#separator:Tab
#html:false
#tags column:5
IMF-090-01-0001-en	Why must excess amino nitrogen be transferred and excreted rather than stored?	Unlike carbohydrate and fat, amino acids have no dedicated inert storage depot, so excess amino nitrogen must be safely transferred and excreted while carbon skeletons enter other pathways.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0002-en	How is the pancreatic protease cascade switched on in the small intestine?	The proteases are secreted as inactive zymogens; enteropeptidase initiates trypsin formation, and trypsin then activates the other enzymes.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0003-en	Why can one inherited amino-acid transporter defect affect both intestine and kidney, and how can it produce pellagra-like features?	Similar carriers serve apical epithelia in both organs; losing selected neutral amino acids can reduce tryptophan availability, producing pellagra-like or neurological manifestations.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0004-en	How do the ubiquitin-proteasome system and autophagy-lysosome pathways divide intracellular protein degradation?	The proteasome degrades many short-lived, regulatory and abnormal cytosolic proteins, whereas autophagy-lysosome pathways digest long-lived proteins, aggregates, membrane proteins and organelles.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0005-en	What are the limitations of nitrogen balance as a measure of protein metabolism?	It estimates intake minus losses but misses unmeasured routes and says little about which proteins change; stable muscle mass can also coexist with altered turnover.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0006-en	How does amino-acid catabolism usually begin, and what carries the amino group?	Rather than releasing free ammonia, aminotransferases move the alpha-amino group to alpha-ketoglutarate, forming glutamate and an alpha-ketoacid; pyridoxal phosphate from vitamin B6 carries the group.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0007-en	Why do plasma aminotransferase activities not directly measure liver function?	They indicate enzyme leakage from injured tissue, read in context; alanine aminotransferase is relatively liver enriched, while aspartate aminotransferase is also abundant in muscle, heart and other tissues.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0008-en	What is transdeamination, and what does oxidative deamination of glutamate produce?	It is amino transfer to glutamate followed by its deamination; mitochondrial glutamate dehydrogenase yields alpha-ketoglutarate, free ammonia and NADH or NADPH, and can run in reverse.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0009-en	Why is ammonia carried in glutamine rather than free, and how is it released for disposal?	Free ammonia is toxic, particularly to brain, so glutamine synthetase uses ATP to join it to glutamate; liver and kidney glutaminase later release ammonia for urea synthesis or urinary buffering.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0010-en	What is the benefit and the cost of the glucose-alanine cycle during fasting?	Muscle pyruvate accepts amino nitrogen to form alanine, which liver converts to glucose and urea; this supports glucose in fasting or catabolic illness but costs muscle protein.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0011-en	Where do the two nitrogens and the carbon of urea come from, and why is the cycle energetically expensive?	One nitrogen enters as free ammonia and the other as aspartate, with carbon from bicarbonate; the cycle consumes three ATP but four high-energy phosphate bonds.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0012-en	How does N-acetylglutamate match urea-cycle capacity to the nitrogen load?	It is the obligatory activator of carbamoyl-phosphate synthetase one, and its own synthesis rises with arginine and amino-acid load.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0013-en	How does the urea cycle connect to citric-acid metabolism?	Argininosuccinate lyase releases fumarate, which passes through malate to oxaloacetate; transamination of oxaloacetate regenerates aspartate, forming the aspartate-argininosuccinate shunt.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0014-en	Why may a neonate with a urea-cycle defect appear normal at first?	Before birth the maternal circulation cleared the infant's nitrogen; hyperammonaemia then emerges, often after protein feeding or catabolic stress.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0015-en	Why does ornithine-transcarbamylase deficiency vary so widely in severity between individuals?	It is X-linked: males can have catastrophic neonatal disease, while in females variable X inactivation produces a range down to episodic symptoms.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0016-en	How does orotic acid distinguish ornithine-transcarbamylase deficiency from carbamoyl-phosphate-synthetase-one or N-acetylglutamate defects?	In ornithine-transcarbamylase deficiency, excess mitochondrial carbamoyl phosphate enters the cytosolic pyrimidine pathway and raises orotic acid; in the proximal defects it is not similarly elevated.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0017-en	How does arginase deficiency typically differ in presentation from other urea-cycle defects?	It often presents more chronically with spasticity and growth or neurological problems, and the ammonia elevation may be less dramatic.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0018-en	Why does acute hyperammonaemia management give glucose and lipid while briefly stopping protein?	Stopping protein briefly limits new nitrogen, while glucose and lipid reverse the catabolism that releases nitrogen from body protein.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0019-en	How does ammonia injure the brain at the level of astrocytes?	Astrocytes convert glutamate and ammonia to glutamine, causing osmotic and metabolic stress, while alpha-ketoglutarate and neurotransmitter pools, mitochondrial function and cerebral blood flow are disturbed.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0020-en	Why does a normal ammonia level not exclude hepatic encephalopathy?	Liver disease also alters inflammation, portal shunting, medications, electrolytes, bleeding, renal function and other toxins, and plasma ammonia correlates imperfectly with symptoms.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0021-en	Why is urinary ammonium more than waste nitrogen?	Renal glutamine metabolism yields ammonium, trapped in tubular fluid and excreted, plus new bicarbonate returned to blood; acidosis increases it, making it a major adaptive acid excretion.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0022-en	Why can the glucogenic or ketogenic classification of an amino acid not predict its whole-body fate?	Classification only describes carbon products, such as leucine and lysine yielding acetyl or acetoacetyl units; actual flux is governed by hormones, tissue and substrate demand.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0023-en	Which step fails in maple-syrup-urine disease, and how is the disease managed?	The thiamine-dependent mitochondrial complex that oxidatively decarboxylates branched-chain ketoacids fails; care limits branched substrates while preserving growth and rapidly reverses catabolic crises.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending
IMF-090-01-0024-en	Why can an unexpectedly high ammonia result be artefactual, and when should treatment not wait for a repeat?	Ammonia rises if blood cells keep metabolising or samples stay warm and delayed; repeat promptly with correct handling, but treat first when clinical suspicion and severe elevation make delay unsafe.	Integrated Medical Foundations; chapter 90, TTS module 1; https://theisegoria.github.io/medical-textbook/integrated-medical-foundations-expanded-english.md; module SHA256 at export: 60e6e0d40f37b0431c9abb22ad8e0762c1e36c5006371a6e2ffb2b2a7124a6eb; editorial review pending	imf lang::en chapter::090 module::090-01 review::pending