Energy, Catalysis and Biosynthesis

first law of thermodynamics

• energy cant be created or destroyed

• energy cant be transferred and change forms

second law of thermodynamics

• entropy (disorder) is always increasing

  • movement towards disorder is a spontaneous process

• no energy transfer is 100% efficient

  • some energy is lost as heat

• cells remain organized but do not defy the 2nd law (because the environment becomes disordered)

  • take in energy, generate order within

  • nonliving things do not have order

catabolism

turning food molecules into polymers (building blocks) for biosynthesis

• ½ of metabolism

• -∆G (exothermic)

• energy and heat released

  • more energetically favorable

anabolism

turning polymers into molecules the cell will use

• ½ of metabolism

• +∆G (endothermic)

• energy required

  • less energetically favorable

oxidation

loss of electrons

• cells obtain energy by the oxidation of organic molecules

• ex: C binding to O (O is more electroneg than C)

reduction

gain of electrons

• occurs as # of C-H bonds increases (H is less electroneg than C)