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 841: In what disease the followings are associate with:
-Blood protoporphyrin level
-Erythocyte glucose-6-phosphate dehydrogenase activity
-Erythrocyte glutathione reductase activity
-Erythrocyte transketolase activity
-Serum methylmalonic acid level
-Serum NADPH
Answer: Blood protoporphyrin level: is the second to last enzyme in heme synthesis. It will be high in iron deficiency anemia and lead poisoning.
-G6PD activity: it could lead to hemolytic anemia, when level decreases.
-Erythrocyte gluthathione reductase activity: helps metabolize harmful oxygen species.
-Erythrocyte transketolase activity: will be decrease in thiamine deficiency (wernicke K. syndrome)
-Serum methylmalonic acid level: product of fatty acid oxydation. Converted to succinyl COA by methylmalonyl COA mutase. it will be increase in B12 deficiency.
-Serum NADPH: derived from Vit B3 (niacin)
Flashcard 842: A deficiency of the following enzymes will lead to what disease?
-Delta- aminolevulinate dehydratase
-Delta-aminolevulinate synthase
-Cystathionine synthase
-Glucose-6-phosphate dehydrogenase
-Pyruvate kinase
Answer: D ALA dehydratase: Lead poisoning
-D ALA synthase: Sideroblastic anemia
-Cystathione synthase: usually convert homocystine to cystathionine (with help of B6), thus lead to homocystinuria.
-G6PD: hemolytic anemia
-Pyruvate kinase: (autosomal recessive disease) Hemolytic anemia.
Flashcard 843: In what disease should the followings be restricted?
-Galactose
-Leucine
-Methionine
-Phenylalanine
-Tyrosine
Answer: Galactose: galactosemia (due to deficiency of Galactose-1-phosphate uridyl transferase) (GALT def.)
-Leucine: Maple syrup disease, due to deficiency of branched chain a-ketacid dehydrogenase.
-Methionine: should be restricted in homocysteinuria,because methionine converts to homocystein. Instead you will want to give B12 (cobalamine) to convert to methionine & B6 (pyridoxine) to convert to cysteine to relieve the high level of homocysteine.
-Phenylalanine: Phenylketonuria (def. of phenyl hydroxylase), musty odor, neurological symptoms.
-Tyrosine: restricted in hypertyrosinemia (progressive liver & renal disease) or in alkaptonuria (homogentisate oxidase def.) (black urine on air, black cartillage).
Flashcard 844: A researcher are investigating the relationship between glucose transporters and insulin concentration in various cells & tissues.
-Data are collected in the graph below.
-The graph shows number of glucose transporters found on the surface of 2 types of cells (circles versus triangles) compared to serum insuli concentration.
Which cells types are most likely represented by the circles and triangles?
Answer: Skeletal muscle and renal cells (any other cells as long as it's not adipocytes or skeletal muscle cells)
Circle: Skeletal muscle or adipocytes (insulin dependent). (GLUT 4 receptor)
Triangles: Any other cells (insulin independent).
Flashcard 845: A 2 y/o boy is being evaluated for failure to thirve and developmental delay.
-Past Medical history: recurrent ear infection since age 6 months.
-Physical Exam: coarse facial features, corneal clouding, hepatosplenomegaly and restricted joint mobility.
-Mass spectrometry analysis: Deficient phosphorylation of mannose residues on certain glycoproteins in the golgi apparatus.
-Normally, these proteins are most likely to be transported to which cellular locations?
Answer: Lysosome
due to Inclusion cell (I Cell) disease
which is a defect in protein targetting due to lack of phosphorylation of mannose residues in proteins, which causes lack of protein in lysosome, lead to accumulation of cells debris without degradation in lysosome.
Symptoms: Coarse facial features, corneal clouding, failure to thrive, & cognitive deficits in 1st year of life.
Flashcard 846: What are the followings substances are associated with in relation to cofactors or chemical reaction?
-Biotin
-Folic acid
-Niacin
-Pyridoxine
-Riboflavin
-Thiamine
Answer: Biotin: Vit B7, cofactor for carboxylases enzymes. Ex: Pyruvate carboxylase.
-Folic Acid: Vit B9, cofactor for Nucleic acid synthesis. Deficiency lead to megaloblastic anemia, due to lack of division of cells to turn to normal size RBC but instead their radius becomes bigger.
-Niacin: Vit B3, cofactor for dehydrogenase enzymes (NAD+ & NADP+). Deficiency leads to DDD (pellegra): Diarrhea, Dementia, Dermatitis.
-Pyridoxine: Vit B6, cofactor for transaminase, which means conversion of: amino acids ---> a-keto acid ---> amino acid. Ex: Glutamate to oxaloacetate then to aspartate. Deficiency could lead to homocystinuria.
-Riboflavin: Vit B2, are use in dehydrogenase reaction involving FMN and FAD (Flavin MN or Flavin AD).
-Thiamine: Vit B1, cofactor for dehydrogenase enzymes in Transketolase dehydrogenase. Ex: .....Keto..... Dehydrogenase.
Flashcard 847: A newborn comes with lethargy, vomiting, and hypotonia during fist few days of life.
-Lab: metabolic acidosis with large anion gap, ketosis, & hypoglycemia.
-Concentration of propionic acid is increase in the plasma and urine.
-Metabolism of which amino acids contributes to this patient's condition?
Answer: Valine
Others: "Met Threonine ValLe" (Methionine, Threonine, Valine, Isoleucine), odd chain fatty acids, cholesterol.
due to deficiency of propionyl-CoA carboxylase, which usually convert propionyl CoA to methylmalonyl CoA which will be converted to succinyl CoA (TCA cycle), by methylmalonyl CoA mutase with the help of vit. B12 as a cofactor.
Flashcard 848: A 5 month old boy comes with poor feeding.
-Physical exam: hepatomegaly and hypotonia in all 4 limbs.
-Cardiac auscultation: gallop rhythm
-Chest Xray: Severe cardiomegaly
-Muscle biopsy: Enlarged lysosomes containing periodic acid-schiff (PAS)-positive material.
-Which enzymes is most likely deficient in this patient?
Answer: Acid alpha-glucosidase (alpha 1,4 glucosidase deficiency) or Acid maltase deficiency
due to Pompe disease (Very Poor Carbs Metabolism)
Accumulation of glycogen in lysosomal vesicles.
Present with: Normal glucose levels, severe cardiomegaly.
Flashcard 849: What are the followings in relation to neutralizing toic molecules?
-Cytochrome oxidase
-Cytochrome p450
-Myeloperoxidase
-NADPH
-Superoxide dismutase
Answer: Cytochrome oxidase: final component in electron transport chain, convert molecular oxygen to water. Help synthesizing ATP.
-Cytochrome p450: metabolize endogenous toxins as well as drugs. can lead hepatotoxicity in certain drugs.
-Myeloperoxidase: found in neutrophils, could cause oxidative damage to host cells.
-NADPH: help phagocytic cells destroy bacteria. Deficiency could lead to chronic granulomatous disease, where catalase positive organisms can't get destroy even after being phagocyte by WBC.
-Superoxide dismutase: neutrilizes reactive oxygen species, preventing cell injury and prevent acute compartment syndrome secondary to reperfusion injury.
Flashcard 850: True or False
Some patients with porphobilinogen deaminase deficiency could be asymptomatic for Acute intermittent porphyria
Answer: True
because porphobilinogen deaminase deficiency is not sufficient enough to cause symptoms.
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