2. General concepts
Metabolism: The process of catabolism and metabolism
Catabolism: the process by which a living organism obtains its energy and raw materials from nutrients.
Anabolism: the process by which energy and raw materials are used to build macromolecules and cellular
structures (Biosynthesis).
Reduction and Oxidation:
An atom becomes more reduced when it undergoes a chemical reaction in which it :
Gain electrons
By bonding to less electronegative
And often this occur when atom bond to hydrogen.
An atom become oxidized when it undergoes a chemical reaction in which
Loses electrons
By bonding to more electronegative
And often this occur when atom bond to hydrogen.
3. • In metabolic pathways, we are often concerned with
oxidation or reduction of carbon.
•Reduced form of carbon (e.g. hydrocarbon, methane)
carry a great deal of potential chemical energy stored in
their bond.
•Oxidized form of carbon (e.g. ketones, aldehydes) carry a
little potential of chemical energy stored in their bonds.
• Reduction and Oxidation always occur together. In a
Reduction and Oxidation reaction, one substance get
reduced other get oxidized. Thing that get oxidized is
called electron Donor & Thing that get reduced is called
electron acceptor.
4. • Metabolic reaction take place in step wise fashion in which atoms
of the raw material rearranged Often one time , until the formation of
the final product takes place.
• Each step requires its own enzymes.
• The sequence of enzymatically catalyzed steps from a starting raw
material to end products is called an enzymatic pathway (for
metabolic pathway).
• ATP: A currency of energy for many cellular reactions
• Adenosine Triphosphate.
• Energy give :7.5kcal/mol
5. Respiration
Features:
Pyruvic acid oxidized completely to CO2.
The final electron acceptor is inorganic substance.
NADH is Oxidized from NAD: it is essential to continue
glycolytic pathways.
O2 may or may not required.
•Aerobic Respiration: O2 is final electron acceptor.
•Anaerobic Respiration: an substance usually inorganic other
than O2 the acceptor ( e.g. Nitrates, nitrites, sulfate).
Up to 36/glucose molecule ATP are formed.
6. • Stages of Respiration
• Preliminary reactions and Krebs cycle ( Citric acid cycle)
• Respiratory electron transport
7. Glycolytic pathways
Features of Glycolytic pathways
Partial oxidation of glucose to form pyruvic acid,
A small amount of ATP is made,
A small amount of NAD is reduced to NADH
Glycolytic pathways found different bacteria
Embden-Meyerhoff-Parnas pathway
Classic glycolysis found in all organism
Hexose monophosphate pathway
also found in most organism
responsible for synthesis of nucleotide
Enter-Doudoroff pathway
found in Pseudomonas and related genra
Phosphoketolase pathway
found in Bifidobacerium and Leuconostoc
8. • Energy generating patterns:
After sugar are obtained, They are major source of life.
Breakdown of sugar (Catabolism) different ways
• Aerobic respiration
• Anaerobic respiration
• Fermentation
Aerobic respiration
• Most efficient way to extract energy from glucose.
• Process: Glycolysis, Kreb cycle, Electron transport chain
• Glycolysis: several glycolytic pathways.
• The most common one:
• Glucose….> pyruvic acid + 2NADH + 2ATP
