Introduction to Bioenergetics/Bioenergetics-I

 

 What is Bioenergetics?

The study of energy in living systems (environments) and the organisms (plants and animals) that utilize them

Energy:-

 Required by all organisms

May be Kinetic or Potential energy

Kinetic Energy:-

*  Energy of Motion

*  Heat and light energy are examples

Potential Energy:-

Energy of position

Includes energy stored in chemical bonds

Two Types of Energy Reactions

Endergonic Reactions:-   Chemical reaction that requires a net input of energy.  

 Ex- Photosynthesis

            6CO₂  +         6H₂O ®       C₆H₁₂O₆  +  6O_{2 ( This reaction requires energy in the form of photon)} 

_{Exergonic Reactions:-} Chemical reactions that releases energy

_{Ex- Cellular Respiration}

 _{C6H12O6  + 6O2  ® 6CO2 + 6H2O + ATP(energy)}

         

Metabolic Reactions of Cells

 

The sum total of the chemical activities of all cells.

Two Types of Metabolism

Anabolic Pathways

Catabolic Pathways

 

Anabolic Pathway

Metabolic reactions, which consume energy (endergonic), to build complicated molecules from simpler compounds.

Photosynthesis

            6CO₂   +  6H₂O  ®  C₆H₁₂O₆   + 6O_{2 (This reaction takes place in the presence of sunlight with the help of chlorophyll pigment)} 

 

Catabolic Pathway

Metabolic reactions which release energy (exergonic) by breaking down complex molecules in simpler compounds

Cellular Respiration

 C₆H₁₂O₆ + 6O₂   ® 6CO₂  +  6H₂O  + ATP

 

 

Cellular Energy – ATP

                                                         ATP(Adenocine Tri-phosphate)

Components:

            1. adenine: nitrogenous base

            2. ribose:     five carbon sugar

            3.phosphate group:  chain of 3 phosphate

Three phosphate groups-(two with high energy bonds Last phosphate group (PO₄) contains the MOST energy

 

 Breaking the Bonds of ATP:-

Process is called phosphorylation

Occurs continually in cells

Enzyme ATP-ase can weaken & break last PO₄ bond releasing energy & free PO₄

 How does ATP work?

Organisms use enzymes to break down energy-rich glucose to release its potential energy

This energy is trapped and stored in the form of adenosine triphosphate(ATP)

 It is estimated that each cell will generate and consume approximately 10,000,000 molecules of ATP per s

 

Coupled Reaction – ATP

The exergonic hydrolysis of ATP is coupled with the endergonic dehydration process by transferring a phosphate group to another molecule.

 

Hydrolysis of ATP

ATP  +  H₂O  ®    ADP +  P   (exergonic)

Hyrolysis is Exergonic

Dehydration of ATP

ADP +   P    ®   ATP + H₂O (endergonic)

Dehydration is Endergonic

 continue..............................................................................................................to part II