotides.]
