Biology, Genetics & Bone Healing MCQs

Denosumab is utilized in the treatment of osteoporosis and giant cell tumor of bone. Its mechanism of action most closely mimics which naturally occurring endogenous molecule?

According to Perren's strain theory, what is the maximum interfragmentary strain that allows for primary bone healing to occur?

Demineralized bone matrix (DBM) is commonly used as a bone graft substitute in spinal fusions. Which of the following best describes its biological properties?

The compressive stiffness of articular cartilage is primarily provided by which of its structural components?

Bone morphogenetic protein-2 (BMP-2) utilizes a specific intracellular signaling pathway to induce osteoblast differentiation. Which of the following molecules acts as the primary intracellular mediator for this pathway?

A patient with severe osteoporosis is treated with romosozumab. This medication primarily increases bone formation by targeting sclerostin. Which cellular pathway is directly upregulated as a result of this inhibition?

Sclerostin, a glycoprotein produced by mature osteocytes, regulates bone mass primarily by inhibiting which of the following molecular pathways?

According to Perren's strain theory, what is the maximum interfragmentary strain that permits the formation of lamellar bone via primary (direct) bone healing without the formation of a visible callus?

Which of the following intracellular signaling molecules is directly phosphorylated upon the binding of Bone Morphogenetic Protein-2 (BMP-2) to its cell surface serine/threonine kinase receptor?

Demineralized bone matrix (DBM) is commonly utilized as a bone graft substitute in spinal fusions. Which of the following combinations of properties best describes its specific biological activity?

During the resorption phase of bone remodeling, osteoclasts must firmly adhere to the bone surface. Which specific cell-surface integrin plays a critical role in forming the sealing zone necessary for effective bone resorption?

During the secondary healing of a fracture, intramembranous ossification occurs predominantly in which of the following specific microenvironments?

According to Perren's strain theory, what range of interfragmentary strain is required to promote secondary bone healing via callus formation?

Bone morphogenetic proteins (BMPs), specifically BMP-2 and BMP-7, initiate their intracellular signaling cascade primarily through which molecular pathway?

Romosozumab has recently been approved for the treatment of severe osteoporosis. What is the precise molecular target of this monoclonal antibody?

During bone resorption, osteoclasts create an acidic microenvironment in Howship's lacunae by secreting protons via a vacuolar H+-ATPase. Which enzyme is then primarily responsible for the degradation of the organic type I collagen matrix?

An adult sustains a transverse radius fracture and undergoes open reduction and internal fixation with a dynamic compression plate. If absolute stability and rigid compression are achieved, the fracture will heal via which mechanism?

Parathyroid hormone (PTH) plays a critical role in calcium homeostasis. At the cellular level within bone tissue, what is the primary direct action of PTH?

A nonunion of the tibia requires bone grafting. The surgeon desires a graft material that possesses osteoconductive, osteoinductive, and osteogenic properties simultaneously. Which of the following materials is the only one to fulfill all three criteria?