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Metabolismo celular.
Diego Iriarte León.Biología y Ciencias Naturales.
Metabolismo celular.
Definición:son los procesos químicos que ocurren dentro de la célula para mantener la vida.
Acoplamiento Quimiosmótico.
!"
Actividad enzimática.
Vías metabólicas
En presencia de oxígeno.
Catabolismo.
Fermentación.
En ausencia de oxígeno.
Respiración celular.
Glucolisis.
La célula transforma la glucosa en dos moléculas de piruvato o ácido pirúvico.
Se forman 2 NADH.
¿Cómo funciona el NADH?
LE 9-6_3
Mitochondrion
Glycolysis
Pyruvate Glucose
Cytosol
ATP
Substrate-level phosphorylation
ATP
Substrate-level phosphorylation
Citric acid
cycle
ATP
Oxidative phosphorylation
Oxidative phosphorylation: electron transport
and chemiosmosis
Electrons carried
via NADH
Electrons carried via NADH and
FADH2
LE 9-8
Energy investment phase
Glucose
2 ATP used 2 ADP + 2 P
4 ADP + 4 P 4 ATP formed
2 NAD+ + 4 e– + 4 H+
Energy payoff phase
+ 2 H+ 2 NADH
2 Pyruvate + 2 H2O
2 Pyruvate + 2 H2O
2 ATP
2 NADH + 2 H+
Glucose
4 ATP formed – 2 ATP used
2 NAD+ + 4 e– + 4 H+
Net
Glycolysis Citric acid cycle
Oxidative phosphorylation
ATP ATP ATP
LE 9-11 Pyruvate (from glycolysis, 2 molecules per glucose)
ATP ATP ATP
Glycolysis Oxidation phosphorylation
Citric acid cycle NAD+
NADH
+ H+
CO2
CoA
Acetyl CoA
CoA
CoA
Citric acid cycle CO2
2
3 NAD+
+ 3 H+
NADH 3
ATP
ADP + P i
FADH2
FAD
LE 9-12_4
ATP ATP ATP
Glycolysis Oxidation phosphorylation
Citric acid cycle
Citric acid
cycle
Citrate
Isocitrate
Oxaloacetate
Acetyl CoA
H2O
CO2
NAD+
NADH
+ H+
!-Ketoglutarate
CO2
NAD+
NADH
+ H+ Succinyl CoA
Succinate
GTP GDP
ADP
ATP
FAD
FADH2
P i
Fumarate
H2O
Malate
NAD+
NADH
+ H+
LE 9-13
ATP ATP ATP
Glycolysis Oxidative
phosphorylation: electron transport and chemiosmosis
Citric acid
cycle
NADH
50
FADH2
40 FMN
Fe•S
I FAD
Fe•S II
III Q
Fe•S
Cyt b
30
20
Cyt c
Cyt c1
Cyt a
Cyt a3
IV
10
0
Multiprotein complexes
Free
ene
rgy
(G) r
elat
ive
to O
2 (k
cal/m
ol)
H2O
O2 2 H+ + 1/2
LE 9-14
INTERMEMBRANE SPACE
H+ H+
H+ H+
H+
H+
H+
H+
ATP
MITOCHONDRAL MATRIX
ADP
+
P i
A rotor within the membrane spins as shown when H+ flows past it down the H+ gradient.
A stator anchored in the membrane holds the knob stationary.
A rod (or “stalk”) extending into the knob also spins, activating catalytic sites in the knob.
Three catalytic sites in the stationary knob join inorganic phosphate to ADP to make ATP.
LE 9-15
Protein complex of electron carriers
H+
ATP ATP ATP
Glycolysis Oxidative
phosphorylation: electron transport and chemiosmosis
Citric acid
cycle
H+
Q
III I
II
FAD FADH2
+ H+ NADH NAD+
(carrying electrons from food)
Inner mitochondrial membrane
Inner mitochondrial membrane
Mitochondrial matrix
Intermembrane space
H+
H+
Cyt c
IV
2H+ + 1/2 O2 H2O
ADP +
H+
ATP
ATP synthase
Electron transport chain Electron transport and pumping of protons (H+),
Which create an H+ gradient across the membrane
P i
Chemiosmosis ATP synthesis powered by the flow
of H+ back across the membrane
Oxidative phosphorylation
LE 9-16
CYTOSOL Electron shuttles span membrane 2 NADH
or
2 FADH2
MITOCHONDRION
Oxidative phosphorylation: electron transport
and chemiosmosis
2 FADH2 2 NADH 6 NADH
Citric acid cycle
2 Acetyl CoA
2 NADH
Glycolysis
Glucose 2
Pyruvate
+ 2 ATP
by substrate-level phosphorylation
+ 2 ATP
by substrate-level phosphorylation
+ about 32 or 34 ATP
by oxidation phosphorylation, depending on which shuttle transports electrons form NADH in cytosol
About 36 or 38 ATP Maximum per glucose:
LE 9-17a
CO2
+ 2 H+ 2 NADH 2 NAD+
2 Acetaldehyde
2 ATP 2 ADP + 2 P i
2 Pyruvate
2
2 Ethanol
Alcohol fermentation
Glucose Glycolysis
LE 9-17b
CO2
+ 2 H+ 2 NADH 2 NAD+
2 ATP 2 ADP + 2 P i
2 Pyruvate
2
2 Lactate
Lactic acid fermentation
Glucose Glycolysis
LE 9-18
Pyruvate
Glucose
CYTOSOL
No O2 present Fermentation
Ethanol or
lactate
Acetyl CoA
MITOCHONDRION
O2 present Cellular respiration
Citric acid cycle
LE 9-19
Citric acid
cycle
Oxidative phosphorylation
Proteins
NH3
Amino acids
Sugars
Carbohydrates
Glycolysis
Glucose
Glyceraldehyde-3- P
Pyruvate
Acetyl CoA
Fatty acids
Glycerol
Fats
