PLANT PHYSIOLOGY IMPORTANT TOPIC

1. OXIDATIVE
PHOSPHORYLATION

2. KALYAN POST GRADUATE COLLEGE
BHILAI NAGAR
OXIDATIVE PHOSPHORYLATION
DEPARTMENT BOTANY
OF
SESSION – (2023-2024)
P R E S E N T A T I O N O N
SUBMITTED BY:
SHUBHAM NAGWANSHI
MSc. 2nd Sem
GUIDED BY:-
RAKESH SIR

3. SYNOPSIS OF
OXIDATIVE PHOSPHORYLATION
1. INTRODUCTION
2. DEFINITION
3. TYPES TO SYNTHESIZEATP
Oxidativeand SubstrateLevelPhosphorylation
4. MECHANISMOF OP
ChemicalCoupling hypothesis & Chemiosmotic theory
5. CONCLUSION
6. REFERENCE

4. Introduction
• During transfer of electrons through
the ETC energy is produced.
• This energy is coupled to the formation
of ATP from ADP.
• By an enzyme F0F1 ATPase.
Oxidative phosphorylation is a
cellular process that harnesses the
reduction of oxygen to generate
high-energy phosphate bonds in the
form of adenosine triphosphate
(ATP).

5. Definition
 Mitochondria are the site of
oxidative phosphorylation
in eukaryotes.
 The synthesis of ATP from ADP
(phosphorylation), that occurs
when NADH and FADH2 are
oxidized by through electron
transport chain (respiratory
chain).
 Oxidation coupled with
phosphorylation is called
Oxidative phosphorylation.

6. Cell Membrane or Cytoplasmic
Membrane are the site of
oxidative phosphorylation in
prokaryotes.
Mitochondria are the site of
oxidative phosphorylation in
eukaryotes.

7. THERE IS TWO WAYS TO
SYNTHESIZE ATP
Oxidative
Phosphorylation
Substrate level
phosphorylation
direct transfer the phosphate from
chemical intermediate
( also called substrate ) to ADP or GDP
forming ATP or GTP, dependent of
electron transfer chain.
the phosphorylation of ADP to ATP
coupled to electron transfer
ATP ADP + Pi

8. Example of
Substrate level phosphorylation
Glycolysis Phosphoglycerate
kinase
1,3-bisphosphoglycerate
ADP
ATP
3-phosphoglycerate

9. Phosphoenolpyruvate
ADP
ATP
TCA CYCLE
GLYCOLYSIS Pyruvate kinase
Pyruvate
Succinyl COA
succinate
GDP
GTP
succinyl CoA
synthetase

10. MECHANISM OF O.P.
Several hypotheses have been put
forth to explain the process of
oxidative phosphorylation.
Chemical coupling
hypothesis
Chemiosmotic
theory

11. CHEMICAL COUPLING HYPOTHESIS
 This hypothesis was put forth by Edward Slater (1953)
 According to this hypothesis, during the course of electron transfer in
respiratory chain, a series of phosphorylated high-energy intermediates
are first pro used which are utilized for the synthesis of ATP.
 These reactions are believed to be analogous to the substrate level
phosphorylation that occurs in glycolysis or citric acid cycle.
 However, this hypothesis lacks experimental evidence.

12. MECHANISM OF OXIDATIVE
PHOSPHORYLATION
Peter Mitchell
1920-1992
CHEMIOSMOTIC
THEORY

13. CHEMIOSMOTIC THEORY
 This hypothesis is the most accepted theory.
 Proposed by Peter Mitchell in 1961.
 To explains how the transport of electrons through the
respiratory chain (ETC) is effectively utilized to produce ATP
from ADP + Pi.
Nobel Prize, in 1978

14. There are three basic principles of the theory.
1. Pumping of protons via electron carrier proteins
2. Generation of electrochemical potential.
i. Membrane potential ii.Proton gradient (chemical potential)
3. Electron transport flow back to matrix through ATPase.

15. PUMPING OF PROTONS VIA ETC
The inner mitochondrial membrane, is impermeable to
protons & hydroxyl ions.
The transport of electrons through ETC is coupled with the
translocation of protons (H+) across the inner mitochondrial
membrane from the matrix to the intermembrane space.
This results in an electrochemical or proton gradient.

18. CHEMIOSMOTIC
THEORY

19. OR
The transfer of two
electrons from NADH+ h+
to 02 is accompanied by
the outward pumping of 10
h+.
Complex I and complex III
pumps 4 protons each.
Complex IV pumps 2 protons
To inter-membranous space.
10 protons are pumped by
the electron transport chain.
10 protons are pumped out per NADH.
1. 4 must flow in to produce 1 ATP.
2. The proton-based p/O ratio is 2.5 for NADH
as the electron donor and 1.5 (6/4) for succinate.

20. ATP generation (old and new values)

21. CONCLUSION
In summary:
The oxidative Phosphorylation process is as follow
 Electron transport down the respiratory chain from NADH or
FADH2.
 Complex I , III, IV Cause protons be pumped out Of the
mitochondrial matrix into the intermembrane space
 The pumping out of H+ generates a higher conc. Of H+ and an
electrical potential , thus an electrochemical proton gradient is
formed.
 The flow back into the mitochondrial matrix through ATP
synthase and the electrochemical proton gradient drives ATP
synthesis

22. REFERENCE
PLANT PHYSIOLOGY BY ROUS AND SALISBURY
PLANT PHYSIOLOGY BY TAIZ AND ZEIGER
www.sciencedirect.com
www.quora.com