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10 Cards in this Set
- Front
- Back
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What are micro-domains within a membrane? |
Leaflet specific proteins causing asymmetry within a membrane Extracellular leaflet more glycolipids Certain phospholipids present more on cytosolic side or extracellular side Dead cells present inner leaflet phospholipids on outer for identification |
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What are membranous rafts? |
Specialised micro-domains containing certain lips and proteins Small and transient, functional significance |
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How are fats digested and absorbed in the gastrointestinal tract? |
Large globules emulsified by bile in duodenum Pancreatic lipase produces fatty acids and mono-glycerides by breaking down glycerol and fatty acids to give micelles (O) |
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How are fats mobilised and stored? What are lacteals? |
Micelles break down and enter epithelium Chylomicrons containing fats transported out and into lacteals (Lymphatic fat absorption areas in the villi) LDLs transport through bloodstream Stored in adipose tissue for energy |
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Give a brief overview of the fatty acid pathway |
Lipogenesis Cytosolic mostly Acetyl-CoA source, intermediate between fat and carb metabolism Mitochondrial membrane impermeable to acetyl-coA, so transported via citrate Acetyl CoA -> palmitate |
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What is the reaction sequence of fatty acid synthesis? |
Production of malanoyl CoA catalysed by acetyl CoA carboxylase and BIOTIN cofactor
Activation by acyl carrier Elongation by 2C adhesion: Condensation Reduction Dehydration Reduction |
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How does FA synthase catalyse the fatty acid genesis pathway? |
Phosphopantetheine (ACP) bound to FA synth which acts as a swinging acyl carrying arm, allowing interaction with all active sites |
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What is the overall reaction of palmitate synthesis? |
Acetyl-CoA + 7 malanoyl-CoA + 14 NADPH + 14H+ -> palmitate + 7CO2 + 6H2O + 8CoA-SH + 14NADP+ |
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How is lipogenesis regulated? |
Feedback inhibition of palmitoyl CoA by acetyl CoA carboxylase, fatty acid synthesis, pentose phosphate Hormonal regulation Transcriptional regulation of enzymes |
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Describe the relationship between lipogenesis and beta-oxidation |
Almost a reversal of one another B-oxidation: Oxidation Hydration Oxidation Thiolytic cleavage/hydrolysis to form acetyl CoA and acyl-CoA from palmitate repeated 7 times to produce 8 acetyl CoA |
