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 821: 31 y/o patient present with myalgias, anorexia, & skin rash.
-He doesn't do drugs or alcohol.
-He has been consuming large amounts of raw egg whites for the past several months.
-Physical exam: macular dermatitis of the extremities.
-A water-soluble vitamin deficiency is suspected as the cause of his condition.
-Which biochemical conversions most likely uses the deficient vitamin as a cofactor?
Answer: Pyruvate to axaloacetate.
Biotin: cofactor for carboxylase reactions.
because the patient has biotin (Vit. B7) deficiency due to dermatologic changes (macular dermatitis) & large consumption of raw eggs, because raw eggs contain biotin-binding avidin that loves to connect to biotin which will lead to deficiency of biotin.
symptoms: mental status changes, dermatitis, metabolic acidosis due to high conversion of pyruvate to lactic acid due to lack of biotin cofactor to convert to oxaloacetate.
Flashcard 822: What enzymes are found in the following points and what disease/symptoms they will present with?
Answer: A.) Lactase:
Lactose intolerence (very rare in neonates), occurs in adults.
B.) Aldose reductase:
when increases, due to (GALT) Galactose-1-phosphate uridyl transferase or (GALK) Galactokinase deficiency. it could lead to cataracts.
C.) Galactokinase:
Deficiency could lead to high galatose, which would converted to galacticol, to cause cataracts.
D.) Galactose-1-phosphate uridyl transferase:
The most common cause of Galactosemia in neonate. Presents with variety of symptoms: Vomiting, jaundice, hepatomegaly, cataracts, E. coli infections.
E.) Phosphoglucoisomerase, it will not be able to convert to energy.
Flashcard 823: What are the followings in relation to conversion to pyruvate & lactic acid?
-Alanine
-Asparagine
-Galactose
-Glycerol
-Lysine
-Serine
Answer: Alanine: can be converted to pyruvate by removing an NH3 group from alanine.
-Serine: can be converted to pyruvate
-Asparagine: can be converted to asparate ---> glutamate & oxaloacetate.
-Galactose: could convert to lactate, which will increase lactic acid in patients with pyruvate dehydrogenase deficiency.
-Glycerol: can be converted to G3P which can be converted to pyruvate and lactic acid.
-Lysine: Cannot be converted to Pyruvate. (lysine & leucine are the only two AA that can't be converted to pyruvate)
Flashcard 824: A research develops an agent that specifically blocks interaction of inositol triphosphate with its intracellular receptor.
-Compared to the control cells ,decreased activity of which enzyme is most likely to be observed in the experimental cells?
Answer: Protein kinase C
because without IP3 and DAG protein kinase C can't form.
Flashcard 825: What are the followings in relation to biotin deficiency?
-Glucose to ribose-5-phosphate
-Pyruvate to acetyl-CoA
-Pyruvate to alanine
-Pyruvate to oxaloacetate
-Succinate to oxaloacetate
Answer: Glucose to ribose-5-phosphate: Niacin (B3) cofactor. NADPH.
-Pyruvate to acetyl-CoA: Niacin (B3), thiamine (B1), riboflavin (B2), & Pantothenic acid (B5) & lipoic acid. with Pyruvate dehygrogenase enzyme.
-Pyruvate to alanine: (transaminase reaction) uses cofactor B6 (pyridoxine)
-Pyruvate to oxaloacetate: uses cofactor B7 (Biotin)
-succinate to oxaloacetate: requires 2 enzymes: Succinate dehydrogenase, Malate dehydrogenase. Requires Riboflavin (B2) for FAD, Niacin for NAD+.
Flashcard 826: What are the followings in relation to lesch-nyhan syndrome?
-Aspartate carbamoyltransferase
-Dihydroorotase
-Hypoxanthine-guanine phosphoribosyltransferase
-Phosphoribosyl pyrophosphate amidotransferase
-Ribonucleotide reductase
-Thymidylase synthase
Answer: Aspartate carbamoyltransferase, Dihydroorotate, thymidilate synthase: involved in the pyrimidine synthesis, will not be affected.
-HGPRT: will decrease, not increase.
-Phosphoribosyl pyrophosphate amidotransferase: will increase due to high demands of purines synthesis cause by the disease.
-Ribonucleotide reductase: involved in converting ribose sugar into deoxyribose forms. It will not be affected. It involves in pyrimidines synthesis.
Flashcard 827: A 6 month old boy ic brought to the office by his mother concerning he's not developing normally.
-Physical exam: delayed developmental milestone & hypotonia.
-He has tendency to aggressively bite his own lips and fingers.
-Labs: Elevated blood uric acid level.
-Activity of what enzymes is most likely increased as a result of this patient's symptoms?
Answer: Phosphoribosyl pyrophosphate amidotransferase (PRPP)
due to lesch nyhan syndrome (dystonia, choreathetosis, etc...), deficiency of HGPRT
HGPRT: Hyperuricemia, Gout, Piss off (aggression), Retardation, dysTonia.
Will present with increase uric acid which leads to Gout & increased demand for de novo purine synthesis.
Flashcard 828: A study is being performed that includes certain men
-Further analysis shows that these men have an X-linked mutation affecting the phosphoribosyl pyrophosphate (PRPP) synthetase gene.
-This lead to increased substrate conversion.
-What organ is most likely to develop pathology secondary to this mutation?
Answer: Joints
due to Gout, PRPP leads to high purines and uric acid that leads to gout.
Flashcard 829: What are the followings in relation to vitamin deficiency?
-Abnormal oxidative decarboxylation of ketoacids.
-Abnormal proline hydroxylation
-Abnormal transamination
-deficient methionine synthesis
-Diminished synthesis of purines
Answer: Abnormal oxidative decarboxylation: Thiamine (B1) deficiency
-Abnormal proline hydroxylation: vit. C deficiency
-Abnormal transamination: Vit. B6 (pyridoxine) deficiency
-Deficient methionine synthesis: Vit. B12 (cobalamine) deficiency.
-Diminished synthesis of purines: Vit B9 (folate) deficiency
Flashcard 830: The followings compounds will serve as a precursor to what?
-Arginine
-Carotene
-Cholesterol
-Orotic acid
-Phenylalanine
-Tryptophan
Answer: Arginine: precursor to urea, nitric oxide, ornithine, agmatine, creatine.
-Carotene: Precursor to vit. A.
-Cholesterol: precursor to steroid hormones.
-Orotic acid: Precursor to pyrimidine to synthesize DNA.
-Phenylalanine: Precursor to tyrosine to create catecholamines.
-Tryptophan: Precursor to Niacin (B3)
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