ATP

1. ATP Production
Prepared By:
Simranjeet Kaur
Asssistanat Professor Pharmacology
PCTE Group of Institutions

2.  Living cells require energy from outside sources
 Energy flows into an ecosystem as sunlight and leaves as heat
 Photosynthesis generates O2 and organic molecules, which are
used in cellular respiration
 Cells use chemical energy stored in organic molecules to
regenerate ATP, which powers work

3. Adenosine Tri-Phosphate (ATP)
 ATP is the energy unit of the cell.
 ATP is composed of an Adeno. Group, a sugar group and three
phosphates.
 ATP is easily recycled.
 The cell converts Adenosine Di-Phosphate (ADP) into ATP by
the addition of a phosphate.

4. Fig. 9-2
Light
energy
ECOSYSTEM
Photosynthesis
in chloroplasts
CO2 + H2O
Cellular respiration
in mitochondria
Organic
molecules
+ O2
ATP powers most cellular work
Heat
energy
ATP

5. The Principle of Redox
 Chemical reactions that transfer electrons between reactants are
called oxidation-reduction reactions, or redox reactions
• In oxidation, a substance loses electrons, or is oxidized
 In reduction, a substance gains electrons, or is reduced (the amount
of positive charge is reduced)

6. Redox Reactions: Oxidation and
Reduction
 The transfer of electrons during chemical reactions releases
energy stored in organic molecules
 This released energy is ultimately used to synthesize ATP

7. ATP powers cellular work by coupling
exergonic reactions to endergonic reactions
 A cell does three main kinds of work:
 Chemical
 Transport
 Mechanical
 To do work, cells manage energy resources by energy coupling,
the use of an exergonic process to drive an endergonic one
 Most energy coupling in cells is mediated by ATP

9. ATP
• ATP (adenosine triphosphate) is the cell’s energy shuttle
• ATP is composed of:
– ribose (a sugar)
– adenine (a nitrogenous base)
– Three phosphate groups

10. Fig. 8-8
Phosphate groups
Ribose
Adenine

11. • The bonds between the phosphate groups of ATP’s tail can be
broken by hydrolysis
• Energy is released from ATP when the terminal phosphate bond
is broken
• This Third Phosphate bond contains LOTS of Energy
• This release of energy comes from the chemical change to a state
of lower free energy, not from the phosphate bonds themselves

12. Fig. 8-9
Inorganic phosphate
Energy
Adenosine triphosphate (ATP)
Adenosine diphosphate (ADP)
P P
P P P
P ++
H2O
i

13.  The three types of cellular work are:
 mechanical
 transport
 chemical
 Each is powered by the hydrolysis of ATP
 In the cell, the energy from the exergonic reaction of ATP
hydrolysis can be used to drive an endergonic reaction

14. Fig. 8-11
(b) Mechanical work: ATP binds noncovalently
to motor proteins, then is hydrolyzed
Membrane protein
P i
ADP
+
P
Solute Solute transported
P i
Vesicle Cytoskeletal track
Motor protein Protein moved
(a) Transport work: ATP phosphorylates
transport proteins
ATP
ATP

15. Phosphorylation
 ATP drives endergonic reactions by phosphorylation,
transferring a phosphate group to some other molecule, such
as a reactant
 The recipient molecule is now phosphorylated

16. Phosphorylation
 The process of Phosphorylation converts a relatively low
energy compound (ADP) into a higher energy compound
(ATP)
 ADP (Adenosine Di-Phosphate)- Contains an Adenosine, a
ribose group, and two Phosphate groups.

17. Fig. 8-12
P iADP +
Energy from
catabolism (exergonic,
energy-releasing
processes)
Energy for cellular
work (endergonic,
energy-consuming
processes)
ATP + H2O

18. The ATP Cycle
 ATP can be produced from existing ADP molecules
 A phosphate is added to ADP at the mitochondria.
 Requires ATP synthase - A protein complex in the
mitochondria that acts a molecular mill and converts ADP into
ATP.

19. Fig. 9-UN7
INTER-
MEMBRANE
SPACE
H+
ATP
synthase
ATPADP + P i
H+
MITO-
CHONDRIAL
MATRIX

20. The Regeneration of ATP
 ATP is a renewable resource that is regenerated by addition of a
phosphate group to adenosine diphosphate (ADP).
 Requires ATP synthase and H ions (from water.)
• The energy to phosphorylate ADP comes from catabolic
reactions in the cell.
• The chemical potential energy temporarily stored in ATP can
then be used to drive most cellular work.