Energy and Metabolism Flashcards
What is thermodynamics?
Branch of chemistry that focuses on energy changes
What is energy?
The capacity and ability to do work
What are the two main states of energy?
Kinetic energy and potential energy
What is kinetic energy?
Energy of motion
ex: Moving down a slide (doing work)
What is potential energy?
Stored energy
ex: At the top of the slide (stationary energy)
What is the most convenient way to measure energy?
Heat is the most convenient form of measuring energy.
1 calorie = heat required to raise a gram of water by 1 degree celsius.
What is a kilocalorie?
Most common unit of energy used in biology. Calorie on food labels with a capital C. (1000 calories)
What is the ultimate source of energy?
The sun is the ultimate source, as energy flows into the biological world from the sun.
What is bioenergetics?
How the flow of energy is described.
How is the sun’s energy captured?
Through photosynthesis, chlorophyll containing organisms capture the potential energy of the sun and store the energy in the form of chemical bonds.
What is oxidation?
Atom or molecule loses an electron.
What is reduction?
- Atom or molecule gains an electron.
- Have higher energy than oxidized form due to carrying high energy electrons. (more unstable)
What are the laws of energy?
- Energy cannot be destroyed or created.
- Energy can only change from one form to another.
- Total amount of energy in the universe remains constant.
- During each energy conversion, some energy is lost as heat.
What is entropy?
Entropy is the measure of disorder of a system that is continuously increasing as energy transformations proceed, going from more ordered/less stable to a less ordered/more stable form.
ex: Ice is more ordered → heat breaks down the h-bonds → changes ice to liquid form (more stable but less order) = highest entropy
What energy is available to do work?
- Not every chemical energy in bonds is available for work.
- Gibbs Free Energy (G) = energy available to do work.
How is Gibbs free energy (G) calculated (energy available to do work)?
G = H-TS
- H = enthalpy (energy in molecule’s chemical bonds)
- T = absolute temperature (K)
- S = entropy, unavailable energy.
What is endergonic?
- Not spontaneous absorption of energy from its surroundings in chemical reaction.
- Less free energy in reactant than products, therefore requires input of energy.
- Positive change in free energy.
- H (enthalpy) is higher, or S (entropy) is lower
- ex: Active transport, cell movement, anabolism
What is exergonic?
- Spontaneous release of energy to surroundings in chemical reaction.
- Does not require continuous energy supply but requires activation energy.
- More free energy in reactant than products.
- Negative change in free energy.
- H (enthalpy) is lower, or S (entropy) is higher
- ex: Cell respiration, catabolism
What is activation energy?
- The energy needed to break existing bonds.
- Larger activation energy proceed more slowly.
How can rate of exergonic reaction be increased?
- Heating reacting molecules to increase energy
- Lowering activation energy using catalysts
What is the role of catalysts?
- Make chemical bonds unstable to allow reactions take place.
- Lower activation energy becomes lower.
- Do not change thermodynamics.
- Do not alter ratio of reactants that turn into products.
- Speed up rate of reaction.
What is ATP?
The primary energy currency used by cells that is readily available. (Adenosine Triphosphate)