Transcript Energy/Enzyme Lecture

NRG and Enzymes
 Definition: Ability to do
work or cause change
Types of Energy
Potential and Kinetic
Examples include:
Chemical,
Heat,
Mechanical,
Solar/Radiant,
Electrical
Newton’s Laws of Thermodynamics
1st Law: Energy is neither created nor
destroyed, it is conserved.
All energy is accounted for.
All energy in universe is same, just
different forms.
Movement of Energy through
an ecosystem
Trophic levels (Trophic levels are literally
the levels of nourishment within an
ecological system, and hence describes
how energy is transferred within food webs
and chains)
Organisms are Energy
converters
Example of Trophic/Energy Pyramid
Another energy pyramid showing loss of available
energy to heat energy
Newton’s Laws of Thermodynamics
 2nd Law: "in all energy exchanges, if no energy enters or leaves the
system, the potential energy of the state will always be less than that
of the initial state." This is also commonly referred to as entropy.
 Example: A watchspring-driven watch will run until the potential
energy in the spring is converted, and not again until energy is
reapplied to the spring to rewind it.
 Example: A car that has run out of gas will not run again until you
walk 10 miles to a gas station and refuel the car. Once the potential
energy locked in carbohydrates is converted into kinetic energy
(energy in use or motion), the organism will get no more until energy
is input again. In the process of energy transfer, some energy will
dissipate as heat. Entropy is a measure of disorder: cells are NOT
disordered and so have low entropy. The flow of energy maintains
order and life. Entropy wins when organisms cease to take in energy
and die.

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookEner1.html
Entropy
 Entropy is a measure of disorder. Entropy in the
universe is increasing as more and more energy
is converted to heat energy (energy that
dissipates and can’t be trapped as potential
energy).
 Cells are NOT disordered and so have low
entropy. The flow of energy maintains order and
life.
 Entropy wins when organisms cease to take in
energy and die.
 http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookEner1.html
Why study energy in regards to living
organisms?
 Organisms need
energy to:
 Grow
 Find a
mate/Reproduce
 Find food
 Create a habitat
 On the cellular level:
 Divide
 Repair
 Synthesize and
Catabolize
Biomolecules
 Chemical Reactions
Enzyme Characteristics
 Decrease activation
energy so chemical
reactions can take place
within cells.
 Most are proteins (what
are the monomers?)
 Lock and key hypothesis
 Function within specific
environment (pH, salt
concentration, temp.)
How enzymes work?
 Lower Activation
Energy
 Active Site
How enzymes work?
How enzymes work?
 Lock and Key Hypothesis
 Induced Fit Hypothesis
When things go wrong…change in enzyme shape
Denaturing
Mutation in the
genetic code
For example: phenylketonuria is
caused by an enzyme malfunction in
the enzyme phenylalanine
hydroxylase, which catalyses the first
step in the degradation of
phenylalanine. If this enzyme does
not function, the resulting build-up of
phenylalanine leads to mental
retardation.