Amino acid metabolism and disorders US Medical PG Flashcards - Medical Study Cards
Master Amino acid metabolism and disorders 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.
Amino acid metabolism and disorders Flashcard Deck - 10 Cards
Flashcard 11: Give the essential, ketogenic amino acids.
Answer: Leu, Lys
Flashcard 12: Give the acidic amino acids.
Answer: Asp, Glu
Flashcard 13: Give the basic amino acids.
Answer: Arg, Lys, His (but His uncharged at normal pH)
Flashcard 14: What amino acids are used to transport ammonium around the body?
Answer: Alanine and Glutamine
Extra: Glutamine is the primary transporter of ammonia from most peripheral tissues to the liver and kidneys. Alanine is specifically used to transport ammonia from skeletal muscle to the liver (via the Glucose-Alanine cycle). \n\nGlutamate is not a transport form; rather, it is the intracellular collector of nitrogen which then transfers the amino group to Glutamine or Alanine.
Flashcard 15: Give the sequence of catecholamine synthesis.
Answer: Phenylalanine, tyrosine, dopa, dopamine, NE, Epi
Flashcard 16: What is the basic enzyme defect and inheritance pattern in phenylketonuria (PKU)?
Answer: Autosomal recessive (AR) deficiency of phenylalanine hydroxylase (PAH) or BH4 (tetrahydrobiopterin).
Extra: Clinical features: Intellectual disability, growth retardation, seizures, fair skin, eczema, musty (mousy) body odor. Treatment: ↓ phenylalanine and ↑ tyrosine in diet (tyrosine becomes essential), BH4 supplementation if applicable. Screening: Occurs 2-3 days after birth (must be after feeding).
Flashcard 17: What is the underlying biochemical defect and clinical presentation of Maple Syrup Urine Disease (MSUD)?
Answer: Deficiency of **α-ketoacid dehydrogenase** (BCKDC) leading to blocked degradation of **branched-chain amino acids** (Isoleucine, Leucine, Valine).
Extra: **Presentation:**
- In infants: Severe CNS defects, intellectual disability, seizures.
- Urine smells like maple syrup/burnt sugar.
- Autosomal Recessive (AR).
**Pathophysiology:**
Increased α-ketoacids in the blood (especially leucine).
Treatment: Restrict branched-chain amino acids in diet; Thiamine supplementation (Vitamin B1) may help in some cases.
Flashcard 18: What are the most common enzyme deficiencies in Homocystinuria?
Answer: Cystathionine β-synthase (CBS) deficiency (most common), Methionine synthase deficiency, or MTHFR deficiency.
Extra: Features: Mental retardation, osteoporosis, tall stature (marfanoid habitus), kyphosis, lens subluxation (downward and inward), atherosclerosis (thromboembolism).
Inheritance: Autosomal Recessive (AR).
Treatment: Varies by defect; may include high doses of Vitamin B6 (pyridoxine), or dietary supplementation of cysteine, folate, and B12. Low methionine diet.
Flashcard 19: How many kcal are produced per gram of protein?
Answer: 4 kcal
Flashcard 20: Carnitine deficiency
Answer: Inability to transport long-chain fatty acids into mitochondria, resulting in weakness, hypotonia, and hypoketotic hypoglycemia.
Extra: - Primary carnitine deficiency is caused by a defect in the transporter responsible for carnitine uptake into cells.
- Secondary causes include organic acidemias (excretion of carnitine as acylcarnitine).
- Hallmark finding: Low serum ketones during hypoglycemia (hypoketotic hypoglycemia) because beta-oxidation cannot occur to provide substrates for ketogenesis.
Keywords: Amino acid metabolism and disorders flashcards, medical flashcards, NEET PG preparation, USMLE Step 1 flashcards, Anki alternative, spaced repetition medical, OnCourse flashcards
