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Lecture 2

BIOLOGY 2A03 Lecture Notes - Lecture 2: V12 Engine, Activation Energy, Chemical Equilibrium


Department
Biology
Course Code
BIOLOGY 2A03
Professor
Graham R.Scott
Lecture
2

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Biological systems, energy can be placed into several categories
Energy exists as kinetic, potential, or both.
Aid in transfer of energy between forms in biological processes
Metabolism = sum of all chemical reactions In cell
Chemical Reactions
Hydrolysis (A-B + H2O A-OH + H-B) - opp. = condensation
Phosphorylation/dephosphorylation (ADP + Pi ATP + H2O)
Types of Reactions
Principles of chemical equilibrium dictate directions of reversible reactions and final conc. Of
reactants and products
Rates of chemical reactions are dependent on activation energy (and temp. /=
reactant/product conc.)
Activation energy, EA= energy needed to pass through transition state
Most biochemical reactions catalyzed
Enzymes = catalysts that Inc. rate of reactions by reducing EA
Not altered by the reaction they catalyze
Reactant bound by enzyme = substrate
Specific to substrate - often catalyze forward and reverse reactions
Enzymes
Enzyme Kinetics
Conc. of substrates [S] and products [P]
1.
Enzyme activity
2.
Max rates = Vmax = [E]*kcat
Enzyme conc. [E]
3.
Michaelis-Menten Equation:
Km+ [S]
Reaction Rate (V) = [S]*Vmax
Kmis [S] at which V = 1/2 Vmax
Affinity of enzyme for its substrate
4.
Rates of Enzyme-Catalyzed Reactions (V) depend on:
Competitive Inhibition - modulator molecule competes with substrate for binding at the active
site
1.
For Some Enzymes, Rates of Reactions can also be regulated by:
Lecture 2: Cell Part 1
Tuesday, January 9, 2018
3:24 PM
BIO 2A03 Page 1
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