Term
| Is the Krebs Cycle an amphibolic pathway? (does it involve both catabolism and anabolism?) |
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Definition
| Yes. Oxidative catabolism of CHO, fats, and proteins. Provides precursors for biosynthetic pathways. |
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Term
| What is the precursor for both the glycerol and fatty acid component of triacylglycerols? |
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Definition
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Term
| What complex links glucose metabolism to FA synthesis? |
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Definition
| pyruvate dehydrogenase complex. This reaction converts pyruvate to acetyl CoA by dehydrogenation and decarboxylation. |
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Term
| Can FAs be converted into Carbs? |
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Definition
| NO. pyruvate dehydrogenase reaction is not reversible. |
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Term
| Are fatty acids with odd numbered carbon atoms glucogenic? |
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Definition
| Yes, partially can be converted to glucose due to propionyl CoA formed by beta oxidation. FAs with odd number of carbon atoms are not common in the diet. |
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Term
| What amino acids are purely ketogenic? |
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Definition
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Term
| Can fatty acids be converted into glucogenic amino acids? |
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Definition
| No. the pyruvate dehydrogenase reaction is not reversible. |
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Term
| What indispensable amino acids produce acetyl CoA directly? |
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Definition
| isoleucine, threonine, phenylanlanine, tyrosine, lysine and leucine. |
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Term
| what organ is the site of synthesis of many different proteins, both structural and plasma borne from amino acids? |
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Definition
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Term
| What happens to the acetyl CoA that cannot be used as energy? |
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Definition
| It can be used for the formation of the ketone bodies. |
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Term
| Role of insulin in a fed state: |
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Definition
| insulin is secreted by beta cells and is responsible for the direction of energy metabolism. |
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Term
| What hormones initiate the action of hepatic glycogenolysis? |
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Definition
| Glucagon secreted by alpha cells of pancreas and epinephrine (adrenaline) and nonepinephrine. |
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Term
| What type of hormones are epinephrine and nonepinephrine? |
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Definition
| Catecholamine hormes because they are the derivatives of the alcohol catechol. |
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Term
| True or False: Does muscle glycogenolysis stimulated by catecholamines provide glucose only for use by the muscle in which the glycogen has been stored? |
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Definition
| True. Phosphorylated glucose cannot cross the cell membrane. Muscle tissue lacks glucose 6-phosphatase and cannot release glucose into circulation. |
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Term
| amino acids needed as substrates to initiate gluconeogenesis are made available through what hormone? |
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Definition
| glucocorticoids secreted by the adrenal cortex. Alanine is the principal gluconeogenic substrate and stimulates glucagon. |
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Term
| During fasting, what does glucagon do to the level of cAMP in adipose cells? |
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Definition
| it raises the level of cAMP which activates a lipase that hydrolyzes stored triacylglycerols. |
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Term
| When muscles are inhibited from taking up glucose by catecholamines during fasting, what is their major source of energy? |
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Definition
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Term
| What amino acids cannot contribute at all to gluconeogenesis? |
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Definition
| leucine and lysine because they are totally ketogenic. |
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Term
| What are the major users of glucose? |
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Definition
| RBCs- convert glucose by way of glycolytic pathway to lactate. Adipose Tissue - uses glucose as a precursor for glycerol and FA components of triacylglycerols. Muscle - uses glucose for synthesis of glycogen by glycolysis and the TCA cycle |
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