Which of the following is not a characteristic of the cell at the arrow?

Which of the following is not a characteristic of the cell at the arrow?

• A. It Is Multinucleated
• B. It Is a Macrophage
• C. It Breaks Down Bone
• D. It Is an Osteoblast

Answer: (D)

The key idea is bone remodeling cells and how they differ. The cell shown is multinucleated and resembles a macrophage, which fits osteoclasts—cells that resorb bone during remodeling. Osteoclasts are large, fuse from precursor cells, and create a sealing zone to secrete acid and enzymes that dissolve mineral and organic matrix. In contrast, osteoblasts are single-nucleus cells that build bone by producing osteoid and mineralizing it. Because the cell pictured is the bone-resorbing type, saying it is an osteoblast is not a characteristic of this cell.

The key idea is bone remodeling cells and how they differ. The cell shown is multinucleated and resembles a macrophage, which fits osteoclasts—cells that resorb bone during remodeling. Osteoclasts are large, fuse from precursor cells, and create a sealing zone to secrete acid and enzymes that dissolve mineral and organic matrix. In contrast, osteoblasts are single-nucleus cells that build bone by producing osteoid and mineralizing it. Because the cell pictured is the bone-resorbing type, saying it is an osteoblast is not a characteristic of this cell.