Question

Energy metabolism in tightly linked to high energy compounds, especially those that are phosphorylated. What are the molecular reasons that ATP can deliver so much energy? Why is group transfer of the phosphate by enzymes essential rather that simple hydrolysis?

Answer 1

SOLUTION:

Energy metabolism tightly linked to high energy compounds,especially those that are phosphorylated:

1.As high energy compound one or more high energy bond which on hydrolysis give energy atleast 7kcal/mol.They are acid anhydride bond.These are formed by the condensation of two acid molecules.

must - 0-C-Ra RI-COOH + cooH - Ra - I C-0-C-R + Ha said Anher deride I Borld. CScanned with CamScanner

This reaction showing the formation of acid anhydride bond.It is formed by the condensation of two acid molecules.

MOLECULAR REASONS THAT ATP CAN DELIVER SO MUCH ENERGY DUE TO:

1.As ATP is energy currency of the cell. It is produce in Mitrochondria.ATP is high energy compound due to the presence of two phosphoanhydride in the triphosphate.

[Phosphate - Anhydride NHO Adenine IPO P . المرحله OH OH CS (Ribase sugau)

2.ATP denotes some of its chemical energy to endergonic process such as sythesis of metabolic intermediate,transport of substance across membrance,muscle contraction.

3. The release of high amount of energy is associated with hydrolysis of ATP.

ATP4-+H2O---------->ADP3-+Pi+7.3kcal(energy) (Endergonic reaction)

Cause of ENERGY RICHNESS:

The charge separation that results from hydrolysis relieve electrostatic.

-o-p- o Rib - Adenine + n-ö 0 PO ATP4- OP-OH Ho- -o- -o- - Rib Adenine [ADPa-| -08- HPOUR so-P-ogo Htt-op-o-ė -o-Reb-Adenire Resonance Oe0- hybrid | ADP 3-

Steps shown below:

1.HYDROLYSIS: The charge separation that results from hydrolysis relieves electrostatics repulsion among the four negative charge on ATP.

2.The product inorganic phophate is stablized by formation of a resonance hybrid.

3.IONIZATION: The product ADP2- immediately ionizes releasing a proton into a medium of very low[H+].

4. The degree of solvation or hydration of product Pi and ADP relative to ATP.Which further stabilized the product relative to the reactant.

Group transfer of the phosphate by enzymes essential rather that simple hydrolysis due to:

It is essentail because transfer of phosphate to molecule from ATP by enzyme kinase.

THE HYDROLYSIS of ATP require high activation energy therefore rapid cleavage of phosphoanydride bond occur only when catalyse by an enzyme kinase.