Bioenergetics is the study of energy in living systems and organisms. ATP (adenosine triphosphate) is the main energy carrier in cells. It contains high-energy phosphate bonds that are broken to release energy for cellular work through the hydrolysis of ATP. This exergonic reaction is coupled to endergonic cellular processes like biosynthesis through phosphorylation, transferring a phosphate group and restoring the chemical bonds in ATP.

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BIOENERGETICSBIOENERGETICS
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What is Bioenergetics?
The study of
energyenergy in livingliving
systemssystems
(environments)
and the
organismsorganisms
(plants and
animals) that
utilize them
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Energy
 Required by
all organisms
 May be
Kinetic or
Potential
energy
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Kinetic Energy
 Energy of
Motion
 Heat and
light energy
are
examples
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Potential Energy
 EnergyEnergy ofof
positionposition
 IncludesIncludes
energyenergy
stored instored in
chemicalchemical
bondsbonds
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Two Types of
Energy Reactions
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Endergonic Reactions
 Chemical reactionChemical reaction that
requires a net input of
energyenergy.
 PhotosynthesisPhotosynthesis
6CO2 + 6H2O → C6H12O6 + 6O2
SUN
photonsphotons
Light
Energy
(glucose)(glucose)
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Exergonic Reactions
 Chemical reactionsChemical reactions that
releases energyreleases energy
 Cellular Respiration
C6H12O6 + 6O2 → 6CO2 + 6H2O+ ATP
(glucose)(glucose)
EnergyEnergy
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Metabolic Reactions
of Cells
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What is Metabolism?
 The sum totalsum total
of the
chemicalchemical
activitiesactivities of
all cellscells.
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Two Types of Metabolism
 AnabolicAnabolic
PathwaysPathways
 CatabolicCatabolic
PathwaysPathways
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Anabolic PathwayAnabolic Pathway
 Metabolic reactions,Metabolic reactions, which
consume energyconsume energy (endergonic),(endergonic), to
buildbuild complicated molecules from
simpler compounds.
 PhotosynthesisPhotosynthesis
6CO2 + 6H2O → C6H12O6 + 6O2
SUN
lightlight
energyenergy
(glucose)(glucose)
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Catabolic PathwayCatabolic Pathway
 Metabolic reactionsMetabolic reactions which releaserelease
energyenergy (exergonic)(exergonic) by breakingbreaking
downdown complex molecules in simpler
compounds
 Cellular RespirationCellular Respiration
C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP
(glucose)(glucose)
energy
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Cellular Energy -Cellular Energy -
ATPATP
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ATPATP
 Components:Components:
1. adenine: nitrogenous base1. adenine: nitrogenous base
2. ribose:2. ribose: five carbon sugarfive carbon sugar
3.phosphate group: chain of 33.phosphate group: chain of 3
riboseribose
adenineadenine
P P P
phosphate groupphosphate group
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Adenosine TriphosphateAdenosine Triphosphate
 ThreeThree
phosphatephosphate
groups-groups-(two(two
with highwith high
energy bondsenergy bonds
 Last phosphateLast phosphate
group (POgroup (PO44))
contains thecontains the
MOST energyMOST energy
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Breaking the Bonds of ATPBreaking the Bonds of ATP
 Process is called
phosphorylationphosphorylation
 Occurs continually
in cells
 Enzyme ATP-aseATP-ase
can weaken &
break last POlast PO44
bondbond releasing
energy & free PO4
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How does ATP work ?How does ATP work ?
 Organisms use enzymesenzymes to
break down energy-richenergy-rich
glucoseglucose to release its
potential energy
 This energy is trapped and
stored in the form of
adenosine triphosphate(ATP)adenosine triphosphate(ATP)
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How Much ATP Do Cells Use?How Much ATP Do Cells Use?
 It is estimated
that each celleach cell
will generate
and consume
approximately
10,000,00010,000,000
molecules ofmolecules of
ATPATP per secondper second
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Coupled Reaction - ATPCoupled Reaction - ATP
 The exergonicexergonic
hydrolysishydrolysis of ATPATP
is coupled with
the endergonicendergonic
dehydrationdehydration
processprocess by
transferringtransferring a
phosphate groupphosphate group
to another
molecule.
HH22OO
HH22OO
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Hydrolysis ofHydrolysis of ATPATP
ATP + H2O → ADP + P
(exergonic)
HydrolysisHydrolysis
(add water)(add water)
P P P
Adenosine triphosphate (ATP)Adenosine triphosphate (ATP)
P P P++
Adenosine diphosphate (ADP)Adenosine diphosphate (ADP)
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Hyrolysis is ExergonicHyrolysis is Exergonic
EnergyEnergy
UsedUsed
byby
CellsCells
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Dehydration ofDehydration of ATPATP
ADP +ADP + PP →→ ATPATP ++ HH22OO
(endergonic(endergonic)
P P P
Adenosine triphosphate (ATP)Adenosine triphosphate (ATP)
P P P++
Adenosine diphosphate (ADP)Adenosine diphosphate (ADP)
DehydrationDehydration
(Remove H(Remove H22OO
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Dehydration is EndergonicDehydration is Endergonic
EnergyEnergy
isis
restoredrestored
inin
ChemicalChemical
BondsBonds
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ReviewReview
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How many high energyHow many high energy
phosphate bonds does ATPphosphate bonds does ATP
have?have?
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Which is true of photosyntheis?Which is true of photosyntheis?
AnabolicAnabolic oror CatabolicCatabolic
ExergonicExergonic OrOr EndergonicEndergonic
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The breakdown of ATP isThe breakdown of ATP is
due to:due to:
DehydrationDehydration oror HydrolysisHydrolysis
HH22O addedO added oror HH22O removedO removed
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Which Reactions are oftenWhich Reactions are often
Coupled in OrganismsCoupled in Organisms
HydrolysisHydrolysis oror DehydrationDehydration
AnabolismAnabolism or Catabolismor Catabolism
EndergonicEndergonic oror ExergonicExergonic
BOTHBOTH
BOTHBOTH
BOTHBOTH
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Ready for the test?Ready for the test?
If not, review andIf not, review and
try again!!!try again!!!
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