Introducción al metabolismo - biologia.ucr.ac.crbiologia.ucr.ac.cr/profesores/Garro Bernal/Biologia...
Transcript of Introducción al metabolismo - biologia.ucr.ac.crbiologia.ucr.ac.cr/profesores/Garro Bernal/Biologia...
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Metabolismo, anabolismo, catabolismo, anfibolismo, metabolitos primarios,
secundarios e intermedios
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Energía, trabajo, energía potencial y cinética
Fig. 6-1
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La mayor parte de la energíaen las transformaciones se pierdecomo calor
Fig. 6-2
100 units chemical energy
(concentrated)
25 units kinetic energy
(motion)
75 units heat
energy
+
Combustion
by engine
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Reacciones exergónicas
Fig. 6-3
energy
reactants
products
+
+
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Reacciones endergónicas
Fig. 6-4
reactants
products
+
+
energy
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Reactivos y productos del uso de la glucosa
Fig. 6-5
energy
C6H12O6
(glucose)
6 O2
(oxygen)
+
6 CO2
(carbon
dioxide)
6 H2O
(water)
+
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Energía de activación en las reacciones exergónicas
Fig. 6-6
high
low
progress of reaction
energy
content
of
molecules
Activation energy needed
to ignite glucose
energy level of reactants
glucose + O2
CO2 + H2O
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Fotosíntesis como reacción endergónica
Fig. 6-7
C6H12O6
(glucose)
6 O2
(oxygen)
+
6 CO2
(carbon
dioxide)
6 H2O
(water)
+
energy
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Interconversión ADP-ATP
Fig. 6-8
ADP
energy
(a) ATP synthesis: Energy is stored in ATP
(b) ATP breakdown: Energy is released
ATP
ATP
ADP phosphate
phosphate
energy
P P P
P P P
+P P P
P P P+
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Acoplamiento de reacciones bioquímicas
celulares
Fig. 6-9
high-energy
reactants
(glucose)
high-energy
products
(protein)
low-energy
products
(CO2, H2O)
low-energy
reactants
(amino acids)
ATP
exergonic
(glucose breakdown)
endergonic
(protein synthesis)
ADP P+
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Los biocatalizadores (enzimas) reducen la
energía de activación
Fig. 6-10
low
high
energy
content
of
molecules
Activation energy
with catalyst
Activation energy
without catalyst
reactants
products
progress of reaction
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Interacción enzima-
substrato: modelo del
ajuste inducido (Koshland)
Fig. 6-11
The substrates, bonded
together, leave the enzyme;
the enzyme is ready for a
new set of substrates
The substrates and
active site change shape,
promoting a reaction
between the substrates
substrates
active site
of enzyme
Substrates enter
the active site in a
specific orientation
enzyme
1
3 2
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Catálisis en el sitio activo: Fischer versus
Koshland
Modelo de la llave y el candado de Fischer
Modelo del ajuste inducido de Koshland
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Vía metabólica simplificada
Fig. 6-12
PATHWAY 1
Initial reactant Intermediates Final products
enzyme 1 enzyme 2 enzyme 3 enzyme 4
PATHWAY 2
enzyme 5 enzyme 6
A B D E
F
C
G
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(a) A substrate binding to an enzyme
active site
substrate
enzyme
noncompetitive
inhibitor site
Inhibición competitiva y no competitiva
Fig. 6-13a
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(b) Competitive inhibition
A competitive inhibitor
molecule occupies the
active site and blocks
entry of the substrate
Inhibición competitiva y no competitiva
Fig. 6-13b
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noncompetitive
inhibitor molecule(c) Noncompetitive inhibition
A noncompetitive
inhibitor molecule
causes the active site
to change shape, so the
substrate no longer fits
Inhibición competitiva y no competitiva
Fig. 6-13c
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Regulación alostérica de las enzimas mediante
inhibición retroalimentativa
Fig. 6-14
enzyme 1 enzyme 2 enzyme 3 enzyme 4 enzyme 5
isoleucine
(end product)
threonine
(initial reactant)
A B C D
As levels of isoleucine rise,
it binds to the regulatory site
on enzyme 1, inhibiting it
isoleucine
enzyme 1
intermediates
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rateof
reaction
fast
slow
(a) Effect of pH on enzyme activity
For most cellular
enzymes, maximum
activity occurs
at about pH 7.4
For trypsin, maximum
activity occurs at about
pH 8
For pepsin, maximum
activity occurs at about
pH 2
Enzimas: pH óptimo y rangos de temperatura
óptima
Fig. 6-15a
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fast
slow
rateof
reaction
(b) Effect of temperature on enzyme activity
For most human enzymes,
maximum activity occurs
at about 98.6°F (37°C)
Enzimas: pH óptimo y rangos de temperatura
óptima
Fig. 6-15b
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