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: What are the followings in relation to phosphorylation of mannose residues on glycoproteins?
-Extracellular space
-Lysosome
-Mitochondria
-Nucleus
-Plasma membrane
Answer: Extracellular space: doesn't need phosphorylation of mannose residues on proteins. They will just packed in a vesicles which fuse with plasma membrane to release extracellular proteins.
-Lysosome: does require phosphorylation of mannose residues on glycoproteins in order for them to enter the lysosome. Will help with degradation.
-Mitochondria: They don't need protein phosphorylation. Most mitochondrial proteins will synthesize in the cytosol.
-Nucleus: Protein will present with a nuclear signals (nuclear localization signals) to import or enter the nucleus.
-Plasma membrane: Protein will covalently bind to an hydrophobic lipid anchor that will facilitate protein interaction with cell membrane.
Flashcard 822: A 34 y/o man comes with fascial injury.
-He reports getting hit on the face furing a fistfight at a bar.
-Physical exam: Dark blue periorbital ecchymosis on the right side.
-Ophthalmic & neurologic examinations are otherwise normal.
-Patient is discharge home, but several day later the bruise becomes greenish in color.
-This change in color is best explained by the activity of which enzymes?
Answer: Heme oxygenase
Black eye is cause by RBC that escape into the periorbital tissues.
It could lead to a Greenish color due to heme metabolism by Heme oxygenase that turn it into biliverdin (green color).
Biliverdin (green) will convert to bilirubin (yellow) by biliverdin reductase.
Flashcard 823: In what reaction the followings occurs?
-Aconitase
-Enolase
-Glucose-6-phosphate dehydrogenase
-Glutathione reductase
-Transketolase
Answer: Aconitase: Citric acid cycle. catalyzes isomerization of citrate to isocitrate.
-Enolase: Glycolysis.
-G6PD: occurs in pentose phosphate pathway but occurs in the 1st step. it is irriversible. Deficiency causes hemolytic anemia.
-Glutathione reductase: aid RBC in resisting oxidative stress.
-Transketolase: very important step in pentose phosphate pathway. Reversible. can convert Ribose 5 phosphate to fructose 6 phosphate. Deficient in thiamine (B1) deficiency.
Flashcard 824: What are the followings are associated with in relation to hormones in the body?
-Binding of activated receptors to DNA to modify transcription
-Cyclic AMP-Protein kinase A pathway
-Diacylglycerol-Protein kinase C pathway
-Inositol triphosphate-calcium-calmodulin pathway
-Jak-STAT pathway
Answer: Binding of activated receptors to DNA to modify transcription: (Intracellular receptor)Steroids and thyroid hormones (cortisol, T3/t4, estrogen, vitamin D).
-Cyclic AMP-Protein Kinase A pathway: "FLAT ChAMP GCG" FSH, LH, ACTH, TSH, CRH, hCG, ADH, MSH, PTH, Glucagon, Calcitonin, GHRH.
-Diacylglycerol-Protein Kinase C pathway (DAG) & Inositol triphosphate-calcium-calmodulin pathway (IP3) : "GOAT HAG" GnRH, Oxytocin, ADH (V1 receptor), TRH, Histamine (H1), Angiotensin 2, Gastrin.
-Jak-Stat: Receptor associated tyrosine kinase. "PiGGLET" Prolactin, GH, G-CSF, Erythropoietin, Thrombopoietin.
Flashcard 825: 22 y/o man comes with recurrent blistering on the back of his hands and forarms for the past several years.
-He has used overcounter meds, but symptoms didn't improve.
-He has no exposure to chemicals or animals
-Physical exam: vesicles and erosions on the dorsum of both hands.
-Which enzymes is most likely deficient in this patient in relation to heme synthesis pathway?
Answer: Uroporphyrinogen decarboxylase
because patient present with skin blistering (photosensitivity) due to Porphyria cutanea tarda (PCT)
Flashcard 826: A 5 month old boy is brought to the office by his parents concerning that he has development delay.
-Physical exam: unable to roll. Does not seem to recognize his parents.
-Labs: Impaired tetrahydrobiopterin synthesis.
-Which is most likely deficient in this patient?
Answer: Serotonin or Tyrosine
due to BH4 deficiency that lead to lack of serotonin from tryptophan.
Flashcard 827: What are the followings in relation to gluconeogenesis?
-Glycogen phosphorylase
-Hormone sensitive lipase
-Lipoprotein lipase
Answer: Glycogen phosphorylase: involved in the break down of glycogen. It is the rate-limiting enzyme in glycogenolysis.
Occurs during 1st several hours of fasting. 2 days will most likely be gluconeogenesis.
-Hormone sensitive lipase: enzyme found in adipose tissue, will break down tryglycerides into glycerol & free fatty acids--------> leads to glucose & ketone bodies. It depends on stress hormone (catecholamines, glucagon, ACTH)
-Lipoprotein lipase: enyzme found in bloodstream will break down tryglycerides found chylomicrons & VLDL and turn them to free fatty acids acids. very similar to hormone sensitive lipase.
Flashcard 828: In what disease, deficiency of these enzymes would most likely present?
-Acid a-glucosidase
-Aldolase B
-Fructokinase
-Galactose-1-phosphate uridyl transferase
-Lactase
Answer: Acid a-glucosidase: a-1,4-glucosidase (Pompe disease), a-1,6-glucosidase (Cori disease) "glycogen storage disease" "Very Poor Carb Metabolism"
-Aldolase B: Hereditary fructose intolerence
-Fructokinase: Essential fructosuria
-Galactose-1-phosphate uridyl transferase: Galactosemia (most common in babies)
-Lactase: Lactose intolence (adult), will cause diarrhia after ingestion of dairy products.
Flashcard 829: What are the following substances? What happen due to defiency of these substances?
-Folic acid
-Tocopherol
-Riboflavin
-Pyridoxine
Answer: Folic acid: Vit B9, deficiency of folate could lead to megaloblastic anemia.
-Tocopherol: Vit E, fat soluble vitamin (ADEK), an antioxidant vitamin, Deficiency lead to myelopathy & neurological symptoms.
-Riboflavin: Vit B2, it synthesize FAD (Flavin Adenine Dinucleotide) and FMN (Flavin Mononucleotide). Deficiency lead cheilosis, glossitis, keratis, conjunctivitis, photophobia, lacrimation, sebrorrheic dermatitis.
(seborrheic dermatitis: looks like eczema) Cheilosis: dry scaling in side of lip
Conjuctivitis
- Pyridoxine: Vit B 6, deficiency lead to anemia, peripheral neuropathy and dermatitis, homocysteinuria.
Flashcard 830: Erythroblasts from a bone marrow biopsy sample of a patient with Neonatal jaundice.
-Cells are unable to generate NADPH from glucose metabolism.
-But the cells are able to convert fructose-6-phosphate to ribose-5-phosphate, which is required for nucleic acid synthesis.
-Which enzyme is essential for the latter conversion?
Answer: Transketolase or transaldolase
due to fructose-6-phosphate conversion to ribose-5-phosphate, this reaction occurs in pentose phosphate pathway.
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