Unit 2: Metabolic Processes Unit Questions: What is Energy? What is the biological definition of Energy? What is the connection between photosynthesis and cellular respiration? How do we obtain Energy from the food we eat?

Metabolic Processes in use! DALIAN (2007) - Over 23 tonnes of oil-eating bacteria are being used to clean up the oil spill off the coast of northeast China's Dalian City, four days after pipelines exploded near one of China's largest oil reserve bases.

Thermodynamics and Metabolism What is Energy? What is the biological definition of Energy? Refresher: What are the Equations for Photosynthesis and Cellular Respiration???

Metabolism Metabolism: all chemical reactions occurring in an organism Anabolism: chemical reactions that use energy to make new chemical bonds Ex. ??? Catabolism: chemical reactions that release energy when bonds are broken

Metabolism Metabolism: all chemical reactions occurring in an organism Anabolism: chemical reactions that use energy to make new chemical bonds Ex. Photosynthesis is an anabolic reaction Catabolism: chemical reactions that release energy when bonds are broken Ex. Cellular Respiration is a catabolic reaction

Flow of Energy Energy: the capacity to do work -kinetic energy: the energy of motion -potential energy: stored energy Energy can take many forms: mechanical electric current heat light

Think back to our biochemistry unit… What is a redox reaction???

Think back to our biochemistry unit… What is a redox reaction??? LEO the lion says GER!

Flow of Energy Potential energy stored in chemical bonds can be transferred from one molecule to another through electrons. oxidation: loss of electrons (LEO) reduction: gain of electrons (GER) redox reactions are coupled to each other.

Laws of Thermodynamics First Law of Thermodynamics – energy cannot be created or destroyed -energy can only be converted from one form to another Example: How does the process of photosynthesis demonstrate the first law of thermodynamics?

Laws of Thermodynamics First Law of Thermodynamics – energy cannot be created or destroyed -energy can only be converted from one form to another Example: sunlight energy chemical energy photosynthesis

Laws of Thermodynamics Second Law of Thermodynamics: disorder is more likely than order entropy: disorder in the universe The 2nd Law of Thermodynamics states that entropy is always increasing.

The messy bedroom law…

Laws of Thermodynamics: Gibb’s Free Energy Free energy: the energy available to do work -free energy symbol: G (Gibb’s free energy) enthalpy: energy contained in a molecule’s chemical bonds

Laws of Thermodynamics Chemical reactions can create changes in free energy. When products contain more free energy than reactants DG is positive. When reactants contain more free energy than products DG is negative.

Laws of Thermodynamics Chemical reactions can be described by the transfer of energy that occurs: endergonic reaction: a reaction requiring an input of energy - DG is positive exergonic reaction: a reaction that releases free energy - DG is negative

Laws of Thermodynamics Most reactions require some energy to get started. activation energy: extra energy needed to get a reaction started -destabilizes existing chemical bonds -required even for exergonic reactions catalysts: substances that lower the activation energy of a reaction *What do we call a catalyst that speeds up biological reactions?

Energy Currency of Cells ATP = adenosine triphosphate -the energy “currency” of cells ATP structure: -ribose, a 5-carbon sugar -adenine -three phosphates

How do we use ATP ATP stores energy in the bonds between phosphates. Phosphates are highly negative, therefore: -the phosphates repel each other -Lots of energy is required to keep the phosphates bound to each other -Lots of energy is released when the bond between two phosphates is broken

Energy Currency of Cells When the bond between phosphates is broken: ATP ADP + Pi energy is released ADP = adenosine diphosphate Pi = inorganic phosphate This reaction is reversible.

Energy Currency of Cells Is this an exergonic or endergonic reaction? ATP ADP + Pi energy is released

Energy Currency of Cells Is this an exergonic or endergonic reaction? ATP ADP + Pi energy is released EXERGONIC!

Energy Currency of Cells Is this an Is this an anabolic or catabolic reaction?? ATP ADP + Pi energy is released

Energy Currency of Cells Is this an Is this an anabolic or catabolic reaction?? ATP ADP + Pi energy is released CATABOLIC! *Exergonic reactions that occur in living things are catabolic, endergonic reactions in living things are anabolic

Energy Currency of Cells The energy released when ATP is broken down to ADP can be used to fuel endergonic reactions. The energy released from an exergonic reaction can be used to fuel the production of ATP from ADP + Pi.