Metabolism US Medical PG Flashcards - Medical Study Cards
Master Metabolism with OnCourse flashcards. These spaced repetition flashcards are designed for medical students preparing for NEET PG, USMLE Step 1, USMLE Step 2, MBBS exams, and other medical licensing examinations.
Metabolism Flashcard Deck - 10 Cards
Flashcard 791: What are the following substances?
-Bisphosphoglycerate mutase
-Hexokinase
-Pyruvate kinase
-Transketolase
Answer: Bisphosphoglycerate mutase: involve in the reaction that synthesize 2,3-bisphosphoglycerate, to allow RBC to transport oxygen.
-Hexokinase & Pyruvate kinase: enzymes that are involved in glycolysis. Their deficiency could lead to hemolytic anemia.
-Transketolase: involve in the pentose phosphate pathway reaction. They are in a small amount in Thiamine deficiency. They could also convert ribose-5-phosphate to fructose-6-phosphate.
Flashcard 792: What are the following amino acids?
-Alanine
-Aspartate
-Histidine
-Arginine
-Glutamine
Answer: Alanine & aspartate: glucogenic amino acid, they create products of glycolysis. Alanine metobolize in liver to create pyruvate. Asparate could convert to oxaloacetate.
-Histidine: could convert to histamine to create acids in the stomach.
-Arginine: an intermediate in urea cycle, help remove ammonium from blood.
-Glutamine: could convert to glutamate to create NH4 & HCO3 to cope with high acid in the body.
Flashcard 793: In what reaction Xylulose will be found?
Answer: In the pentose phosphate pathway.
Flashcard 794: 11 y/o girl is evaluated for blurry vision.
- Physical Exam: bilateral lens opacities
-Urine is positive for reducing substances.
-Deficient activity of which enzyme is the most likely cause of this patient's eye condition?
Answer: Galactokinase or Aldose reductase.
They both could cause cataracts.
Flashcard 795: In what disease the followings are associated with?
-Delta-Aminolevulinate dehydratase
-Delta- Aminolevulinate synthase
-Bilirubin glucuronyl transferase
-Porphobilinogen deaminase
-Uroporphyrinogen decarboxylase
Answer: Delta-Aminolevulinate dehydratase: Lead poisoning
-Delta-aminolevulinate synthase: sideroblastic anemia, also requires vit. B6 as cofactor (microcytic anemia)
-Bilirubin glucuronyl transferase: hepatic enzymes responsible for conjugation of bilirubin.
-Porphobilinogen deaminase: Acute intermittent porphyria (present with abdominal pain, portwine color urine and neuropsychiatric problems)
-Uroporphyrinogen decarboxylase: Porphyria cutanea tarda (present with photosensitivity on sun exposed areas)
Flashcard 796: what are the followings in relation to Phenylalanine metabolism?
-Dihydrobiopterin reductase
-Dopamine B-hydroxylase
-Dopamine decarboxylase
-Phenylalanine hydroxylase
-Phenylethanolamine N-methyltransferase
-Tyrosinase
Answer: Dihydrobiopterin reductase: convert BH2 to BH4 in order to use BH4 as a cofactor to convert phenylalanine to tyrosine.
-Dopamine B-hydroxylase: convert dopamine to norepinephrine. Requires Vit. C as cofactor.
-Dopamine Decarboxylase: convert DOPA to dopamine. Requires Vit. B6 as cofactor.
-Phenylalanine hydroxylase: convert phenylalanine to tyrosine. Requires BH4 as cofactor.
-Phenylethanolamine N-methyltransferase: convert norepinephrine to epinephrine. Requires SAM as cofactor.
-Tyrosinase: convert tyrosine (DOPA to melanin). Tyrosinase deficiency will cause albinism.
Flashcard 797: 12 y/o patient present with severe chest pain.
-He has had intermittent substernal chest pain for past few months, occurs after heavy activity.
-BP: 130/80 Pulse: 132/min RR: 24/min
-Physical exam: Anxious appearing boy with rapid but regular pulse.
-Troponin is elevated. ECG reveals ST segment elevations in leads II, III, & aVF.
-Further lab results: Increase serum methionine level.
-Which amino acids is most likely essential in this patient?
Answer: Cysteine
due to homocysteinuria that lead premature thromboembolic event like atherosclerosis and acute coronary syndrome.
Flashcard 798: 6 month old full term boy comes with lethargy and vomiting.
-Patient was breastfed exclusively until 2 days ago when homemade purred food was added to his diet.
-Serum glucose: 30 mg/dL.
-Dx: confirms aldolase B deficiency.
What should be removed from this patient's diet?
Answer: Sucrose or fructose
due to aldolase B deficiency
(sucrose: glucose+fructose) fructose --> fructose 1 phosphate by fructokinase. Fructose 1-phosphate ---> glyceraldehyde by aldolase B.
Aldolase B deficiency: Fructose intolerence
Fructokinase defect or deficiency: Essential fructosuria
Flashcard 799: In between those 2 enzymes, which one of them is most likely will be inhibited in order to treat Acute intermittent porphyria?
a.) ALA synthase
b.) ALA deaminase
Answer: ALA synthase because it's the rate limiting step in heme synthesis, which lead to accumulation of ALA & PBG (porphobilinogen)
ALA deaminase deficiency alone is not sufficient enough to cause Acute intermittent porphyria.
Flashcard 800: 12 y/o male is evaluated for ataxia accompanied by episodic erythematous and pruritic skin lesions and loose stools.
-Labs: Loss of neural aromatic amino acids in the urine.
-This patient's symptoms would most likely respond to what supplements?
Answer: Niacin (vit B3)
(DDD: diarrhea, dementia, dermatitis)
Pellegra symptoms
due to Harnup disease: deficiency of neutral amino acid.
Most common: Tryptophan, because tryptophan is a precursor to make Niacin
others: Alanine, valine, leucine, Isoleucine, serine, threonine, Tyrosine, phenylalanine, tryptophan, histidine.
GAPVLIM
STCAG
TPT
LAH
GA
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