Biochemistry Question Set 1

An 11-year-old boy was brought to the emergency room with acute abdominal pain and hematuria. On examination, he had jaundice and pallor. He has a recent history of malaria. His hemoglobin was 5 gm/dL and his peripheral blood smear revealed fragmented RBC, microspherocytes and eccentrocytes (bite cells). The enzyme deficiency responsible for these conditions catalyses which of the following reaction?

A 42-year-old chronic alcoholic male was brought to department of psychiatry for inappropriate behaviour and disturbed memory. On examination, severe retrograde memory loss, disturbed recent memory, confusion and confabulation were noted. Neurologic examination showed nystagmus in left and right gaze and physical examination revealed bilateral pretibial edema and perioral erythema. CT and MRI studies of brain were normal. Which of the following reactions does the deficient vitamin responsible for this condition mediate?

A 5-year-old male was brought by her mother with a chief complaint of weakness. On further inquiry, she reveals weakness is accompanied by increased dizziness, sweating and reeling sensation especially early in the morning. Laboratory findings show increased amount of lactate, uric acid and increased triglyceride levels. Examination shows hepatomegaly. The enzyme deficient in this clinical condition is?

After consumption of three glasses of cheap wine at a rural wine shop, a 33-year-old man developed bloody vomiting and severe watery diarrhea. When brought to emergency department, he had severe dehydration with hypotension. He was treated with intravenous fluids and supportive measures. While he was under treatment, three other men were brought to the emergency department with similar complaints; all of them had consumed wine from the same wine shop. Considering possibility of poisoning, blood samples were sent to laboratory for blood arsenic levels. Blood arsenic levels of all the four patients were significantly high. One of the mechanisms how arsenic causes poisoning is inhibition of pyruvate dehydrogenase complex by trivalent form of arsenic. Which of the following cofactors, required by pyruvate dehydrogenase complex, is bound to the trivalent form of arsenic in arsenic poisoning?

You have been asked to deliver a lecture to the medical students about the effects of various body hormones and neurotransmitters on the metabolism of glucose. Which of the following statements best describe the sympathetic actions on glucose metabolism?

A group of scientists is studying the mechanism of action of various pancreatic hormones in rats. They started with Hormone A secreted by Beta-cells and found that it works by binding to a complex dimeric receptor on the cell membrane and exerts its effects via phosphorylation of different intracellular proteins. Now they are studying another hormone secreted by the Alpha-cells which antagonizes the actions of Hormone A. Which second messenger system would Hormone B utilize to exert its cellular effects?

A 25-year-old female presents to you for routine health maintenance examination. Three of her siblings have died from Tay-Sachs disease. She has no any symptoms and is phenotypically normal. Her parents are also phenotypically normal. What are the chances of this person being heterozygous carrier of the mutation causing this disease?

A 24-year-old male is running a marathon. Upon reaching the finish-line, his serum lactate levels were measured that were significantly increased as compared to the baseline. Which of the following pathways convert the lactate produced by the muscles into the glucose and transports it back to the muscles?