BIOLOGY 111
CHAPTER 6:
 Life's Mainspring: An Introduction to Energy
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Life's Mainspring:
An Introduction to Energy
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6.1 Energy Is Central to Life
6.2 The Nature of Energy
6.3 How Is Energy Used by Living Things?
6.4 The Energy Dispenser: ATP
Life's Mainspring:
An Introduction to Energy
Energy Is Central to Life
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Energy always runs downhill, from higher energy to lower energy
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True with mechanical energy (spring – ‘wants to unwind’)
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True with heat (things that are hot will cool unless more energy is provided
Life's Mainspring:
An Introduction to Energy
Energy Is Central to Life
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Energy is stored in many ways!
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Living things need to have energy in the right form!
Example:
Light energy (photons) can be transformed into Glucose (Photosynthesis)
• Now Light Energy is (stored) trapped in the bonds of glucose
• Mitochondria can then convert energy in glucose bonds into ATP
Life's Mainspring:
An Introduction to Energy
•
6.1 Energy Is Central to Life
• 6.2 The Nature of Energy
• 6.3 How Is Energy Used by Living Things?
• 6.4 The Energy Dispenser: ATP
• 6.5 Efficient Energy Use in Living Things: Enzymes
• 6.6 Enzymes and the Activation Barrier
• 6.7 Regulating Enzymatic Activity
Life's Mainspring:
The Nature of Energy
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Energy is the capacity to bring about movement against an opposing force
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Forms of Energy
Chemical Energy (in chemical bonds). While in the bonds, the energy is
‘potential’ energy
1)
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Potential Energy (stored energy – person on top of a waterslide)
• This is energy (motion) that is waiting to happen
Kinetic Energy (energy in motion – person going down a waterslide)
• This energy would be transferred to the water as a splash!
Life's Mainspring:
The Study of Energy: Thermodynamics
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Thermodynamics is the study of energy
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Bioenergetics is a discipline that links biology with thermodynamics
Life's Mainspring:
The Study of Energy: Thermodynamics
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The First Law of Thermodynamics: The transformation of Energy
Energy is never created or destroyed but is only transformed
Just like sunlight is transformed into sugar, and then into ATP
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The First Law of Thermodynamics: The transformation of Energy
Life's Mainspring:
The Study of Energy: Thermodynamics
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The Second Law of Thermodynamics: The Natural Tendency Toward
Disorder
Energy transformations will spontaneously run only from greater
order to lesser order
Remember that diffusion is a response to energy from a concentrated solute to a less
concentrated solute
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The Second Law of Thermodynamics: The Natural Tendency Toward
Disorder
Life's Mainspring:
An Introduction to Energy
•
6.1 Energy Is Central to Life
• 6.2 The Nature of Energy
• 6.3 How Is Energy Used by Living Things?
• 6.4 The Energy Dispenser: ATP
• 6.5 Efficient Energy Use in Living Things: Enzymes
• 6.6 Enzymes and the Activation Barrier
• 6.7 Regulating Enzymatic Activity
Life's Mainspring:
How Is Energy Used by Living Things?
Glycogen is an ordered molecule – (a polymer constructed from
monomers)
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Isn’t this going the wrong direction? (2nd Law of Thermodynamics)
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How can this happen?
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This type of reaction is not spontaneous… it requires energy because it is taking
low energy, disorganized molecules and organizing them into higher energy
molecules
Life's Mainspring:
How Is Energy Used by Living Things?
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Glycogen is an ordered
molecule (made up of
monomers)
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Energy is required to build
glycogen (increase order)
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Energy is released when
glycogen is broken down
into glucose
Life's Mainspring:
How Is Energy Used by Living Things?
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Chemical reactions that
require energy are called
Endergonic
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Chemical reactions that
release energy are called
Exergonic
Life's Mainspring:
How Is Energy Used by Living Things?
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Where does the energy
come from for Endergonic
Reactions?
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Endergonic and Exergonic
reactions are Coupled – 1st
Law of Thermodynamics
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The Energy for Endergonic
reactions comes from Exergonic
reactions!
Life's Mainspring:
An Introduction to Energy
•
6.1 Energy Is Central to Life
• 6.2 The Nature of Energy
• 6.3 How Is Energy Used by Living Things?
• 6.4 The Energy Dispenser: ATP
• 6.5 Efficient Energy Use in Living Things: Enzymes
• 6.6 Enzymes and the Activation Barrier
• 6.7 Regulating Enzymatic Activity
Life's Mainspring:
The Energy Dispenser: ATP
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ATP (Adenosine Triphosphate) can accept relatively large amounts of energy
from a food source and then proceed to pass on this energy to a wide range
of the molecules found in the body.
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ATP is the energy source for muscle cells to contract to move your limbs, pump your heart or
to allow you to breathe
Life's Mainspring:
The Energy Dispenser: ATP
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ATP works through the addition of a
phosphate group (ADP+P  ATP)
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This stores energy in the bond between
the 2nd and 3rd phosphates
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This reaction happens inside Mitochondria.
Mitochondria use a cycle of reactions to break
the bonds in glucose and form ATP.