An Introduction to Metabolism

An Introduction to Metabolism✴ Catabolic reactions - complex substance broken down into something less complex

✴ Combustion of gasoline (octane) is an example:

2C8H18

octane oxygen

25O2+

(complex) (simple)

16CO2

carbon dioxide water

18H2O+ + heat

water

6H2O6CO2carbon dioxide

sunlight + + C6H12O6glucose oxygen

6O2+

(simple) (complex)

✴ Anabolic reactions - complex substance is built from something less complex

✴ Production of sugar (glucose) in photosynthesis is an example:

✴ Metabolism - sum of all catabolic and anabolic reactions in an organism✴ These reactions, as all reactions in universe, follow laws of thermodynamics

Thermodynamics

First Law of ThermodynamicsTotal amount of energy in universe is constant

Energy cannot be created or destroyed, it can only be converted from one form to another

=

For example, burning of gasoline does not create energy; it just converts potential energy in chemical bonds to heat

PotentialEnergy

HeatEnergy+Potential

EnergyHeat

Energy+

For example, it is common to see a wine glass (ordered system) break into pieces (disordered system), but you will never see the broken pieces reforming into a wine glass on their own.

For example, it is common to see a wine glass (ordered system) break into pieces (disordered system), but you will never see the broken pieces reforming into a wine glass on their own

Second Law of Thermodynamics

Energy in universe is spontaneously flowing from higher to lower energy content

Universe is becoming more disordered

(entropy is increasing)