Cell Biology & Signaling Practice Questions

A 68-year-old man with a history of multiple myeloma is being treated with a novel chemotherapy agent. He reports significant improvement in his symptoms and a reduction in serum M-protein levels. The drug's mechanism of action involves inhibiting a multi-catalytic protease complex responsible for degrading ubiquitinated proteins, thereby leading to the accumulation of misfolded proteins and induction of apoptosis in malignant cells. Which of the following cellular components is the most likely target of this drug?

A 6-month-old male infant presents with recurrent bacterial infections, particularly of the skin and respiratory tract, and delayed umbilical cord separation. Physical examination reveals poor wound healing, gingivitis, and absent pus formation at infection sites. Laboratory studies show persistent leukocytosis with neutrophilia, even between acute infections. A genetic defect leading to impaired neutrophil adhesion to endothelial cells is suspected. Which of the following cell adhesion molecules is most likely deficient in this patient?

A 22-year-old man presents with blurred vision, sudden onset of dyspnea, and chest pain. He has a history of tall stature, long limbs, and scoliosis. Physical examination reveals an arm span significantly greater than his height, arachnodactyly, and a high-arched palate. Cardiac auscultation reveals a diastolic murmur at the left sternal border. An ophthalmological examination shows bilateral lens dislocation. This patient's condition is most likely caused by a genetic defect affecting which of the following extracellular matrix components?