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MC
AT
Prep
. Exam
PowerPoint® Lecture Slides are prepared by Dr. Isaac Barjis, Biology Instructor
F binds to allosteric site and the active site of E1 changes shape.
A cannot bind to E1; the enzyme has been inhibited by F.
B C D E
E1
E1
E1
E1
F
3
1
F(end
product)
(endproduct)
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Irreversible Inhibition
Materials that irreversibly inhibit an enzyme are known as poisons The active site of enzyme becomes permanently
unavailable
Aspirin (Acetylsalicylic acid) inhibits cyclooxygenase, thus this enzyme can no longer make prostaglandin, and no more prostaglandin means no more pain
Penicillin inhibits an enzyme unique to certain bacteria
Nerve gas irreversibly inhibits enzymes required by nervous system
Enzyme Kinetics
The Michaelis-Menten model is the one of the simplest and best-known approaches to enzyme kinetics.
The Michaelis-Menten equation for this system is:
Vmax represents the maximum velocity achieved by the system, at maximum (saturating) substrate concentrations. KM (the Michaelis constant; sometimes represented as KS instead) is the substrate concentration at which the reaction velocity is 50% of the Vmax. [S] is the concentration of the substrate S.
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Oxidation-Reduction
Oxidation-reduction (redox) reactions:
Electrons pass from one molecule to another
The molecule that loses an electron is oxidized
The molecule that gains an electron is reduced
Both take place at same time
One molecule accepts the electron given up by the other
Oxidation-Reduction
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Electron Transport Chain
Membrane-bound carrier proteins found in mitochondria and chloroplasts
Physically arranged in an ordered series Starts with high-energy electrons and low-energy ADP
Pass electrons from one carrier to another Electron energy used to pump hydrogen ions (H+) to one side
of membrane
Establishes electrical gradient across membrane
Electrical gradient used to make ATP from ADP – Chemiosmosis
Ends with low-energy electrons and high-energy ATP
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MC
AT
Prep
. Exam
PowerPoint® Lecture Slides are prepared by Dr. Isaac Barjis, Biology Instructor