Enter your email to get your 85% OFF code and unlock the full USMLE question bank on the app.
Free notes, MCQs, tables & flowcharts for USMLE Step 3 Biochemistry
An 18-month-old girl is brought to the pediatrician’s office for failure to thrive and developmental delay. The patient’s mother says she has not started speaking and is just now starting to pull herself up to standing position. Furthermore, her movement appears to be restricted. Physical examination reveals coarse facial features and restricted joint mobility. Laboratory studies show increased plasma levels of several enzymes. Which of the following is the underlying biochemical defect in this patient?
ACongenital lack of lysosomal formation
BInappropriate protein targeting to endoplasmic reticulum
CFailure of mannose phosphorylation
DInappropriate degradation of lysosomal enzymes
EMisfolding of nuclear proteins
You examine an infant in your office. On exam you observe hypotonia, as well as the findings shown in Figures A and B. You order laboratory testing, which demonstrates the findings shown in Figure C. Which of the following is the most likely pathologic mechanism involved?
AAccumulation of galactocerebroside
BAccumulation of ceramide trihexoside
CAccumulation of GM2 ganglioside
DAccumulation of glucocerebroside
EAccumulation of sphingomyelin
An investigator is studying the function of the endoplasmic reticulum in genetically modified lymphocytes. A gene is removed that facilitates the binding of ribosomes to the endoplasmic reticulum. Which of the following processes is most likely to be impaired as a result of this genetic modification?
AProduction of secretory proteins
BNeutralization of toxins
CUbiquitination of proteins
Dα-Oxidation of fatty acids
ESynthesis of ketone bodies
+ 7 more in the PDF
Browse all chapters