A 33-year-old woman is brought to the emergency department 30 minutes after being rescued from a fire in her apartment. She reports nausea, headache, and dizziness. Physical examination shows black discoloration of her oral mucosa. Pulse oximetry shows an oxygen saturation of 99% on room air. The substance most likely causing symptoms in this patient primarily produces toxicity by which of the following mechanisms?
AInhibition of mitochondrial complex V
BDegradation of 2,3-bisphosphoglycerate
COxidation of Fe2+
DRise in serum pH
ECompetitive binding to heme
A 2-day-old boy is examined on day of discharge from the newborn nursery. He was born at 39 weeks by vaginal delivery to a primigravid mother. The pregnancy and delivery were uncomplicated, and the baby has been stooling, urinating, and feeding normally. Both the patient’s mother and father have no known past medical history and are found to have normal hemoglobin electrophoresis results. Compared to adult hemoglobin, the infant’s predominant hemoglobin is most likely to exhibit which of the following properties?
ADecreased affinity for 2,3-bisphosphoglycerate
BMore likely to form hexagonal crystals
CMore likely to cause red blood cell sickling
DLower affinity for binding oxygen
EIncreased affinity for 2,3-bisphosphoglycerate
An investigator is conducting a study on hematological factors that affect the affinity of hemoglobin for oxygen. An illustration of two graphs (A and B) that represent the affinity of hemoglobin for oxygen is shown. Which of the following best explains a shift from A to B?
ADecreased serum pCO2
BIncreased serum pH
CDecreased serum 2,3-bisphosphoglycerate concentration
DIncreased body temperature
EIncreased hemoglobin γ-chain synthesis
+ 7 more in the PDF
Browse all chapters