Lecture 6 – Reading
Energy Transformation I
Metabolic pathways consist of exergonic and endergonic reactions
- Metabolism: sum of all chemical reactions that rake place within an
- Exergonic Reaction: Releases free energy (delta D is negative)
- Endergonic Reaction: Consumes free energy (delta G is positive)
- Catabolic Pathway: energy is released by the breakdown of complex
molecules to simpler compounds. (Cellular respiration).
- Anabolic pathways: consumes energy to build complicated molecules from
simpler ones. Also called biosynthetic pathways. (Photosynthesis)
- Overall delta G of anabolic pathway is positive
- Overall delta G of catabolic pathway is negative
- Both pathways have many exergonic and endergonic reactions.
According to the second law of thermodynamics, energy transformations are never
100% efficient. Organisms must bring in much more energy than they actually
require. So living organisms are defined as hav