1. 3/2 Daily Catalyst Pg. 86 Energy
1. The Tasmanian devil suffers from a form of facial cancer (F). The frequency of the cancer in a population is 37%. Determine the allele of the f gene.
2. Thylakoids contain a large amount of ___________________.
3. List the products of the light reaction and the dark reaction.

2. 1. The Tasmanian devil suffers from a form of facial cancer (F)
1. The Tasmanian devil suffers from a form of facial cancer (F). The frequency of the cancer in a population is 37%. Determine the allele of the f gene.
P2= 37% (.37)
P= .61
p+q=1
.61+q=1
q= .39

3. 3/2 Daily Catalyst Pg. 86 Energy
2. Thylakoids contain a large amount of ___________________.
Chlorophyll (in the photosystems)
3. List the products of the light reaction and the dark reaction.
O2, NADPH, and ATP
Glucose

4. 3/2 Agenda Pg. 86 Energy Daily Catalyst Class Business Reading quiz
Energy notes
Intro to enzymes
Review quiz #21

5. 3/2 Reading Quiz 1. An enzyme is what type of molecule?
2. Define activation energy.
3. What is the unstable condition molecules are in?
4. When bonds are broken, __________ is released.

6. An Introduction to Metabolism
Chapter 8
An Introduction to Metabolism

7. Key Concepts
An organism’s metabolism transforms matter and energy, subject to the laws of thermodynamics
The free-energy change of a reaction tells us whether the reaction occurs spontaneously

8. Some organisms convert energy to light, as in bioluminescence
Video Clip

9. Concept 8.1: An organism’s metabolism transforms matter and energy, subject to the laws of thermodynamics
So let’s talk about the law of thermodynamics and metabolism.

10. Key Point #1: Metabolism
The the sum of an organism’s chemical reactions that take place in a cell
interactions between molecules

11. Metabolic Pathways A metabolic pathway:
Begins with a specific molecule (reactant) and ends with a product
Catalyzed by a specific enzyme
Catalyzed?
To speed up a reaction.
Enzyme 1
Enzyme 2
Enzyme 3 A B C D
Reaction 1
Reaction 2
Reaction 3
Starting molecule
Product

12. Key Point #2: Catabolic pathways
Break down complex molecules into simpler compounds
Release energy
Some pathways break down molecules

13. Key Point #3: Anabolic pathways
Build complicated molecules from simpler ones
Consume energy

14. So what is energy? Key Point #4: Energy
Definition: Is the capacity to cause change
To do work
Exists in various forms
Energy cannot be created nor destroyed

15. Types of energy Kinetic energy Potential energy
Is the energy associated with motion
Potential energy
Is stored in the location of matter
Includes chemical energy stored in molecular structure (ATP)

16. Energy can be converted from one form to another
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.
Figure 8.2
We are considered energy transformers because the chemical was from the plants we ate that made their enregy through photosynthesis.

17. An example of energy conversion
The chemical (potential) energy
in food will be converted to the kinetic
energy of the cheetah’s movement.
Chemical
energy
What happens to the er

18. Exergonic Key Point #5: Exergonic/exothermic reactions
Release of free energy
Spontaneous
Reactants
Products
Energy
Progress of the reaction
Amount of
energy
released (∆G <0)
Free energy

19. Key Point #6: Endergonic/endothermic reactions
Absorbs free energy from its surroundings
nonspontaneous
Energy
Products
Amount of
energy
released (∆G>0)
Reactants
Progress of the reaction
Free energy

20. Exergonic reactions power the endergonic

21. A cell does three main kinds of work:
Concept 8.3: ATP powers cellular work by coupling exergonic reactions to endergonic reactions
A cell does three main kinds of work:
Mechanical- movement
Transport-transportation
Chemical- synthesis of polymers

22. The Structure and Hydrolysis of ATP
ATP (adenosine triphosphate)
Cell’s energy
Figure 8.8 O
CH2 H OH N C HC
NH2
Adenine
Ribose
Phosphate groups - CH

23. Energy coupling Pairing reactions together
Is a key feature in the way cells manage their energy resources to do this work

24. Energy is released from ATP When the terminal phosphate bond is broken
Potential energy (chemical energy)
When the terminal phosphate bond is broken P
Adenosine triphosphate (ATP)
H2O +
Energy
Inorganic phosphate
Adenosine diphosphate (ADP)
P i

25. ATP hydrolysis can be coupled to other reactions
Endergonic reaction: ∆G is positive, reaction
is not spontaneous
∆G = +3.4 kcal/mol
Glu
∆G = 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
Figure 8.10
The breaking down of ATP or removing a phosphate group.

26. How ATP Performs Work ATP drives endergonic reactions
By phosphorylation, transferring a phosphate to other molecules
The molecule gets phosphorylated

27. The three types of cellular work are powered by the hydrolysis of ATP
(c) Chemical work: ATP phosphorylates key reactants P
Membrane
protein
Motor protein
P i
Protein moved
(a) Mechanical work: ATP phosphorylates motor proteins
ATP
(b) Transport work: ATP phosphorylates transport proteins
Solute
transported
Glu
NH3
NH2 +
Reactants: Glutamic acid
and ammonia
Product (glutamine)
made
ADP

28. Quiz #21
Directions: Review your assigned question. Be ready to share out the correct answer with your classmates and tell us why the right answer is what it is.
Time: 5 minutes
Noise: 1 (with a partner)

29. Question #
Reviewer 1
Daquine 2
Kordell 3
Travia 4 5
Yennifer 6
Teresa 7
Tiana 8
Bristin 9
Kiandria 10
Taylor 11
Anthony 12
Quinshelle 13
Tiffany 14
Daniel 15
John 16
Annie

31. Concept 8.4: Enzymes speed up metabolic reactions by lowering energy barriers
A catalyst
Is a chemical agent that speeds up a reaction without being consumed by the reaction

32. An enzyme
A protein that acts like a catalyst

33. How do enzymes speed up a reaction?

34. The Activation Barrier
Energy is needed to break and make bonds. This is what we call a reaction.

35. The activation energy, EA
Is the initial amount of energy needed to start a reaction
Heat

36. The energy profile for an exergonic reaction
Free energy
Progress of the reaction
∆G < O EA A B C D
Reactants
Transition state
Products

37. I mentioned heat before as the energy source
I mentioned heat before as the energy source. Why is heat not always the best option in a cell?

38. How Enzymes Lower the EA Barrier

39. The effect of enzymes on reaction rate
Progress of the reaction
Products
Course of
reaction
without
enzyme
Reactants
with enzyme EA
EA with
is lower
∆G is unaffected
by enzyme
Free energy
Figure 8.15

41. Substrate Specificity of Enzymes
Enzyme binds to the substrate.
enzyme-substrate complex

42. Can the substrate bind anywhere?
The active site
Is the region on the enzyme where the substrate binds
Figure 8.16
Substate
Active site
Enzyme
(a)

43. Induced fit of a substrate
Once met, the active site changes shape so that the substrate fits even better.
Figure 8.16
(b)
Enzyme- substrate
complex

44. Reusable

45. The catalytic cycle of an enzyme
Substrates
Products
Enzyme
Enzyme-substrate
complex
1 Substrates enter active site; enzyme
changes shape so its active site
embraces the substrates (induced fit).
2 Substrates held in
active site by weak
interactions, such as
hydrogen bonds and
ionic bonds.
3 Active site (and R groups of
its amino acids) can lower EA
and speed up a reaction by
• acting as a template for
substrate orientation,
• stressing the substrates
and stabilizing the
transition state,
• providing a favorable
microenvironment,
• participating directly in the
catalytic reaction.
4 Substrates are
Converted into
Products.
5 Products are
Released.
6 Active site
Is available for
two new substrate
Mole.
Figure 8.17

46. Enzymes help the substrate reach the transition state by straining substrate bonds so they break easily.

47. The active site can lower an EA barrier by
Orienting substrates correctly
Straining substrate bonds
Providing a favorable microenvironment
Covalently bonding to the substrate

48. Enzyme activity
Enzyme activity also relies on the substrate concentration.
Increase [substrate] = increase E-S complex
Eventually the solution will be saturated and more enzymes will be needed.

49. Effects of Local Conditions on Enzyme Activity
The activity of an enzyme
Is affected by general environmental factors

50. Effects of Temperature and pH
Each enzyme
Has an optimal temperature in which it can function
Figure 8.18
Optimal temperature for
enzyme of thermophilic
Rate of reaction 20 40 80
100
Temperature (Cº)
(a) Optimal temperature for two enzymes
typical human enzyme
(heat-tolerant)
bacteria

51. Has an optimal pH in which it can function
Figure 8.18
Rate of reaction
(b) Optimal pH for two enzymes
Optimal pH for pepsin
(stomach enzyme)
Optimal pH
for trypsin
(intestinal
enzyme) 1 2 3 4 5 6 7 8 9

52. Cofactors Cofactors Coenzymes Are nonprotein enzyme helpers
Are organic cofactors

53. Enzyme Inhibitors Competitive inhibitors
Bind to the active site of an enzyme, competing with the substrate
Figure 8.19
(b) Competitive inhibition
A competitive
inhibitor mimics the
substrate, competing
for the active site.
Competitive
inhibitor
A substrate can
bind normally to the
active site of an
enzyme.
Substrate
Active site
Enzyme
(a) Normal binding

54. Noncompetitive inhibitors
Bind to another part of an enzyme, changing the function
Figure 8.19
A noncompetitive
inhibitor binds to the
enzyme away from
the active site, altering
the conformation of
the enzyme so that its
active site no longer
functions.
Noncompetitive inhibitor
(c) Noncompetitive inhibition

55. Concept 8.5: Regulation of enzyme activity helps control metabolism
A cell’s metabolic pathways
Must be tightly regulated

56. Allosteric Regulation of Enzymes
Is the term used to describe any case in which a protein’s function at one site is affected by binding of a regulatory molecule at another site
Regulatory molecules bind to specific sites (allosteric sites) and change the shape of the protein.
Inhibit or stimulate

57. Allosteric Activation and Inhibition
Many enzymes are allosterically regulated

58. They change shape when regulatory molecules bind to specific sites, affecting function
Stabilized inactive form
Allosteric activater stabilizes active from
Allosteric enyzme with four subunits
Active site (one of four)
Regulatory site (one of four)
Active form
Activator
Stabilized active form
Allosteric activater stabilizes active form
Inhibitor
Inactive form
Non- functional active site
(a) Allosteric activators and inhibitors. In the cell, activators and inhibitors dissociate when at low concentrations. The enzyme can then oscillate again.
Oscillation
Figure 8.20

59. Cooperativity
Is a form of allosteric regulation that can amplify enzyme activity
Figure 8.20
Binding of one substrate molecule to active site of one subunit locks all subunits in active conformation.
Substrate
Inactive form
Stabilized active form
(b) Cooperativity: another type of allosteric activation. Note that the inactive form shown on the left oscillates back and forth with the active form when the active form is not stabilized by substrate.

60. Feedback Inhibition In feedback inhibition
The end product of a metabolic pathway shuts down the pathway

61. Feedback inhibition Figure 8.21 Initial substrate (threonine)
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

62. Specific Localization of Enzymes Within the Cell
Within the cell, enzymes may be
Grouped into complexes
Incorporated into membranes

63. Contained inside organelles
1 µm
Mitochondria,
sites of cellular respiraion
Figure 8.22