280-289 Flashcards
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Glucose metab.
Determines the fate of glucose.
■ —- production per molecule of glucose. The table below assumes that
the — produced in glycolysis is carried into mitochondria via the
—–shuttle. If the glycerol-3-phosphate (G3P) shuttle is used,
the net ATP production would be 36.
Determines the fate of glucose.
■ ATP production per molecule of glucose. The table below assumes that
the NADH produced in glycolysis is carried into mitochondria via the
malate–aspartate shuttle. If the glycerol-3-phosphate (G3P) shuttle is used,
the net ATP production would be 36.
https://drive.google.com/open?id=0B8uJUY-tie8GMmNfTVJqZlZBVWM
https://drive.google.com/open?id=0B8uJUY-tie8GbUNUWGh4bnJMY2s
glycolysis
Also called the Embden–Meyerhof Pathway. (See Figures 7–3.)
■ Occurs in the cytosol, in the absence of O2.
glycolysis
Converts glucose (as glucose-6-phosphate) → two molecules of pyruvate.
■
RLS of glycolysis
Conversion of fructose-6-phosphate → fructose-1, 6-biphosphate via phosphofructokinase
(PFK) is the rate-limiting step.
https://drive.google.com/open?id=0B8uJUY-tie8GRnBNRG5VN3d3ZjQ
https://drive.google.com/open?id=0B8uJUY-tie8GOWNtOUdrMS1CR28
Glucose +x Pi + y ADP + z NAD+ → 2 Pyruvate +x ATP + y NADH + z H+ + 2 H2O
Glucose + 2 Pi + 2 ADP + 2 NAD+ → 2 Pyruvate + 2 ATP + 2 NADH + 2 H+ + 2 H2O
https://drive.google.com/open?id=0B8uJUY-tie8GbC1Fdy1sNVo3MG8
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■ ATP-requiring reactions:■
Hexokinase/Glucokinase: glucose → glucose-6-phosphate
■ PFK: fructose-6-phosphate → fructose-1,6-bisphosphate
ATP-producing reactions:■
Phosphoglycerate kinase: 1,3-bisphosphoglycerate → 3-phosphoglycerate
Pyruvate kinase: phosphoenolpyruvate → pyruvate
PYRUVATE DEHYDROGENASE
■ Pyruvate + NAD+ →
Acetyl-CoA + CO2 + NADH
5 cofactors
Pyrophosphate (B1, thiamine)
■ FAD (B2, riboflavin)
■ NAD (B3, niacin)
■ CoA (B5, pantothenate)
■ Lipoic acid
Also called the Cori cycle (See Figure 7–4.)
■ Occurs in the liver
lactic acid cycle
LA cycle
Prevents lactic acidosis
■ Converts lactate → glucose, which is then reoxidized via glycolysis
LA cycle
Provides quick ATP production during anaerobic glycolysis in muscle and
erythrocytes
■ Results in net loss of 4 ATP per cycle
Citric Acid cycle
- Krebs cycle and the tricarboxylic acid cycle.
Citric acid cycle
Occurs in the mitochondrial matrix.
■ Completes the metabolism of glucose.
Citric acid cycle
Oxidizes acetyl-CoA.
Reduces NAD+ and FAD → NADH and FADH2, which are reoxidized in
the ETC to produce ATP.
citric acid cycle
Tightly regulated by both ATP and NAD+.
■ Stoichiometry of TCA cycle:
Acetyl-CoA + 3 NAD+ + FAD + Pi + GDP + 2 H2O →
2 CO2 + 3 NADH + FADH2 + GTP + 2 H+ + CoA
https://drive.google.com/open?id=0B8uJUY-tie8GU1BjREx1R0tDc1k
https://drive.google.com/open?id=0B8uJUY-tie8GUHVxSVNzczBVU0E
ETC
Also called the respiratory chain (See Figure 7–5.)
■ Occurs in the inner mitochondrial membrane.
ETC
Produces ATP via oxidative phosphorylation of ADP.
ETC
Reoxidizes NADH and FADH2 back → NAD+ and FAD as electrons flow
through a series of —– cytochrome complexes of increasing —- potential
(along a —– gradient).
Cytochromes contain a
Cytochromes contain a central iron atom (similar to hemoglobin), which
can exist in an oxidized ferric (Fe3+) state or a reduced ferrous (Fe2+) state.
Cytochromes receive electrons from
the reduced form of coenzyme Q
(ubiquinone).■
Cytochromes carry electrons as?
Cytochromes carry electrons as flavins, iron-sulfur groups, hemes, and
copper ions
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https://drive.google.com/open?id=0B8uJUY-tie8GNWdVZjBKTlRGNTQ
THE PENTOSE PHOSPHATE PATHWAY
Also called the hexose monophosphate shunt.
Glucose-6-phosphate + 2 NADP+ + H2O →
Glucose-6-phosphate + 2 NADP+ + H2O → Ribose-5-phosphate + 2 NADPH + 2 H+ + CO2
THE PENTOSE PHOSPHATE PATHWAY
THE PENTOSE PHOSPHATE PATHWAY
Occurs in the cytosol.
■ An alternative to glycolysis in the metabolism of glucose.
THE PENTOSE PHOSPHATE PATHWAY
Coverts glucose-6-phosphate → ribose-5-phosphate