metabolism, anabolism and catabolism.ppt

metabolism

1. Metabolism: An Introduction
Totality of an organism’s processes
•Molecular interactions make this an emergent
property
•Concerned with managing cellular material and
energy
•Anabolic Pathways
•Catabolic Pathways
•These Anabolic/Catabolic reactions can be
coupled so that energy released from a catabolic
rx can drive an anabolic rx.

2. Catabolic Pathways
RELEASE ENERGY by breaking down complex
molecules to simpler ones

3. ANABOLIC PATHWAYS
CONSUME ENERGY to build complicated
molecules from simpler ones

4. Organisms Transform Energy
•Energy: Capacity to do work
•Kinetic Energy: Energy in the process of doing
work (energy of motion) ex.:Light,Thermal.
•Potential Energy: Energy of position (energy due
to arrangement or location). Ex.:Rock on hill,
chemical energy
•ENERGY CAN BE TRANSFORMED FROM
ONE FORM TO ANOTHER. Ex: Gas-motion

5. Energy Transformations and
Thermodynamics
•Thermodynamics: The study of energy
transformations
•First Law of Thermodynamics: Energy can’t be
created or destroyed, only transferred or
transformed
•Second Law of Thermodynamics: Every energy
transfer increases ENTROPY
•Entropy: Quantitative measure of disorder
(proportional to randomness)

6. More Thermodynamics Vocab.
Closed System:
Collection of matter
being studied which is
isolated from the
surroundings
Open System: A system
in which energy can
be transferred from
the system and its
surroundings

7. ENTROPY
•The entropy of a system may DECREASE, but
the entropy of the system plus its surroundings
must always INCREASE.
Animals:
•Maintain highly ordered structure at the expense
of their surroundings
•Take in complex high energy molecules as food
and extract energy in order to create and maintain
order
•Return simple low energy molecules and heat to
surroundings

8. FREE ENERGY
The amount of energy that is available to do work
•Free Energy:G
•Total Energy or Enthalpy: H
•Temperature in Kelvin Degrees: T
•Entropy: S
Free energy is the difference between the total
energy and the energy NOT available to do work.
Gibbs-Heimholtz equation:
G=H-ST

9. Significance of Free Energy
•Indicates a maximum amount of a system’s
energy which is available to do work
•Indicates whether a reaction will occur
spontaneously or not
•A spontaneous reaction is one that will occur
without any additional energy
•The change in Free energy of a system
DECREASES in a spontaneous reaction.
•A decrease in enthalpy (or total energy) or a n
increase in entropy reduce the free energy, and
make a spontaneous more likely
•Increased Temperature favors spontaneity
•These reactions tend toward a more stable state

10. Free Energy and Equilibrium
There is a relationship between chemical
equilibrium and free energy change
•As the reaction approaches equilibrium, the
free energy decreases
•As a reaction is pushed away from
equilibrium, free energy increases.
•AT equilibrium, there is no net change in
the system (0 change in free energy)

11. Free Energy and Metabolism
EXERGONIC
REACTIONS: A reaction
with a net LOSS of free
energy
•Spontaneous
•The change in Free
energy (downhill) is the
max. amount of work the
Rx can do
•Products have less free
energy than rectants
ENDERGONIC
REACTIONS: An energy
requiring reaction that
occurs with a net GAIN
of free energy
•Absorbs energy
•Products store more free
energy
•Non-spontaneous
•The change in free energy
(uphill) is the min.
amount of energy
required to drive the rx

12. What the………..(O.K., here’s some examples)
•Burning (oxidation) of one mole of
glucose: EXERGONIC and releases 686
Kcal/mol. Actually Free energy is said to
be NEGATIVE or-686Kcal/mol.
•Production of 1 mole of glucose is
ENDERGONIC and requires the energy
input of +686Kcal/mole

13. Energy Units
•Joule(J): .239 calorie
•Kilojoule(kJ): 1000J or .239 Kcal
•Calorie(cal): 4.184J

14. METABOLIC
DISEQUILIBRIUM
•At equilibrium the system can’t do work:
Change of free energy is 0.
•Necessity of life: A cell at total equilibrium
is dead
•These reversible reactions are pulled one
way or the other because the products of 1
become the reactants for another