Metabolism

1
Metabolism

• Energy Transformations

2
Metabolism

• The capacity to acquire use energy to ensure
  survival.
• Cellular activities, Maintenance, Growth
• Building Accumulating
• Breaking Apart Eliminating
• Involves
• ENERGY
• CHEMICAL REACTIONS

3
ENERGY

• The ability to do workto cause change.
• Variety of forms
• Light, Heat, Mechanical, Chemical, Electrical
• 2 Main States
• POTENTIAL
• Stored energy, with the potential to do
  something.
• KINETIC
• Energy of motion in the process of doing
  something.

4
Energy Transformations

• Potential Kinetic Potential Kinetic
• Governed by Laws of Thermodynamics.
• 1st Law of Thermodynamics
• (Conservation of Energy)
• 2nd Law of Thermodynamics
• (Entropy)

5
1st Law of Thermodynamics

• Energy is neither created nor destroyed.
• The amount of energy in the universe is constant.
• BUT, energy can change FORMS

SUN
STARCH
FOOD
MOVEMENT
HEAT
COAL
ELECTRIC
6
2nd Law of Thermodynamics

• Energy is generally transformed from HIGH QUALITY
  to LOW QUALITY forms.
• This leads to less and less organization.
• Entropy is a measure of disorganization.

SUN
STARCH
FOOD
MOVEMENT
HEAT
COAL
ELECTRIC
7
Life has Organization

• Opposite of Entropy, but
• How? Why?
• Life requires a constant re-supply of high
  quality energy from
• Ultimately from our nearest star, the sun.

What if the sun disappeared?
8
Organization requires Energy

• Energy is stored (by living things) in chemical
  formin chemical bonds.
• When bonds are broken, energy is liberated.
• Chemical Reactions!
• Loss of energy
• Gain of energy

EXERGONIC
ENDERGONIC
9
Chemical Reactions

• Endergonic
• Exergonic
• Reversible
• Coupled

10
Changes in Free Energy (?G)

• A measure of the portion of a systems energy
  that can be kinetic (do work).
• Spontaneous chemical reactions involve a loss of
  energy from the initial state.
• ?G Gfinal Ginitial
• Spontaneous chemical reactions have a negative
  free energy (?Glt0).
• Reactions tend toward stability and equilibrium.
• Pp. 145-147

11
Metabolic Pathways

• SERIES of chemical reactions.
• Biosynthetic (Anabolic) building pathways which
  consume energy.
• Degradative (Catabolic) degrading pathways
  which release energy.
• Enzymes are responsible for each reaction.
• (well come back to these later)

12
ATP

• Adenosine Triphosphate
• Energy Carrier the energy currency

13
ATP

• Photosynthesis
• Sunlight Chemical Energy
• ATP
• Cellular Respiration
• -Chemical Energy Work
• ATP

14
ATP Hydrolysis
15
ATP

• Drives other endergonic reactions
• Phosphorylation of an intermediate molecule (A or
  B) makes it more reactive.

16
ATP

• Regeneration of ATP Phosphorylation.

17
ATP Phosphorylation

• ATP is primed.
• 1. Substrate-Level Phosphorylation.
• 2. Chemiosmotic Phosphorylation.

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