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Lee, Thonylet E.
Mabinta, Dianne
Melad, Maria Fe

What is Bioenergetics?
The study of energy in living systems
(environments) and the organisms
(plants and animals) that utilize
them.
Energy
 Required by all organisms
 May be Kinetic or Potential energy

Kinetic Energy
Energy of
Motion
Heat and
light energy
are
examples

Potential Energy
Energy of
position
Includes
energy
stored in
chemical
bonds

Bioenergetics
 Bioenergetics is the part
of biochemistry concerned with the energy
involved in making and breaking of chemical
bonds in the molecules found in
biological organisms.
 Growth, development and metabolism are some
of the central phenomena in the study of
biological organisms. The role of energy is
fundamental to such biological processes. The
ability to harness energy from a variety of
metabolic pathways is a property of all living
organisms. Life is dependent on energy
transformations; living organisms survive because
of exchange of energy within and without.

Bioenergetics
In a living organism, chemical bonds are
broken and made as part of the
exchange and transformation of energy.
Energy is available for work (such as
mechanical work) or for other processes
(such as chemical synthesis
and anabolic processes in growth), when
weak bonds are broken and stronger
bonds are made. The production of
stronger bonds allows release of usable
energy.

Bioenergetics
It is the quantitative study of the
energy transductions that occur in
living cells and of the nature and
function of the chemical
processes underlying these
transductions.

Law of Thermodynamics
The laws of thermodynamics
are important unifying
principles of biology. These
principles govern the chemical
processes (metabolism) in all
biological organisms.

 The First Law of Thermodynamics, also know as
the law of conservation of energy, states that
energy can neither be created nor destroyed.
It may change from one form to another, but
the energy in a closed system remains
constant.
 In any physical or chemical change, the total
amount of energy in the universe remains
constant, although the form of energy may
change.

 The Second Law of Thermodynamics
states that when energy is transferred, law
of entropy, there will be less energy
available at the end of the transfer
process than at the beginning. Due to
entropy, which is the measure of disorder
in a closed system, all of the available
energy will not be useful to the organism.
Entropy increases as energy is transferred.
 In all natural processes, the entropy of the
universe increases.

ATP Production
Before cells can use the energy
of sunlight or energy /calories
stored in carbohydrates, they
must transfer the energy to
molecules of ATP.

ATP Production
ATP is composed of adenine,
ribose, and three phosphate
groups.
ATP transfers energy to many
different chemical reactions;
almost all metabolic pathways
directly or indirectly run on
energy supplied by ATP.

ATP Production
In human cells, cellular respiration
releases energy from energy-rich
organic molecules and changes
ADP into ATP.
Aerobic respiration is the main ATP-
producing pathway
Anaerobic respiration produces
much less ATP (because no oxygen is
involved) and can only be used for
short periods of time, such as in
vigorous muscle exercise.

ATP Production
It provides a common energy
currency that can be used in many
different types of reactions,
When ATP becomes ADP+P, the
amount of energy released is just
about enough for the biological
purposes, and so little energy is
wasted.
ATP breakdown is coupled to
endergonic reactions in such a
way that it minimizes energy loss.

ATP Production
 Initial Breakdown of Glucose
 Glycolysis reactions occur in the
cytoplasm (liquid stuff outside the
nucleus) and results in the breakdown
of glucose to pyruvate; small amounts
of ATP are generated.
 Glucose is first phosphorylated in
energy-requiring steps then split to
form two molecules of PGAL

ATP Production
 By substrate-level phosphorylation, four
ATP are produced; but because two ATP
were used previously, there is a net gain of
only two ATP.
 Enzymes remove H+ and electrons from
PGAL to change NAD to NADH (which is
used later in oxidative phosphorylation).
The end products of glycolysis are: two
pyruvates, two ATP (net gain), and two
NADH for each glucose molecule
degraded.

ATP Production
The actual ATP synthesis is
accomplished when H ions
that have been pumped out
of the inner mitochondrial
compartment flow back
through a channel protein
called ATP synthase.

ATP Production
Oxygen joins with the "spent"
electrons and H+ to yield
water.
The production of ATP is
completely dependent on the
supply of oxygen that withdraws
the electrons at the end of the
transport systems.

ATP Production
 The ADP/ATP Cycle
 The ADP/ATP cycle
is a method for
renewing the supply
of ATP that is
constantly being
used up in the cell.
 Energy input
couples inorganic
phosphate to ADP
to form energized
ATP.

Alternative Energy Sources
Carbohydrates
Lipids
Proteins

ATP Production
 Chemical Work- supplies energy needed
to synthesize macromolecules that make
up the cell.
 Transport Work- supplies the energy
needed to pump substances across the
plasma membrane.
 Mechanical Work- supplies the energy
needed to permit muscle to contract,
cilia and flagella to beat, chromosomes.

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Bioenergetics (biochemistry)

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