Glucogenic and ketogenic amino acids — MCQs

Researchers are experimenting with hormone levels in mice in fasting and fed states. To test hormone levels in the fed state, the mice are given an oral glucose load and various hormones are measured in a blood sample. Researchers are most interested in the hormone whose blood levels track evenly with C-peptide levels. The hormone the researchers are most interested in is responsible for which of the following actions in the body?

A 4-day-old boy is brought to the physician by his mother because of vomiting, irritability, and poor feeding. Pregnancy and delivery were uncomplicated. Physical examination shows increased muscle tone in all extremities. He appears lethargic. His diapers emit a caramel-like odor. Urine studies are positive for ketone bodies. Supplementation of which of the following is most likely to improve this patient's condition?

A 20-year-old male is brought by ambulance to the emergency room in extremis. He is minimally conscious, hypotensive, and tachypneic, and his breath gives off a "fruity" odor. An arterial blood gas and metabolic panel show anion gap metabolic acidosis. This patient is most likely deficient in which of the following metabolic actions?

A 2-month-old boy is brought to his pediatrician’s office to be evaluated for new onset seizures and poor weight gain. The patient’s father says he is unable to track with his eyes and is unresponsive to verbal stimuli. The patient is hypotonic on physical exam. Further studies show elevated serum lactate levels and elevated levels of alanine and pyruvate. Family history reveals that several distant family members suffered from neurological diseases and died of unknown causes at a young age. Which of the following amino acids should be increased in this patient’s diet?

In a patient with maple syrup urine disease, all of the following amino acids should be restricted in diet except?

A codon is an mRNA sequence consisting of 3 nucleotides that codes for an amino acid. Each position can be made up of any 4 nucleotides (A, U, G, C); therefore, there are a total of 64 (4 x 4 x 4) different codons that can be created but they only code for 20 amino acids. This is explained by the wobble phenomenon. One codon for leucine is CUU, which of the following can be another codon coding for leucine?

A 50-year-old man presents to the office with the complaint of pain in his left great toe. The pain started 2 days ago and has been progressively getting worse to the point that it is difficult to walk even a few steps. He adds that his left big toe is swollen and hot to the touch. He has never had similar symptoms in the past. He normally drinks 2–3 cans of beer every night but recently binge drank 3 nights ago. Physical examination is notable for an overweight gentleman (BMI of 35) in moderate pain, with an erythematous, swollen, and exquisitely tender left great toe. Laboratory results reveal a uric acid level of 9 mg/dL. A complete blood count shows: Hemoglobin % 12 gm/dL Hematocrit 45% Mean corpuscular volume (MCV) 90 fL Platelets 160,000/mm3 Leukocytes 8,000/mm3 Segmented neutrophils 65% Lymphocytes 25% Eosinophils 3% Monocytes 7% RBCs 5.6 million/mm3 Synovial fluid analysis shows: Cell count 55,000 cells/mm3 (80% neutrophils) Crystals negatively birefringent crystals present Culture pending Gram stain no organisms seen Which of the following is the mechanism of action of the drug that will most likely be used in the long-term management of this patient?

A group of researchers wish to develop a clinical trial assessing the efficacy of a specific medication on the urinary excretion of amphetamines in intoxicated patients. They recruit 50 patients for the treatment arm and 50 patients for the control arm of the study. Demographics are fairly balanced between the two groups. The primary end points include (1) time to recovery of mental status, (2) baseline heart rate, (3) urinary pH, and (4) specific gravity. Which medication should they use in order to achieve a statistically significant result positively favoring the intervention?

A 35-year-old man comes to the physician because of worsening pain in his lower back, knees, and shoulders over the past few years. He used to be able to touch his fingers to his toes while standing; now he has difficulty touching his shins. He is wearing a shirt with dark brown stains around the armpits. Physical examination shows bluish-brown sclerae and thickening of the external ear. The range of motion of the affected joints is decreased. X-rays of the spine show calcification of multiple lumbar intervertebral discs. The patient's condition is most likely caused by impaired metabolism of which of the following?

An investigator is studying nutritional deficiencies in humans. A group of healthy volunteers are started on a diet deficient in pantothenic acid. After 4 weeks, several of the volunteers develop irritability, abdominal cramps, and burning paresthesias of their feet. These symptoms are fully reversed after reintroduction of pantothenic acid to their diet. The function of which of the following enzymes was most likely impaired in the volunteers during the study?