Metabolism
Metabolism is the set of chemical reactions that keep a cell running: breaking molecules down to release energy, and building molecules up to make and repair structures. The breaking-down half is called catabolism and the building-up half anabolism. Nearly every step is run by an enzyme, a protein that speeds up one specific reaction, which is why metabolism can be steered by changing which proteins a cell makes.
Why it matters
It is the answer to how organisms stay ordered in a universe that tends toward disorder: they spend energy continuously to do it.
Where it comes up
Read about Metabolism on Wikipedia
Sources
- Metabolism Wikipedia
- Cell Energy, Cell Functions Nature Education ScitableA short introduction to how cells capture and spend energy.
- Molecular Biology of the Cell NCBI Bookshelf
