Session 18 - Lecture 1 - Carbohydrate Metabolism 3 Flashcards
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1 - Metabolism
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Lecture 1 - Carbohydrate metabolism 3
Lecture 2 - Lipid metabolism
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2 - What did I learn last week?
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What did I learn last week?
Fructose Glucose Galactose G-6-P G-1-P ,--> Glycogen F-6-P Pentose phosphate pathway G-3-P Lactate all enzymes in cytosol
{- summarise glycolysis from 6C sugar to 2 3C molecules (G6P –> G3P –> pyruvate
- regulated on irreversible steps: step 3 crucial
- regulation inhibition by high energy compounds e.g. ATP, NADH and activation by low energy compounds AMP & NAD+
- 3 main dietary sugars ultimately converted into intermediates in glycolysis - everything ultimately after 3C step reducing equiv?
- Lactate dehydrogenase converts pyruvate to lactate in anaerobic conditions
- If muscles anaerobic, lactate released into bloodstream: goes to heart or liver predominantly where same enzyme able to reconvert lactate to pyruvate using NAD available bc tissues are highly oxygenated: way of protecting tissues that may go anaerobic
- PPP shunts out G6P produces 2 things: NADPH (remember this is biosynthetic reducing carrier) and 5C sugar molecules, largely necessary for production of NTs
- If 5C sugars not used for NTs then can re enter glycolysis, but some energy has shunted out there to NADPH
- When energy lvls high - glycolysis inhibited at step 3 so glucose-6-phosphate builds up and feeds out into shunt when biosynthesis possible}
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3 - What do I need to know about energy production from a high CHO diet?
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What do I need to know about energy production from a high CHO diet?
- explain the key role of pyruvate dehydrogenase in glucose metabolism.
- describe the roles of the tricarboxylic acid cycle (TCA cycle) in metabolism.
- explain how the TCA cycle is regulated
- describe the key features of oxidative phosphorylation.
- explain the processes of electron transport and ATP synthesis and how they are coupled.
- describe how, when and why uncoupling of these processes occurs in some tissues.
- compare the processes of oxidative phosphorylation and substrate level phosphorylation.
{1. converts pyruvate into ACoA and that goes into TCA 2. TCA to release predominant amount of energy in sugars
- response to high and low energy molecules
- oxphos - stage 4 metabolism.
- electrons carried on NADH and FADH will be passed onto O2 to make H2O. Energy released will be converted to drive ATP synthesis. Complicated process, will learn simplified form.
- Uncoupled = blocked - passage of electrons can be uncoupled from ATP synthesis (clinically important).
- SLP - production of ATP within metabolic pathways.
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4 - End of stage 2
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End of stage 2
Pyruvate does not enter directly into Stage 3
(Tricarboxylic acid cycle)
Pyruvate dehydrogenase
Stage 1 Diet Protein Carbohydrates Lipids (Triacylglycerols) Alcohol Amino acids Monosaccharides Glycerol Fatty acids Alcohol Stage 2 NH4+ a-keto acids Pyruvate (lactate) Urea Stage 3 CO2 Acetyl CoA 2CO2 NADH NAD+ FAD2H FAD Stage 4 H+ + e- ADP + Pi ATP O2 H2O
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