Absorptive State Flashcards
What is the main pathway by which long-chain fatty acids are catabolised?
Beta-oxidation
What is the process by which fatty acids are broken down into acetyl-CoA units that can enter the citric acid cycle for energy production?
Beta-oxidation
Is glucose-6-phosphate an activator or inhibitor of glycogen synthase?
Glucose-6-phosphate is an allosteric activator of glycogen synthase.
How is glycogen synthase regulated?
Glycogen synthase is regulated allosterically and by covalent modifications such as phosphorylation.
What happens to glycogen synthase when it is phosphorylated?
Phosphorylation leads to the inactivation of glycogen synthase.
Pyruvate + CoA + NAD+ ↔ Acetyl CoA + CO2 + NADH
What is the reaction catalysed by?
Pyruvate dehydrogenase complex
What are the products of the reaction catalyzed by the pyruvate dehydrogenase complex?
The products are acetyl-CoA, CO2, and NADH.
What happens to pyruvate in the reaction catalyzed by the pyruvate dehydrogenase complex?
Pyruvate is converted to acetyl-CoA, with the release of CO2 and the reduction of NAD+ to NADH.
What coenzyme is required in the reaction catalyzed by the pyruvate dehydrogenase complex?
Coenzyme A (CoA) and NAD+ are required for the reaction catalyzed by the pyruvate dehydrogenase complex.
Where does fatty acid synthesis take place in the cell?
Cytoplasm
What is the role of acyl carrier protein (ACP) in fatty acid synthesis?
Intermediates in fatty acid synthesis are covalently linked to acyl carrier protein (ACP), which helps shuttle them through the biosynthesis pathway.
What is the final product of fatty acid synthesis?
Fatty acid synthase generates a 16-carbon fatty acid (palmitic acid) as the final product.
What type of reducing power does fatty acid synthesis use?
Fatty acid synthesis uses NADPH for reducing power to convert carbonyl groups to methylene groups in fatty acid elongation.
What is the role of acetyl CoA carboxylase in fatty acid synthesis?
Acetyl CoA carboxylase catalyzes the first committed step in fatty acid synthesis, converting acetyl-CoA to malonyl-CoA.
How is glucogen synthase regulated?
Glycogen synthase is regulated by both covalent modification (phosphorylation/dephosphorylation) and allosteric regulation (by glucose-6-phosphate).
What is the role of glucose-6-phosphate in the regulation of glycogen synthase?
Glucose-6-phosphate acts as an allosteric activator of glycogen synthase, enhancing its activity to promote glycogen synthesis.
What happens to glycogen synthase when it is phosphorylated?
Phosphorylation leads to inactivation of glycogen synthase, decreasing its ability to synthesize glycogen.
Which molecule does glycogen synthase use to add glucose to the growing glycogen chain?
Glycogen synthase uses glucose-1-phosphate, which is activated as UDP-glucose, to add glucose units to the glycogen chain.
Which molecule transports fatty acids from the cytosol to the mitochondria for energy production?
Carnitine transports fatty acids into the mitochondria for energy production.
What is the role of carnitine in fatty acid metabolism?
Carnitine shuttles fatty acids across the mitochondrial membrane by forming a complex with them, enabling their entry into the mitochondria for beta-oxidation.
What is the reaction that metabolises one molecule of glucose to 2 molecules of pyruvates with the net production of 2ATP?
Glycolysis
