Glycolysis breaks down glucose to produce energy through a process that occurs in the cytoplasm and does not require oxygen. It produces pyruvate, ATP, NADH, and water. The Krebs cycle is a series of reactions in the mitochondrial matrix where acetyl-CoA is oxidized to produce carbon dioxide and reduce coenzymes to generate ATP. The electron transport chain is a collection of proteins on the inner mitochondrial membrane where electrons pass through in redox reactions, releasing energy to form a proton gradient used to make ATP via chemiosmosis.

1. GLYCOLYSIS
Glycolysis is the process in
which glucose is broken down
to produce energy. It
produces two molecules of
pyruvate, ATP, NADH and
water. The process takes
place in the cytoplasm of a
cell and does not require
oxygen. It occurs in both
aerobic and anaerobic
organisms.

2. KREB’S CYCLE
The Krebs cycle or TCA cycle
(tricarboxylic acid cycle) or
Citric acid cycle is a series
of enzyme catalyzed reactions
occurring in the mitochondrial
matrix, where acetyl-CoA is
oxidized to form carbon
dioxide and coenzymes are
reduced, which generate ATP in
the electron transport chain.

3. ELECTRO TRANSPORT CHAIN
The ETC is a collection of
proteins bound to the inner
mitochondrial membrane and
organic molecules, which
electrons pass through in a
series of redox reactions,
and release energy. The
energy released forms a
proton gradient, which is
used in chemiosmosis to
make a large amount of ATP
by the protein ATP-synthase.

4. CHEMIOSMOSIS
ATP SYNTHESIS

5. CHEMIOSMOSIS refers to the process of moving ions
(e.g. protons) to the other side of a biological
membrane, and as a result, an electrochemical gradient
is generated. This can then be used to drive ATP
synthesis. The gradient also incites the ions to return
passively with the help of the proteins embedded in the
membrane. By “passively”, it means that the ions will
move from an area of higher concentration to an area of
lower concentration.
INTRODUCTION

6. Peter D. Mitchell
The theory of Chemiosmosis was proposed by a man named
Peter D. Mitchell (1920- 992). He is a British biochemist.
In the 1960s, he knew about the phenomenon of membrane
potential in which the inner side of the membrane being
negative relative to its environment. ATP was also already
recognized at that time as the cell’s major energy currency.
However, how living organisms produce ATP biologically
was not well established.

7. 02 04
This process is similar to OSMOSIS where water
molecules move passively. In the case of
chemiosmosis, though, it involves the ions moving
across the membrane; in osmosis, it is the water
molecules. Nevertheless, both processes require a
gradient.
BIOLOGICAL GRADIENTS

8. OSMOSIS
OSMOSIS (Greek for push) is the
net movement of water across a
semipermeable membrane.
Across this membrane, water will
tend to move from an area of high
concentration to an area of low
concentration.

9. The mitochondria have long been known as the organelles
responsible for ATP synthesis. How these organelles generate ATP
was initially not clear and was presumed to relate to substrate-level
phosphorylation (as what happens in glycolysis).

10. Where does
chemiosmosis
occur?

11. CHEMIOSMOSIS in CHLOROPLAST

12. In chloroplast, chemiosmosis occurs in the thylakoid. This
membrane system has its own transport chain and ATP
synthases. One of the major differences between chemiosmosis
in mitochondria and in chloroplasts is the source of energy. In
mitochondria, the high-energy electrons are extracted from the
food molecule (from redox reaction) whereas in chloroplast the
source is from the photons captured from the light source. The
proton (H+) gradient forms from the H+ ions accumulating in the
thylakoid compartment (i.e. the space inside the thylakoid).

13. CHEMIOSMOSIS in PROKARYOTIC CELL

14. Mercury Mars Neptune
Mars is actually a
very cold place
It’s very far away
from the Sun
It’s the closest
planet to the Sun
The hydrogen ions (protons) move across the biological
membrane via the ATP synthase (a transport protein) when a
proton gradient forms on the other side of the membrane.
The proton gradient forms when the hydrogen ions
accumulate as they are forcibly moved to the other side
during the electron transport and redox reactions. As more
hydrogen ions are on the other side they will move back to
the cell move by crossing the membrane through the ATP
synthase. As they flow through, energy is released and used
to convert ADP to ATP through phosphorylation.

15. Two Key Components of Chemiosmosis
An electron transport chain (ETC) - a series of
membrane-bound molecules that passes
electrons from an electron donor to a final
electron acceptor, creating a proton gradient at
the same time.
ATP synthase - an enzyme that uses the proton
gradient to catalyze the synthesis of ATP.

16. CHEMEOISMOSIS MODEL