This document provides an overview of chemioenergetics and oxidative phosphorylation. It discusses how mitochondria convert food into ATP through a series of redox reactions known as the electron transport chain located on the inner mitochondrial membrane. These reactions establish a proton gradient that is used by ATP synthase to phosphorylate ADP, producing ATP. Specifically, it describes (1) the structure and function of the electron transport chain complexes and enzymes, (2) how the chemiosmotic theory and proton gradient underlie ATP production, and (3) the binding change mechanism of ATP synthesis by ATP synthase. The document concludes that oxidative phosphorylation is the key process by which mitochondria generate cellular energy in the form of ATP.

1. CHEMOBIOENERGETICS
PRESENTED BY:AJISHAS
BABU
PRESENTED DATE: /12/2022

2. CONTENTS
• INTRODUCTION
• CHEMOBIOENERGETICS
• MITOCHONDRIALSTRUCTURE
• TYPESOFREACTION
• ELECTRONTRANSPORTPROCESSES
• ELECTRONTRANSPORTCHAIN
• OXIDATIVEPHOSPHORYLATION
• CHEMIOSMOTICTHEORY
• BINDINGCHANGEMECHANISMOFATPSYNTHESIS
• CONCLUSION
• REFERENCES

3. • BIOENERGETICS IS A FIELD IN BIOCHEMISTRY AND CELL BIOLOGY THAT CONCERNS ENERGY
FLOW THROUGH LIVING SYSTEMS.
• BIOENERGETICS CAN ALSO BE DEFINED AS THE STUDY OF ENERGY RELATIONSHIPS AND
ENERGY TRANSFORMATIONS AND TRANSDUCTIONS IN LIVING ORGANISMS.
• FATHER OF BIOENERGETICS:-ALEXANDER LOWEN, M.D. (1910 – 2008)
INTRODUCTION

5. • AEROBIC RESPIRATION (OXIDATIVE PHOSPHORYLATION) IS CARRIED OUT IN MITOCHONDRION, WHERE THE FOOD STUFFS
(CARBOHYDRATE, PROTEIN AND FATS) ARE CONVERTED INTO ENERGY PROVIDING MOLECULES, ATP, VIA KREB CYCLE, AND
THE ELECTRON TRANSPORT CHAIN COUPLED TO ATP SYNTHESIS BY OXIDATIVE PHOSPHORYLATION. THE PRIMARY
FUNCTION OF MITOCHONDRIA IS TO SUPPLY THE CELL WITH ATP MOLECULES DURING OXIDATIVE PHOSPHORYLATION - 36
MOLECULES OF ATP FOR EVERY MOLECULE OF GLUCOSE OXIDIZED. THE GENERAL SCHEME OF THE REACTION THAT TAKE
PLACE IN MITOCHONDRIA IS AS REPRESENT IN THE FIGURE :-
CHEMOBIOENERGETICS

6. MITOCHONDRIAL STRUCTURE
• THE MITOCHONDRION CONSISTS
OF AN OUTER MEMBRANE, AN
INNER MEMBRANE, SEPARATED
FROM THE OUTER MEMBRANE BY
AN INTERMEMBERANE REGION
AND A MATRIX REGION,
SURROUNDING BY AN INNER
MEMBRANE AND INNER-MEMBER
PARTICLES(KNOBS) PROTRUDING
INTO THE MATRIX REGION.

7. • THE BIOENERGETIC REACTION IN THE
MITOCHONDRION TAKE PLACE IN THE MATRIX
REGION AND IN THE INNER MEMBRANE
SURROUNDING IT. MOST OF THE SOLUBLE ENZYMES
OF THE MITOCHONDRION ARE FOUND IN THE
MATRIX, INCLUDING THE ENZYMES REQUIRED FOR
ELECTRON TRANSPORT AND OXIDATIVE
PHOSPHORYLATION(F0-F1 ATPASE).THE CLUSTER OF
KNOBS ON INNER MEMBRANES , PROTRUDING
INTO THE MATRIX ARE F1- PARTICLES OF F0F1-
ATPASE. THE LOCATION OF ENZYMES IN THE MATRIX
AND INNER MEMBRANE OF THE MITOCHONDRION
IN THE FIGURE

9. Types of Reactions
ENDERGONIC RECATIONS
• Endergonic reactions may also be
called
an unfavorable reaction or
nonspontaneous reaction. The
reaction
requires more energy than you get
from it.
• Endergonic reactions absorb
energy from
their surroundings.
EXERGONIC REACTIONS
• An exergonic reaction may be
called a
spontaneous reaction or a

10. ELECTRON TRANSPORT PROCESS
•
• The oxidation process in mitochondrion(in the matrix) begins when
pyruvate and fatty acids are converted into acetyl coenzyme A which
is the starting product of citric acid cycle. In the citric acid cycle, the
acetyl group of acetyle co A is oxidized to produce end products
NADH and FADH2, which are in turn the starting product for the
electron transport chain redox reactions in the mitochondrial inner
membrane, that transport electrons down the respiratory chain to
reduce molecular oxygen(O2) to water.

12. • The oxidative and phosphorylation reactions in the mitochondrial inner
membrane can be functionally compartmentalized into five enzyme
Complex groups. Four of these are respiratory chain complexes, 1to4 and
5th Complex, ATP synthase is coupled to the electron- transport chain.
Each of the complexes of the electron transport chain has increasing
affinity for electrons and electrons are thus transported vectorially down
the electron transport chain to O2, which has the greatest affinity for
electron. The 5th Complex, ATP synthase, catalyzes synthesis as well as
hydrolysis of ATP.

13. RESPIRATORY CHAIN
ELECTRON TRANSPORT CHAIN IN MITOCHONDRIA
A COMPLEX COULD BE A DEFINED AS A STRUCTURE THAT COMPRISES A WEAK PROTEIN, MOLECULE OR ATOM THAT
IS
WEAKLY CONNECTED TO A PROTEIN.
THE PLASMA MEMBRANE OF PROKARYOTES COMPRISES MULTI COPIES OF THE ELECTRON TRANSPORT CHAIN.
• COMPLEX 1- NADH-Q OXIDOREDUCTASE: IT COMPRISES ENZYMES CONSISTING OF IRON SULPHUR AND FMN.
HERE TWO
ELECTRONS ARE CARRIED OUT TO THE FIRST COMPLEX ABROAD NADH. FMN IS DERIVED FROM VITAMIN B2.

15. • Complex 2- succinate -Q reductase:
FADH2 that is not past through
Complex 1 is received directly from
complex 2. The first and the second
the complexes are connected to third
Complex through compound
ubiquinone (Q). The Q molecule is
soluble in water and moves freely in
the hydrophobic core of the
membrane. In this phase, an
electron is delivered directly to the
electron proteins chain. The number
of ATP obtained at the stage is
directly proportional to the number of
protons that are pumped across the
inner membrane of the mitochondria.

17. •Complex 3- cytochrome c
reductase : the third complex is
comprise of Fe_S protein,
cytochrome B and cytochrome C
protein. cytochrome protein
consists of the Heme group.
Complex 3 is responsible for
pumping Protons across the
membrane. It also passes
electrons to the cytochrome C
where it is transported to the 4th
Complex of enzymes and
proteins. Here, Q is the electron
donor and Cytochrome C is the
electron acceptor.

18. •Complex 4 – cytochrome C
oxidise the 4th complex is
comprised of cytochrome c, a
and a3. There are two heme
groups where each of them is
present in cytochromes c and a3.
The cytochromes are responsible
for holding oxygen molecules
between copper and iron until the
oxygen content is reduced
completely. In this place, the
reduced oxygen picks two
hydrogen ions from the
surrounding environment to
make a water.

19. OXIDOREDUCTASE)
II- COMPLEX II: (SUCCINATE
DEHYDROGENASE)
COQ- COENZYME Q (UBIQUINONE)
III -COMPLEX III: (CYTOCHROME BC1
COMPLEX)
IV -COMPLEX IV: (CYTOCHROME C OXIDASE)

23. OXIDATIVE
PHOSPHORYLATION
•OXIDATIVE PHOSPHORYLATION IS THE
PROCESS IN WHICH ATP IS FORMED AS A
RESULT OF THE TRANSFER OF ELECTRONS
FROM NADH OR FADH2 TO O2 BY A SERIES
OF ELECTRON CARRIERS.
•THIS PROCESS, WHICH TAKES PLACE IN
MITOCHONDRIA, IS THE MAJOR SOURCE OF
ATP IN AEROBIC ORGANISMS.
FOR EXAMPLE, OXIDATIVE
PHOSPHORYLATION GENERATES 26 OF THE
30 MOLECULES OF ATP THAT ARE FORMED
WHEN GLUCOSE IS COMPLETELY OXIDIZED
TO CO2 AND H2O.

24. • Oxidative phosphorylation is the
culmination of a series of energy
transformations that are called
cellular respiration or simply
respiration in their entirety.
• First, carbon fuels are oxidized
in the citric acid cycle to yield
electrons with high transfer
potential.
•Then, this electron-motive force
is converted into a proton-motive
force and, finally, the proton-
motive force is converted into
phosphoryl transfer potential.

26. CHEMIOSMOTIC
HYPOTHESIS
•In 1961, Peter Mitchell
postulated the Chemiosmotic
hypothesis. It explains the
mechanism of ATP synthesis
within chloroplast during
photosynthesis.
• During the photochemical
phase or light reaction, ATP and
NADP are generated.
• These are the key components

27. THEORY
•According to this theory, molecules like glucose are metabolized to develop
acetyl CoA in the form of an intermediate that is energy-rich.
•The proper oxidation of acetyl CoA occurs in the mitochondrial matrix and is
combined to the reduced form of a carrier molecule namely FAD and NAD.
•The carriers then supply electrons to the transport chain of the electron in
the inner membrane of mitochondria, which further supply them to different
other proteins present in the ETC.
•The energy present in the electrons is basically used to pump out protons
from the matrix in the inner mitochondrial membrane. It is used for energy
storage in the form of a transmembrane electrochemical gradient.
•The protons return to the inner membrane by the ATP enzyme synthase. The
proton-flow travels into the matrix of mitochondria through ATP synthase,
which gets a good amount of energy for the ADP to integrate with inorganic
phosphate to produce ATP.

29. ATP SYNTHASE
• The ATP synthase (or F1F0 ATPase
and also referred to as complex V)
uses the free energy of an
electrochemical gradient of protons
(or sodium ions) generated by the
respiratory chain to synthesize ATP.
• Human mitochondrial (mt) ATP
synthase, or complex V consists of
two functional domains: F1, situated
in the mitochondrial matrix, and F0,
located in the inner mitochondrial
membrane.
• The ATP synthesis takes place at the

30. • F1 (ATPASE) IS THE SPHERICAL PROTEIN EXTENDING
INTO THE MATRIX.
• CONTAINS 5 DIFFERENT SUBUNITS AND THE
CATALYTIC SITE FOR ATP SYNTHESIS.
• THE COMPLEX CONTAINS SITES THAT CHANGE IN
THEIR AFFINITY FOR ATP AS PROTONS FLOW
THROUGH THE COMPLEX.
• THIS PROTON FLOW ALLOWS THE ATPASE TO REVERSE
DIRECTION AND SYNTHESIZE ATP.
• F0 IS THE INTEGRAL OLIGOMER ATTACHED TO F1 VIA
A STALK.
• THE F0 CONTAINS THE PROTON CHANNEL.
• THE STALK REGULATES PROTON FLOW AND ATP
SYNTHESIS, CONTAINS AN F1INHIBITOR AND IS THE
OLIGOMYCIN SENSITIVE REGION.

31. https://youtu.be/yM493qHmCmg

33. CONCLUSIO
N
• OXIDATIVE PHOSPHORYLATION IS CARRIED OUT IN MITOCHONDRION, WHERE THE FOOD STUFFS ARE
CONVERTED INTO ENERGY PROVIDING MOLECULES, ATP.
• THE BIOENERGETIC REACTION IN THE MITOCHONDRION TAKE PLACE IN THE MATRIX REGION AND IN
THE INNER MEMBRANE SURROUNDING IT.
• 2 TYPES OF REACTIONS :-ENDERGONIC RECATIONS AND EXERGONIC REACTION.
• THE ELECTRON TRANSPORT CHAIN IS A SERIES OF FOUR PROTEIN COMPLEXES THAT COUPLE REDOX
REACTIONS, CREATING AN ELECTROCHEMICAL GRADIENT THAT LEADS TO THE CREATION OF ATP IN A
COMPLETE SYSTEM NAMED OXIDATIVE PHOSPHORYLATION. IT OCCURS IN MITOCHONDRIA IN BOTH
CELLULAR RESPIRATION AND PHOTOSYNTHESIS.
• COMPLEX 1- NADH-Q OXIDOREDUCTASE
• Q AND COMPLEX 2- SUCCINATE-Q REDUCTASE:
• COMPLEX 3- CYTOCHROME C REDUCTASE:
• COMPLEX 4- CYTOCHROME C OXIDASE

34. •OXIDATIVE PHOSPHORYLATION IS THE PROCESS IN WHICH ATP IS FORMED AS A RESULT OF THE
TRANSFER OF ELECTRONS FROM NADH OR FADH2 TO O2 BY A SERIES OF ELECTRON CARRIERS.
• CHEMIOSMOTIC THEORY :-PETER MITCHELL POSTULATED THE CHEMIOSMOTIC HYPOTHESIS. IT
EXPLAINS THE MECHANISM OF ATP SYNTHESIS WITHIN CHLOROPLAST DURING PHOTOSYNTHESIS.
•ATP SYNTHASE IS A PROTEIN THAT CATALYZES THE FORMATION OF THE ENERGY STORAGE MOLECULE
ADENOSINE TRIPHOSPHATE USING ADENOSINE DIPHOSPHATE AND INORGANIC PHOSPHATE.
•BINDINGCHANGEMECHANISMOFATPSYNTHESIS:-
ACCORDING TO BOYER’S BINDING CHANGE MECHANISM FOR ATP SYNTHESIS, THE THREE CATALYTIC
SITES ON THE ENZYME BIND ADP AND PHOSPHATE IN SEQUENCE AND THEN UNDERGO A
CONFORMATIONAL CHANGE SO AS TO MAKE A TIGHTLY BOUND ATP. THE SITES THEN CHANGE
CONFORMATION AGAIN TO RELEASE THE ATP.

35. REFERENC
ES
1. P NARAYANAN, 2007, ESSENTIALS OF BIOPHYSICS, NEW AGE INTERNATIONAL
PUBLISHERS NEW DELHI.
2. S N PANDEY, 2005 PLANT PHYSIOLOGY 4TH EDITION VIKAS PUBLISHING HOUSE
PVT LTD. NEW DELHI.
3. DR PRANAB KUMAR BANERJEE,2008, INTRODUCTION TO BIOPHYSICS, S.
CHAND AND COMPANY PVT. LTD. NEW DELHI .
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LTD. NEW DELHI.
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36. THANKYOU