It is a bio sensor based presentation, this presentation done by Alagu devi dpt of Bioelectronics and Biosensors at Alagappa University

1. Presentation by
Alagudevi. C

2. 


A catalyst is a substance that increases the rate at which a
chemical reaction approaches equilibrium, but is not
consumed in the process.
Catalyst affects only the rate of the reaction
Most catalysts used in industrial and research laboratories
are inorganic (often organometallic) compounds.

4. 
Catalysts can:
• Make a reaction possible under achievable conditions
• Reduce the necessity of expensive & dangerous
conditions
• Generate high yields and high product purity
• Reduce the amount of side-product and waste created

5. 
Catalysts can be divided into two main types
Catalysts
Heterogeneous
Homogeneous

6. 

This involves the use of a catalyst in a different phase from
the reactants.
Typical examples involve a solid catalyst with the reactants
as either liquids or gases.

7. 
The hydrogenation of a carbon-carbon
double bond
 The simplest example of this is the reaction between
ethylene and hydrogen in the presence of a nickel catalyst.

8. 
Ethylene molecules are adsorbed on the surface of the
nickel. The double bond between the carbon atoms breaks
and the electrons are used to bond it to the nickel surface.

9. 
Hydrogen molecules are also adsorbed on to the surface of
the nickel. When this happens, the hydrogen molecules are
broken into atoms. These can move around on the surface
of the nickel.

10. 
If a hydrogen atom diffuses close to one of the bonded
carbons, the bond between the carbon and the nickel is
replaced by one between the carbon and hydrogen.

11. 
That end of the original ethylene now breaks free of the
surface, and eventually the same thing will happen at the
other end.

12. 
As before, one of the hydrogen atoms forms a bond with
the carbon, and that end also breaks free. There is now
space on the surface of the nickel for new reactant
molecules to go through the whole process again.

13. 
The proton is the most pervasive homogeneous catalyst
because water is the most common solvent. Water forms
protons by the process of self-ionization of water In an
illustrative case, acids accelerate (catalyse)
the hydrolysis of esters:
 CH3CO2CH3 + H2O
CH3CO2H + CH3OH

14. 
Biocatalyst is a substance, for instance an enzyme or
hormone, which initiates or increases the rate of a
chemical reaction.

A biocatalyst is also known as a biochemical catalyst.

A biochemical catalyst normally an enzyme.

15. 
EXAMPLE OF AN ENZYME BIOSENSOR
◦ The most widespread biosensor today is the glucose
biosensor.
◦ It is very often used to measure the glucose
concentration in blood.
◦ There are quite a few enzymes which could be used as
glucose detectors.
◦ The following example shows the glucose enzyme
reaction with glucose oxidase.