Transcript Thermodynamics - Madison Public Schools

The Flow of Energy In Living
Systems
Unit 3: Bioenergetics
Honors Biology
Monkemeier
Thermodynamics
 Thermodynamics is the branch of
science that relates to energy
changes (conversions from one
form to another)
 The Laws of Thermodynamics help
to explain energy and energy
changes.
Bioenergetics
 Bioenergetics is the field of
biochemistry that concerns energy
flow through living systems.
 All activities of living organisms
involve flow of energy through living
systems as well as changes in
energy.
What is Energy?
 Energy is defined
as the capacity to
do work.
 We think of energy
as existing in two
states: Kinetic
energy and
potential energy.
Energy
 Kinetic energy is
energy of motion.
Moving objects
perform work by
causing other matter
to move.
 Potential energy is
stored energy. Objects
that are not moving
but have the capacity
to do so posses
potential energy.
The Many Forms of Energy
 Energy can take
many forms:
mechanical energy
(kinetic and
potential), heat,
sound, electric
current, light, or
radioactive
radiation.
Heat
 Because it can exist in so many
forms, energy can be measured in
many ways.
 The most convenient measure is in
terms of heat, because ALL other
forms of energy can be converted into
heat.
 The term THERMODYNAMICS means
“heat changes”.
Measuring HEAT (Energy)
 The unit of heat most commonly employed
in biological systems is the kilocalorie (kcal)
 1 kcal = 1,000 calories
 1 calorie = the amount of heat required to
raise 1 gram of water one degree Celsius
 Another unit that can be used is the joule.
It takes 4.18 joules of energy to raise 1
gram of water one degree Celsius.
Organisms
 Organisms require
a constant supply
of energy.
 The ultimate
source of energy
for living systems
is the SUN!
Photosynthesis
 Autotrophs (Producers) use the process of
photosynthesis to convert radiant
electromagnetic energy into chemical
energy.
 Photosynthesis converts carbon from an
inorganic form (CO2) to an organic form, in
the process of storing energy from the SUN
as potential energy in the covalent bonds
between atoms of sugar molecules.
Oxidation – Reduction Reactions
 Energy flows through living systems
(organisms) as a series of oxidation and
reduction reactions.
 High energy electrons are stripped from
one molecule (oxidizing it) and given to
another molecule (reducing it).
 Oxidation – reduction reactions ALWAYS
occur together.
 Oxidation – reduction reactions (REDOX
reactions) play a key role in the flow of
energy through biological systems.
Oxidation / Reduction
Putting it all Together!
 Photosynthesis converts radiant
electromagnetic energy into chemical
energy.
 Chemical energy is energy between the
atoms of a molecule.
 Cellular respiration is the process that
converts chemical energy into free energy.
 Free energy is energy that is available to do
work immediately.
 Free Energy is stored and released in a
molecule of ATP.
Photosynthesis and Cellular
Respiration
Bioenergetics and Thermodynamics
 Bioenergetics studies the flow of
energy through living systems
(organisms).
 As energy flows through living
systems and is converted from one
form to another, it is governed by the
Laws of Thermodynamics.
 The next PPT will relate to the Laws
of Thermodynamics.
Next PPT
 The Laws of Thermodynamics