Oxidation of food stuffs and redox potentials

G00D AFTERNOON

Dr. A. YOGHA PADHMA

1ST YEAR POSTGRADUATE

DEPT OF CONSERVATIVE DENTISTRY

OXIDATION OF FOOD STUFFS AND REDOX POTENTIALS

STAGES OF OXIDATION OF FOOD STUFFS

FIRST STAGE

Digestion –Gastrointestinal tract

Macromolecules

Small units

Example : Proteins Amino acids

PRIMARY METABOLISM

SECOND STAGE

Products of digestion

Absorbed Catabolized

Smaller compounds

Oxidized

Carbon dioxide

Reducing equilvalents

Generated

Mitochondria

[Final common oxidative pathway]

[Citric acid cycle]

NADH and FADH2

SECONDARY / INTERMEDIARY METABOLISM

THIRD STAGE

Reduced equivalents

NADH & FADH2

Electron transport chain/ Respiratory chain

[Energy is released]

TERTIARY METABOLISM /

INTERNAL RESPIRATION

REDOX POTENTILAS

Oxidation reduction potential

Electron transfer potential

Quantitative measure of the tendency of a redox pair to lose or gain electrons

Oxidation – Loss of electrons

Reduction –Gain in electrons

Substance – Exists in reduced & oxidized state – REDOX COUPLE

POSITIVE & NEGATIVE REDOX POTENTIAL

Substance

Low affinity for electrons than hydrogen - NEGATIVE

Higher affinity for electrons than hydrogen - POSITIVE

Strong reducing agent – NADH [ NRP – 0.32 V]Strong oxidising agent – OXYGEN [PRP +0.82 V]

ATP

ADENOSINE TRIPHOSPHATE

Adenine

Ribose

Triphosphate moiety

High energy compound – 2 phosphoanhydridebonds –Triphosphate units

ENERGY CURRENCY OF THE CELL

SYNTHESIS OF ATP

OXIDATIVE PHOSPHORYLATION:

Major source –Aerobic organisms

Linked to mitochondrial ETC

SUBSTRATE LEVEL PHOSPHORYLATION:

Directly synthesized

High energy compounds – Phosphoenolpyruvate & 1,3 bisphosphoglycerates & SuccinylCoA –Transfer high energy phosphate - ATP