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32 Cards in this Set
- Front
- Back
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Which complex's contain cytochromes, and what oxidation/reduction cofactor do these contain...
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...a haeme group
(complex 3 and 4) |
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Adrenaline stimulates Glycogen metabolism...
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...in both muscle and liver
Glucagon just in liver |
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Phosphorylase kinase activated by
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Calcium ions (bind calmodulin)
and... PKA phosphorylates it - via cAMP cascade |
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Glycogen synthase is activated by....
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dephosphorylation (by PP1 liberated from ....)
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Alanine and glutanine major substrates for Gluconeogenesis?
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Yep!
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Fatty acid oxidation reaction steps (draw it out!)
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dehydrogenase (oxidation by FAD)
Hydration Oxidation - NAD this time Thiolysis |
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Patient with liver disease problems?
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Jaundice
problems with blood clotting Severe hypoglycaemia plasma albumin low blood ammonia up |
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Glucogenic and Ketogenic amino acid
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Isoleucine
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product of transamination reactions of many amino acids
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glutamic acid
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Body iron store controlled by?
Transported in plasma bound to? Uptake into cells by? |
Intestinal mucosa
transferrin receptor mediated endocytosis |
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Glucagon's effect on Glycogen metabolism
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Liver affected
Gs (inherant GTPase activity ensures not all glycogen broken down!) to PKA - Phosporylates; Phosphorylase kinase - activates (which then phosphorylates Glycogen phosphorylase - to a form ) Glycogen synthase a to b form - inactive Phosphorylates PP1 - inactivates (also phosphorylates part of Glyc phosphorylase to make susceptible to breakdown by PP1) |
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Glucose's role in causing Glycogen synthesis switch on
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High glucose inhibits Glyc Phosphorylase a, by shifting eqm to T state - has bound PP1, which dephosphorylates to b form, and is thereby released.
PP1 then goes on to dephosphorylate Glycogen synthase - synthesis turned on! |
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Adrenalines action on liver to increase glycogen metabolism
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on alpha receptors - IP3 cascade - increased calcium - activates PK
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Difference between M and L isoform of Glycogen phosphorylase
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M b form can be allosterically activate by AMP, and inhibited by ATP and G6P (reflects intracellular energy charge)
L a form allosterically inactivated by glucose |
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Allosteric activator of b form of Glycogen synthase?
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G 6 P - very high concs
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Glycerol 3 phosphate shuttle?
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Mainly in Skele muscle - to maintain high rate of Ox Phos
DHAP reduced to Glycerol3Phos by cytosolic Glycerol 3 phos dehydrogenase Glycerol3phos oxidised back (giving NADH's electrons to FAD (part of ETC - goes on to release QH2))by inner mito memb bound Glycerol 3 phos dehydrogenase |
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Von gierke disease?
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Swollen abdomen because Liver stuffed with glycogen
Due to G 6 Pase deficiency or lack of transporter into SER Severe Hypoglycaemia between meals. |
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McArdle Disease
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Lack of Muscle Phosphorylase
Cant do strenuous exercise - need use fats for exercise - evidence for isozymes |
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Type VIII glycogen metabolism disease
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Absense of Phosphorylase kinase
Enlarged liver/abdomen Hypoglycaemic between meals |
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Activators + inhibitors of PFK
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+ve;
Fructose 2,6 BP AMP -ve; ATP, H+, citrate Because committed step - controlled by energy charge, acid status and number of fat precursors |
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Why is Gluconeogenesis not exact reverse of glycolysis?
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Irreversible steps of Gluconeogenesis (LARGE free energy change)
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Gluconeogenesis energy cost? Where used
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4 ATP 2 GTP
2 ATP = 2Pyruvate to 2 Oxaloacetate 2 from 3Phosphoglycerate to 1,3Bisphosphoglycerate |
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Pyruvate carboxylase cofactor?
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Biotin with CO2 bound
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Why glucose over other monosaccharides?
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Low tendency to non-enzymatically glycosylate proteins and therefore deactivate them.
Due to high stability in ring structure |
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Galactose metabolism
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Phosphorylated by ATP,
UDP-glucose added - so to UDP galactose and Glucose 1 phosphate (which can go into Glycolysis pathway) UDP galactose to UDP glucose by enyzme, keep cycling! |
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Example of alternative splicing?
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L and M isoform of bifunctional enzyme of Glycolysis - PFK2 and F-2,6-BPase
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Galactosaemia
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Cant catalyse (enzyme lack);
Galactose 1 phos + UDP glucose to UDP Galactose + Glucose 1 phosphate |
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Pyruvate dehydrogenase
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Very important regulatory step of pyruvate metabolism.
Enzyme has 3 activities; Pyruvate dehydrogenase (TPP) Dihydrolipoamide acetyltransferase (Lipoic acid) Dihydrolipoamide Dehydrogenase (FAD - regenerated by NAD) |
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Importance of Pentose Phosphate pathway
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Need to create NADPH for synthesis, and for glutathione reduction - this important to detoxify H2O2 (strong oxidiser) - otherwise in RBCs it oxidises Hb and prevents O2 carrying capacity.
CE G6PD deficiency - haemolytic anaemia following fava beans/ox. drugs - Hb oxidatively damaged and then these cells containing it are destroyed by spleen. |
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MCAD deficiency
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Fasting Hypoglycaemia
No ketosis on fasting Seizure coma death Give alternative energy source |
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LCAD deficiency
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Similar to carnitine deficiency;
skeletal muscle weakness fatty infiltration of organs |
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Insulins effects on fat metabolism
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Insulin (vs glucagon) stimulates AcCoA carboxlase, via enzyme phosphorylation state (?)
-FA synthesis committed step ALSO Insulin increases PP pathway to provide NADPH |
