Energy

- cells convert energy in many ways
- organism's metabolism transforms matter and energy, subject to the laws of thermodynamics

Thermodynamics: study of energy transformations
3 Laws of Thermodynamics:
- Energy cannot be created or lost
- It takes energy to keep randomness in place (spontaneous changes that do not require outside energy increase the entropy, or disorder of the universe)
- Absolute Zero

- Living systems increase the entropy of the universe
- energy is required to maintain order

Free energy: energy that can do work under cellular conditions
- organisms live at the expense of free energy

Spontaneous change: free energy decrease, stability of system increases
- maximum stability: equilibrium (closed system)
- cells of our body constantly flows materials in and out, prevents metabolic pathways from reaching equilibrium

Exergonic reaction:
- release of free energy and is spontaneous
Endergonic reaction:
- absorbs free energy from surroundings and is not spontaneous

Metabolism:
- organism's chemical reactions
- arises from interactions between molecules
- it starts with a molcule and ends with a product, performed by a few specific enzymes

Catabolic pathways:
- complex molecules --> simple compounds
- releases energy
Anabolic pathways:
- simple compounds --> complex molecules
- consume energy

- Energy is the capacity to cause change which can perform work
- Energy can be converted

Kinetic energy:
- energy associated with motion
Potential energy:
- stored in the location of matter
- chemical energy stored in molecular structure

ATP:
- powers cellular work by coupling exergonic reactions to endergonic reactions
- 3 main types of work: mechanical, transport, chemical

Energy coupling: key feature in the way cells manage their energy resources to do this work
Couple Reaction: one releases energy, which fuels another