250-259 Flashcards
Covalent bonds:
Covalent bonds: Strong molecular interactions mediated by shared electrons.
Noncovalent bonds:
Noncovalent bonds: Weak, reversible molecular interactions
Van der Waals bonds:
Van der Waals bonds: A nonspecific attraction (occurs when any two
atoms are 3–4 Å apart).
water
Polar.
■ Triangular.
■ Highly cohesive.
■ Excellent solvent for polar molecules.
■ Weakens ionic and H-bonds.
Catalyzes the reaction between CO2 and H2O.
■ Extremely fast enzyme.
Carbonic Anhydrase
Located largely in erythrocytes and kidneys.
■ A metalloenzyme: contains zinc.
Carbonic Anhydrase
The total energy of a closed system is conserved.
First law of thermodynamic
The entropy of a closed system always increases.
■ Second law of thermodynamics
Direct calorimetry:
Direct measurement of the amount of heat produced
in a given system.
Indirect calorimetry:
Measurement of the amount of heat produced in
terms of inhaled O2 and exhaled CO2.
Highly specific catalysts for biochemical reactions.
■ Classified according to their mechanism of action.
enzymes
https://drive.google.com/open?id=0B8uJUY-tie8GbzB2bGljMl93NHc
https://drive.google.com/open?id=0B8uJUY-tie8GR1ZtdkU4VU50aVk
Composed of proteins combined with nonprotein structures (either
organic or inorganic) that aid in their function
Metallic Coenzymes
Coenzymes
■ Cofactors
■ Prosthetic groups
metallic coenzymes
Coenzyme:
Nonprotein portion of an enzyme.
Apoenzyme:
Protein portion of an enzyme. Catalytically inactive by itself.
Haloenzyme: ■
Complete, catalytically active enzyme.\
= Apoenzyme + Coenzyme
Isozymes:
Enzymes with subtle molecular differences that catalyze the
same reaction.
Oxidoreductases:
■
Catalyze redox reactions.
Transferases:
Catalyze the transfer of functional groups.
Hydrolases: ■
Catalyze bond cleavage by hydrolysis.
Isomerases:
Catalyze a change in molecular structure.
Lyases:
Catalyze bond cleavage by elimination.
■
Ligases:
Catalyze the union of two molecules.
Substrate-binding induces a conformational change in an enzyme.
■ The energy produced by these changes enables the reactions to progress
induced fit model
Increasing substrate concentration —- reaction rate only until the
—— —— sites are saturated.
Increasing substrate concentration increases reaction rate only until the
enzyme-binding sites are saturated.
Maximum reaction velocity (Vmax) is achieved when any further —-
in substrate concentration —— increase reaction rate.
Maximum reaction velocity (Vmax) is achieved when any further increase
in substrate concentration does not increase reaction rate.
The Michaelis constant (Km) is the substrate concentration when the initial
reaction velocity (vi) is —– of the maximum reaction velocity (Vmax).
The Michaelis constant (Km) is the substrate concentration when the initial
reaction velocity (vi) is half of the maximum reaction velocity (Vmax).
ΔG = ΔGP− ΔGS
Determines reaction direction.
■ If ΔGS > ΔGP, then ΔG will be negative and the reaction will proceed
spontaneously toward equilibrium.
Equilibrium is attained when ΔG = —-
Equilibrium is attained when ΔG = 0.
vi =
Vmax · [S]
Km + [S]
https://drive.google.com/open?id=0B8uJUY-tie8GU3FWZ1l6T3JJa3M
Reactions are based on their ΔG (see Table 5–2).■
Exergonic
■ Endergonic
A: Any reaction with enzyme present.
■ B: Equilibrium —– of the reaction.
■ Enzymes have— —- on reaction equilibrium
A: Any reaction with enzyme present.
■ B: Equilibrium constant of the reaction.
■ Enzymes have no effect on reaction equilibrium
https://drive.google.com/open?id=0B8uJUY-tie8GOUVDUUlxSV9lSjA