blog | Anatomy2Medicine - Part 8
glucogenesis

Glycogen Synthesis

Glycogen consists of chains of alpha-1,4–linked D-glucose residues with branches that are attached by alpha-1,6 linkages Glycogen is synthesized from glucose. Glycogen degradation produces glucose 1-phosphate as the major product, but free glucose is also formed.   Liver glycogen is used to maintain blood glucose during fasting or exercise.   Muscle glycogen is used to […]

Galactosemia

Galactosemia

Metabolism of galactose Conversion of galactose to intermediates of glucose pathways Galactose is phosphorylated by ATP to galactose 1-phosphate Enzyme is galactokinase. Galactose 1-phosphate reacts with uridine diphosphate (UDP)-glucose and forms glucose 1-phosphate and UDP-galactose. Enzyme is galactose 1-phosphate uridylyltransferase. UDP-galactose is epimerized to UDP-glucose Enzyme is UDP-glucose epimerase. Reaction is readily reversible In the […]

Purine metabolism

Purine metabolism

Purine and pyrimidine metabolism Purine synthesis 5’-Phosphoribosyl-1’-pyrophosphate (PRPP) is the activated substrate in the synthesis of purine and pyrimidine synthesis. The purine base is synthesized on the ribose moiety.   PRPP is formed from ATP and ribose.   The enzyme is PRPP synthetase.   PRPP provides the ribose moiety, reacting with glutamine to form phosphoribosylamine […]

Metabolism during the fed or absorptive state The fate of glucose in the liver Excess glucose is stored in the liver as glycogen, which is used during periods of fasting to maintain blood glucose. Excess glucose can be converted to fatty acids and a glycerol moiety, which combine to form triacylglycerols, which are released from […]

Fatty acid oxidation

Fatty acid oxidation

Activation of fatty acids   In the cytosol, long-chain fatty acids are activated by ATP and CoA, forming fatty acyl CoA Short-chain fatty acids are activated in mitochondria. ATP is converted to AMP  and pyrophosphate (PPi) when a fatty acid is activated.   The PPi produced during the reaction is cleaved by pyrophosphatase to two […]

lipoprotein diagram

Cholesterol Metabolism

Cholesterol is synthesized from cytosolic acetyl coenzyme A (CoA) by a sequence of reactions. Glucose is a major source of carbon for acetyl CoA Cytosolic acetyl CoA forms acetoacetyl CoA, which condenses with another acetyl CoA to form hydroxymethylglutaryl CoA (HMG-CoA)   Acetyl CoA undergoes similar reactions in the mitochondrion, where HMG-CoA is used for […]

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Amino Acid Metabolism

Synthesis of amino acids Messenger RNA contains codons for 20 amino acids Eleven of these amino acids can be synthesized in the body. The carbon skeletons of 10 of these amino acids can be derived from glucose. These 10 are serine, glycine, cysteine, alanine, glutamic acid, glutamine, aspartic acid, asparagine, proline, and arginine tyrosine is […]

glycolysis-vs-gluconeogenesis

Gluconeogenesis

Gluconeogenesis   synthesis of glucose from compounds that are not carbohydrates.   occurs mainly in the liver and to a small degree in the kidney The major precursors for gluconeogenesis are   Lactate   amino acids (which form pyruvate or TCA cycle intermediates) glycerol which forms dihydroxyacetone phos- phate [DHAP] Even-chain fatty acids do not […]

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Whipples disease

Whipple disease multivisceral   Tropheryma whippelii is causative organism (MCQ)   Gram-positive actinomycete Why lymphadenopathy occur in Whipple disease organism-laden macrophages accumulate within the small intestinal lamina propria and mesenteric lymph nodes, causing lymphatic obstruction. (MCQ) Why lymphadenopathy occur in Whipple disease malabsorptive diarrhea occur in Whipple disease malabsorptive diarrhea is due to impaired lymphatic […]

Celiac_Disease_Boulder_Medical_Center

Celiac disese

Celiac disease also known as celiac sprue or gluten-sensitive enteropathy (MCQ) It is an immune-mediated enteropathy  (MCQ) triggered by the ingestion of gluten-containing cereals, such as wheat, rye, or barley, in genetically predisposed individuals. (MCQ) alcohol-soluble fraction of gluten, gliadin, contains most of the disease-producing components.   Pathophysiology :   Gluten is digested by luminal […]