Chapter 8 Metabolism & Enzymes
-
Upload
emerson-nieves -
Category
Documents
-
view
56 -
download
2
description
Transcript of Chapter 8 Metabolism & Enzymes
![Page 1: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/1.jpg)
![Page 2: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/2.jpg)
![Page 3: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/3.jpg)
What is life?
![Page 4: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/4.jpg)
![Page 5: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/5.jpg)
![Page 6: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/6.jpg)
Figure 6.1 The complexity of metabolism
![Page 7: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/7.jpg)
-series of steps
-enzyme directed
-enzyme managed
-the management of material and energy resources
Catabolic Anabolic
![Page 8: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/8.jpg)
– forming bonds between molecules• dehydration synthesis• anabolic reactions
– breaking bonds between molecules• hydrolysis• catabolic reactions
![Page 9: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/9.jpg)
RELEASES ENERGY
COUPLED RXN’s
USES/STORES ENERGY
![Page 10: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/10.jpg)
![Page 11: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/11.jpg)
![Page 12: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/12.jpg)
![Page 13: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/13.jpg)
![Page 14: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/14.jpg)
THERMODYNAMICS
the study of energy transformations
Closed system? Open?
(Bioenergetics)
![Page 15: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/15.jpg)
1st LAW OF THERMODYNAMICS:
Energy can be changed but not created or destroyed
Energy of universe is constant
A qualitative change - not quantitative
![Page 16: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/16.jpg)
![Page 17: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/17.jpg)
2ND LAW OF THERMO.:
Entropy of the universe is constantly
increasing
![Page 18: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/18.jpg)
Which of these happens spontaneously?
![Page 19: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/19.jpg)
DEFINE ENTROPY-
randomness or disorder
WHAT CAUSES IT?-
energy transfers or transformations
![Page 20: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/20.jpg)
WHAT IS FREE ENERGY?
energy available for work
WHAT IS WORK?
any change!
![Page 21: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/21.jpg)
![Page 22: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/22.jpg)
![Page 23: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/23.jpg)
![Page 24: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/24.jpg)
![Page 25: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/25.jpg)
Order as a characteristic of life
![Page 26: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/26.jpg)
![Page 27: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/27.jpg)
![Page 28: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/28.jpg)
Organisms require energy to live
– Sources of energy?Coupling exergonic reactions (releasing energy)
with endergonic reactions (needing energy)
+ + energy
+ + energy
![Page 29: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/29.jpg)
1st + 2nd = Quantity of energy is conserved but
not the quality
Fate of all energy is to end up as heat energy - not
available for work
![Page 30: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/30.jpg)
Organisms are open systems that exchange energy and materials with their
surroundings.
They create ordered structures using energy that flows into environment as light.
They take in ordered structures and create less ordered ones and release heat.
Living systems then increase entropy.
Complex organisms developed from simpler ones. Entropy?
![Page 31: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/31.jpg)
REACTIONS!
SPONTANEOUS
OR
NOT?
With or without outside help?
![Page 32: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/32.jpg)
Kinetic and potential energy: dam
![Page 33: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/33.jpg)
The relationship of free energy to stability, work capacity, and spontaneous change
![Page 34: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/34.jpg)
Disequilibrium and work in closed and open systems
![Page 35: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/35.jpg)
When a spontaneous process occurs in a system, stability of
the system is increased.
Unstable systems tend to change to become more stable.
![Page 36: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/36.jpg)
More free energyLess stable
Greater work capacity
In a spontaneous change
•free energy decreases (ΔG<0)
•system becomes more stable
•released free energy can be used to do work
More free energyLess stable
Greater work capacity
![Page 37: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/37.jpg)
Energy changes in exergonic and endergonic reactions
![Page 38: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/38.jpg)
EXERGONIC REACTIONS:
• ENERGY RELEASING REACTIONS
• PROCEEDS WITH A NET LOSS OF FREE ENERGY
• DOWNHILL; SPONTANEOUS
• NEGATIVE FREE ENERGY
![Page 39: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/39.jpg)
ENDERGONIC REACTIONS-
• ENERGY REQUIRING
• PROCEEDS WITH A NET GAIN OF FREE ENERGY
• UPHILL; NONSPONTANEOUS
• POSITIVE FREE ENERGY
![Page 40: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/40.jpg)
G = free energy
H = total energy
S = entropy
T = ‘C + 273 = K
G = H - TS
![Page 41: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/41.jpg)
G = H - T S
G = free energy
G = Gfinal state - Ginitial state
H = total energy (enthalpy)
T = degrees Kelvin
S = entropy
![Page 42: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/42.jpg)
Disequilibrium and work in closed and open systems
![Page 43: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/43.jpg)
Spontaneous??
Systems that are-
High free energy &/or low entropy
Unstable
Highly ordered
![Page 44: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/44.jpg)
G < 0
![Page 45: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/45.jpg)
Nature runs downhill!
To occur spontaneously, the system must either
give up energy (a decrease in H), give up order (an increase in S)
or both. G < 0
![Page 46: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/46.jpg)
![Page 47: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/47.jpg)
![Page 48: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/48.jpg)
The structure and hydrolysis of ATP
![Page 49: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/49.jpg)
ATP
![Page 50: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/50.jpg)
Energy coupling by phosphate transfer
![Page 51: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/51.jpg)
The ATP cycle
![Page 52: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/52.jpg)
![Page 53: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/53.jpg)
Interesting Enzymes•Mars Rovers search for traces of enzymes
•PKU test - phenylketonuria
•meat tenderizer, cleansers
•heart attack indicator
•improve dough quality in bread
•improve clarity in beer and liquors
![Page 54: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/54.jpg)
•environmental cleanup and biotech
•10,000 to 20,000 daltons in size
•125-3000 amino acid units
•10176 to 109020 possible combinations
•only 10103 molecules in universe
•age of universe is 1017 seconds old
•<1040 enzyme codons have been read since life began
![Page 55: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/55.jpg)
Catalase can digest 5 million hydrogen peroxide molecules per minute
1 ounce of pepsin per 4000 lbs of egg white in a few hours-- would take 10 to 20 tons of acid for 24-48 hours at high temp
![Page 56: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/56.jpg)
![Page 57: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/57.jpg)
![Page 58: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/58.jpg)
![Page 59: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/59.jpg)
ΔG = change in free energy = ability to do work
![Page 60: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/60.jpg)
Chemical reaction & energy
• Some reactions release energy– Exergonic
• Digesting polymers
• Hydrolysis = catabolism
• Some reactions require input of energy– Endergonic
• Building polymers
• Dehydration synthesis = anabolic
![Page 61: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/61.jpg)
G = H - T S G = ( -) or (< 0 ) G = ( +) or (> 0 ) spontaneous/ downhill nonspontaneousexergonic endergoniccatabolic anabolicRespiration Photosynthesisenergy released energy storedexothermic endothermicLow G High GHigh S Low S
initial final
final initial s
T = absolute temperature KH = change in total bond energy of reactants and products in a systemG = free energy S = change in entropy = disorder or randomness
assume as "0" then ΔG = H Free energy = total potential energyincrease entropy = decrease in free energy
or increase temperature = increase in entropy
![Page 62: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/62.jpg)
![Page 63: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/63.jpg)
PROTEIN KINASES
Enzymes that catalyze phosphorylation
PHOSPHATASES
Catalyze dephosphorylation
Act as “switches” to turn on or off proteins
![Page 64: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/64.jpg)
![Page 65: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/65.jpg)
Shown to the right are two plots of the energy levels of molecules involved in a reaction such as
A + B > C
over the course of the reaction.
The blue curve depicts the course of the reaction in the absence of an enzyme which facilitates the reaction while the red curve depicts the course of the reaction in the presence of the reaction specific enzyme. The difference in energy level between the beginning state (left side) and the energy necessary to start the reaction (peaks of the curves) is the activation energy of the reaction.
The presence of the enzyme lowers the energy of
![Page 66: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/66.jpg)
Activation Energy and Enzymes II
Shown to the right are three plots of the energy levels of molecules involved in a reaction such as
A + B > C
The first plot depicts the distribution of energy levels of the reactants at body temperature without the presence of an enzyme. The vertical blue line indicates the activation energy level which must be attained for the reaction to occur. The shaded portion of the distribution on the left indicates the proportion of A and B molecules having sufficient energy levels to participate in the reaction.
![Page 67: Chapter 8 Metabolism & Enzymes](https://reader035.fdocuments.in/reader035/viewer/2022062217/568134e5550346895d9c1aa0/html5/thumbnails/67.jpg)
The second plot depicts the distribution of energy levels of the reactants at a temperature higher than body temperature but in the absence of an enzyme. The distribution is shifted to a higher average energy level but the activation energy remains the same. Clearly, there is a higher proportion of molecules at an energy level high enough to participate in the reaction than if the molecules were at body temperature.
The third plot is the same as the first one but with the presence of an enzyme the activation energy for the reaction has been lowered significantly. Thus, the proportion of molecules at an energy level above the activation is greatly increased which means the reaction will proceed at a much higher rate.