Metabolism and Metabolic Pathways
Metabolism = 2 definitions:
1) The sum total of the chemical processes that occur in living organisms, resulting in growth,
production of energy, elimination of waste material, etc.
2) The sum total of the chemical processes affecting a particular substance in the body: e.g.
carbohydrate metabolism; iodine metabolism, etc.
Bioenergetics = Study of flow of energy in living systems:
- Autotrophs (e.g. plants) use solar energy and CO2 to make energy-rich molecules (e.g. –
carbs)
- Heterotrophs (e.g. humans) obtain energy in chemical form by degrading molecules made
form autotrophs
Energy = ability to move/change matter
- Kinetic energy = energy of motion
- Potential energy = stored energy
- Chemical energy = stored energy available for release
Autotrophs/Heterotrophs ≠ heat for energy
Autotrophs/Heterotrophs only use Gibb’s free energy (amount of energy capable for doing work e.g.
– ‘free’ solar energy and ‘free’ chemical energy
(Remember, endergonic reaction needs free energy (non-spontaneous) exergonic reaction releases
energy and includes many catabolic reactions)
The chemical energy stored in bonds = due to arrangement of E- in the bonds between their atoms
Metabolic pathways are very complex and break down into 2 main aims:
- Convert nutrient molecules into precursors for cell’s own molecules, build up
larger/macromolecules using the precursors
- Degrade organic molecules into smaller end products (e.g. – lactic acid, CO2)
Anabolic and Catabolic reactions = metabolic terms
Manufacture of proteins from aa = anabolic
Breakdown of glucose during cellular respiration = catabolic
Energy released from catabolic reactions can be used to drive anabolic reactions
Metabolism = 2 definitions:
1) The sum total of the chemical processes that occur in living organisms, resulting in growth,
production of energy, elimination of waste material, etc.
2) The sum total of the chemical processes affecting a particular substance in the body: e.g.
carbohydrate metabolism; iodine metabolism, etc.
Bioenergetics = Study of flow of energy in living systems:
- Autotrophs (e.g. plants) use solar energy and CO2 to make energy-rich molecules (e.g. –
carbs)
- Heterotrophs (e.g. humans) obtain energy in chemical form by degrading molecules made
form autotrophs
Energy = ability to move/change matter
- Kinetic energy = energy of motion
- Potential energy = stored energy
- Chemical energy = stored energy available for release
Autotrophs/Heterotrophs ≠ heat for energy
Autotrophs/Heterotrophs only use Gibb’s free energy (amount of energy capable for doing work e.g.
– ‘free’ solar energy and ‘free’ chemical energy
(Remember, endergonic reaction needs free energy (non-spontaneous) exergonic reaction releases
energy and includes many catabolic reactions)
The chemical energy stored in bonds = due to arrangement of E- in the bonds between their atoms
Metabolic pathways are very complex and break down into 2 main aims:
- Convert nutrient molecules into precursors for cell’s own molecules, build up
larger/macromolecules using the precursors
- Degrade organic molecules into smaller end products (e.g. – lactic acid, CO2)
Anabolic and Catabolic reactions = metabolic terms
Manufacture of proteins from aa = anabolic
Breakdown of glucose during cellular respiration = catabolic
Energy released from catabolic reactions can be used to drive anabolic reactions
