Unit 1
Chapter 6
Biology 12
Chapter 6 Skeleton Notes:
Metabolism: Energy and Enzymes
Overview/Objectives:
6.1 Cells and the Flow of Energy
o Energy flow in ecosystems
6.2 Metabolic Reactions and Energy Transformations
o Coupling the breakdown of ATP with other reactions
o Molecules that supply the energy to drive ATP synthesis
o Function of ATP in cells
6.3 Metabolic Pathways and Enzymes
o Metabolic pathways
o Function of enzymes
o Environmental factors that affect enzyme activity
o How cells regulate enzyme activity and metabolic pathways
o Enzyme cofactors
6.1 Cells and the Flow of Energy
________________ = the capacity to do work or to change things
Why do we need energy?
 _____________________
 _____________________
 _____________________
 _____________________
 _____________________
 _____________________
Two types of energy:

_______________________________= energy of motion
o ____________________________ =type of kinetic energy
 such as _______________________________________________

_______________________________= stored energy
o _____________________________= type of potential energy
 such as ___________________________
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Unit 1
Chapter 6
Biology 12
Two Laws of Thermodynamics:
The First Law of Thermodynamics:

Energy _____________________________________________________ but it can be
changed from one form to another

Total _______________________________ = Total _______________________________
The Second Law of Thermodynamics:

Energy cannot be changed from one form to another without
______________________________________________ (often through heat)

Every energy transformation makes the world less organized and more disordered =
________________________
Examples of Entropy:
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Unit 1
Chapter 6
Biology 12
6.2 Metabolic Reactions and Energy Transformations
_________________________ = the sum total of the chemical reactions that occur in an
organism
Two types of metabolic reactions:


__________________________ = building up
__________________________= breaking down
Anabolic vs Catabolic Reactions:

_________________________________ link simple molecules
together to make complex ones. These are
________________________________ reactions.

__________________________________ break down complex
molecules into simpler ones. Some of these reactions provide the
energy for anabolic reactions. These are
________________________________ reactions.
___________________Reactions:
___________________Reactions:
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Unit 1
Chapter 6
Biology 12
Free Energy


Free Energy= the ___________________________________________________, energy
that is still “free” to do work, after a reaction has occurred

Given the symbol _______

________ = change in free energy after a reaction has occured
Free Energy (G) = _____________________________
G =__________________ - _____________________
____________________________________ =
• G is positive (+) free energy is ___________________________
• Products have more free energy than reactants
• This is the case for _____________________ reactions.
_____________________________________ =
• G is negative (–) free energy is __________________________.
• Products have less free energy than reactants
• This is the case for ________________________reactions.
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Unit 1
Chapter 6
Biology 12
ATP aka ENERGY!
_____________________________________=
• The energy molecule for cells
• Produced by mitochondria in a chemical reaction called _________________________
_____________________________________=
 As soon as ATP is formed, cells use it up!
 ATP is constantly being generated from _____________and an
______________________________ molecule Pi
Advantages of ATP as a carrier of energy:
1) Provides a common ___________________________ (It’s universal!)
2) When ATP  ADP + P, there is enough energy released
___________________________________________ (It works!)
3) When ATP is broken down, it
__________________________________________________________ to minimize
energy loss (It’s efficient!)
Structure of ATP:
 ATP is a ___________________________composed of:
 _____________________ = nitrogen containing base
 _____________________ = 5-carbon sugar
 Together= _______________________
 Three ___________________________________________
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Unit 1
Chapter 6
Biology 12
_____________________________=
• The energy released by an exergonic reaction is used to drive an endergonic reaction
• These reactions are closely tied “coupled”
There are at least 3 functions of ATP:
1) _______________________: ATP supplies the energy to synthesize macromolecules
2) _______________________: ATP supplies the energy for active transport across the cell
membrane
3) _______________________: ATP supplies the energy to contract muscles, beat cilia and
flagella, etc.
6.3 Metabolic Pathways and Enzymes
•
_____________________________ = series of linked reactions
A  B  C  D
E= _______________________
•
_____________________ = a protein molecule that functions as an organic catalyst.
________________________________________________________________
•
_____________________ = any substance that speeds up a chemical reaction without itself
______________________________________.
How do enzymes speed up chemical reactions?
•
Lowers the __________________________ needed for a reaction to occur
•
____________ = Energy required for the reaction to go from reactants  products

Much ________energy is required when an enzyme is present

The ____________ of the reaction does not change, but it does occur much
____________!
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Unit 1
Chapter 6
Biology 12
Enzyme Function = __________________________________
_____________ = Lock
_____________ = Key
 _______________ = reactant in an enzymatic reaction
E + S  ES complex  E + P
E= ___________________
S= ___________________
P= ___________________
Note: the enzyme is both reactant and product. It doesn’t get used up  enzymes are only
needed in ______________ amounts
synthesis
degradation
___________________ = site where enzyme and substrate fit together
_____________________________= the active site slightly changes shape to optimize the fit
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Unit 1
Chapter 6
Biology 12
Enzyme Names:
 Every reaction requires a specific enzyme
(… ends in “_________”)
* The enzyme that is present and active will determine the reaction
Substrate
Enzyme
Lipid
Urea
Lactose
There are 5 factors that affect enzymatic speed:
1) ________________________



Enzyme activity______________________________ as substrate concentration increases
Because ___________________________________ occur between substrate and enzyme
Until there are too many “keys” and not enough “locks”  _________________________
2) ________________________
 As temperature increases, reaction rate will _________________________
 Because higher temperature causes ______________________________________________
between enzyme and substrate
 Until the temperature becomes too high and the ______________________________________
 Enzymes have an ________________________ range and work best in it. Changes in pH change
the shape of the enzyme… Key won’t fit!
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Unit 1
Chapter 6
Biology 12
3) ________________________
 Cells regulate metabolism by ___________________________ the presence and
activity of enzymes
 Genes controlling protein synthesis and enzyme production can be turned on or off
 ________________________________ can activate enzymes
o the addition of a phosphate molecule on the enzyme makes it active
(requires kinase)
4) __________________________Occurs when the substrate is unable to bind to the active site of
the enzyme (3 ways):
a) ___________________________________- both the product and substrate can bind to
the active site  sets up a competition.
b) ___________________________________-- the product binds to a different site
(allosteric site) which causes a change of shape to the active site.
c) ___________________________________- permanently block the active site of an
enzyme  stopping activity
5) ___________________________
Many enzymes require a non-protein helper to function properly:
a) ______________________=Inorganic helpers
•
metals like copper, zinc or iron
b) ______________________== Organic helpers
•
_______________________
•
Note: deficiency in a vitamin results in a lack of coenzymes  lack of enzymatic
action *Nutrition is so important!*
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