2. Learning Objectives:
LO 2.4 The student is able to use representations to pose scientific questions about what mechanisms and structural features allow organisms to capture, store and use free energy. [See SP 1.4, 3.1]
Ch.10
LO 2.5 The student is able to construct explanations of the mechanisms and structural features of cells that allow organisms to capture, store or use free energy. [See SP 6.2]

3. Chapter 8
Metabolism is all of an organism’s chemical processes. Macromolecules are broken down and synthesized.
The 2 types include
catabolism-a pathway that releases energy by breaking down complex molecules-polymers.
Anabolism is a pathway that consumes energy to build complicated molecules from simple ones. Ex. Photosynthesis
2. Energy is the capacity to do work. Potential energy is energy that mass contains because of its location are arrangement. Kinetic energy is the process of doing work.
Food and energy
Metabolism Energy and Life
On the platform, a diver
has more potential energy.
Diving converts potential
energy to kinetic energy.
Climbing up converts kinetic
energy of muscle movement
to potential energy.
In the water, a diver has
less potential energy.

4. Chapter 8
1. 1st law of thermodynamics- energy can be transferred and transformed but cannot be created or destroyed. Energy comes from surroundings. 2. 2nd law of thermodynamics every energy transfer or transformation makes the universe more disordered- (entropy)(S). Entropy increases.
B. Laws of thermodynamics and energy transformation
(a)
First law of thermodynamics: Energy can be transferred or transformed but
neither created nor destroyed. For
example, the chemical (potential) energy
in food will be converted to the kinetic
energy of the cheetah’s movement in (b).
Second law of thermodynamics: Every energy transfer or transformation increases
the disorder (entropy) of the universe. For example, disorder is added to the cheetah’s
surroundings in the form of heat and the small molecules that are the by-products
of metabolism.
(b)
Chemical
energy
Heat
co2
H2O +

5. Chapter 8
1.Organism live at the expense of free energy. This allows spontaneous change.
All of a systems energy is not available to do work. The energy that is available to do work is called Free energy (G). It is a product of total energy or ethalpy(H) minus Temp.(T) K-Kelvin and entropy (S)
Δ G = H – TΔS
know each.symbol
Δ G is an endergonic RXN-that requires energy
K = Celsius + 273
This helps determine if RXN is spontaneous or not.
Spontaneous RXN= Δ G<0 a negative value means it spontaneous.
C. Metabolism Energy and Life

6. Chapter 8 ∆G = –3.9 kcal/mol D. Free energy and metabolism
Reactions can be classified based upon their free energy changes
Exergonic RXN proceed w/ a net loss of free energy. They are spontaneous RXN that go down hill - Δ G is negative
Endergonic RXN requires energy that proceeds w/ a gain of free energy. The RXN is uphill. +Δ G is positive
At equilibrium Δ G = 0
Metabolic disequilibrium is necessary for life; a cell is dead at equilibrium. –Glucose VS CO2
Endergonic reaction: ∆G is positive, reaction
is not spontaneous
∆G = +3.4 kcal/mol
Glu
∆G = –7.3 kcal/mol
ATP
H2O +
NH3
ADP
NH2
Glutamic
acid
Ammonia
Glutamine
Exergonic reaction: ∆ G is negative, reaction is spontaneous P
Coupled reactions: Overall ∆G is negative;
together, reactions are spontaneous
∆G = –3.9 kcal/mol

7. Chapter 8 ∆G = –3.9 kcal/mol ∆G = +3.4 kcal/mol Glu ∆G = –7.3 kcal/mol
Endergonic reaction: ∆G is positive, reaction
is not spontaneous
∆G = +3.4 kcal/mol
Glu
∆G = –7.3 kcal/mol
ATP
H2O +
NH3
ADP
NH2
Glutamic
acid
Ammonia
Glutamine
Exergonic reaction: ∆ G is negative, reaction is spontaneous P
Coupled reactions: Overall ∆G is negative;
together, reactions are spontaneous
∆G = –3.9 kcal/mol

8. Chapter 8 E. Free energy and metabolism
Adenosine triphosphate (ATP)
H2O +
Energy
Inorganic phosphate
Adenosine diphosphate (ADP)
P i
ATP powers cellular work by coupling exergonic to endergonic RXN
ATP undergoes hydrolysis to release energy, this free energy can be used in other reactions.

9. Chapter 8 Free Energy and metabolism
ATP works by destabilizing a chemical by donating a P . This donation from ATP-adenosine tri- phosphate, releases 55kj/mol of energy.
ATP- provides energy coupling between endergonic and exergonic reactions
Cellular respiration an endergonic RXN changes ADP to ATP at 107 molecules/cell/sec

10. Chapter 8
Enzymes are specific for a particular substrate, and that specificity depends upon the enzymes three dimensional shape.
Enzymes speed up the rate of reactions.
The substrate is the substance an enzymes acts upon to make more reactive.
The location on the enzyme where the binding occurs is called the Active Site .
The catalyst leaves the RXN and is used again.
The substrate can cause the enzyme to change shape so they fit.
F. Enzymes and substrates

11. Chapter 8 Enzyme An Enzyme. Find it Substrate Active site Enzyme (a)
Enzyme- substrate
complex
Chapter 8 Enzyme

12. (a) Optimal temperature for two enzymes (b) Optimal pH for two enzymes
The optimal pH for most enzymes is 6- 8.
The optimal temp. for most enzymes is C in humans
Cofactors are small non-protein molecules are needed for proper enzyme activity. They can be inorganic metal, or organic conenzymes-most vitamins
Inhibitors are certain chemical that affect RXN. They can be irreversible if they use covalent bonds. They can be reversible if they use hydrogen bonds.
Inhibitors can be competitive or non- competitive-poisons-DDT-
Coupled reactions happen in two steps. –Ex. 1st use ATP then use the energy for a 2nd reaction.
Chapter 8
G. Factors that affect the enzyme
Optimal pH for two enzymes
Rate of reaction 20 40 60 80
100
Temperature (Cº)
(a) Optimal temperature for two enzymes
(b) Optimal pH for two enzymes pH
Optimal temperature for
typical human enzyme
enzyme of thermophilic
Optimal pH for pepsin
(stomach enzyme)
Optimal pH
for trypsin
(intestinal
enzyme) 1 2 3 4 5 6 7 8 9 10
(heat-tolerant)
bacteria

13. Chapter 8 Many enzymes are allosterically regulated
They change shape when regulatory molecules bind to specific sites, affecting function
Competitive inhibition- another binds to activation site
Non competitive-change enzyme shape
Chapter 8
H. Allosteric Activation and Inhibition
Active site available
Isoleucine used up by cell
Feedback inhibition
Isoleucine binds to allosteric site
Active site of enzyme 1 no longer binds threonine; pathway is switched off
Initial substrate (threonine)
Threonine in active site
Enzyme 1 (threonine deaminase)
Intermediate A
Intermediate B
Intermediate C
Intermediate D
Enzyme 2
Enzyme 3
Enzyme 4
Enzyme 5
End product (isoleucine)
Figure 8.21

14. Chapter 6/8 Metabolic control depends on allosteric regulation.
Allosteric regulation are binding sites on the enzyme other than the active site.
An activator on an allosteric site, stabilizes the activity.
An inhibitor on an allosteric site, stabilizes the enzymes inactivity.
Control of Metabolism

15. Chapter 6/8 Control of Metabolism
Feedback inhibition is a regulation of a metabolic pathway by its end product, which inhibits an enzyme within the pathway

16. Draw this graph then identify: G, activation energy, reactant, product, endergonic or exergonic d-b