Gap junctions are absent in:
Gap junctions are absent in:
Select an option to attempt
Correct Answer: Option D
Explanation
Gap junctions and cell communication:Gap junctions are intercellular channels made of connexin proteins that allow direct cytoplasmic communication between adjacent cells, passing ions and small molecules up to ~1 kDa.Present in:• Brain cells (neurons and especially glia)• Cardiac muscle cells (essential for synchronised contraction via electrical coupling)• Hepatocytes (liver cells)Absent in:• Erythrocytes (red blood cells): They are enucleated, lack most organelles, and are terminally differentiated with no nucleus. They have no need for direct cell-to-cell communication and do NOT express connexins.Answer: Erythrocytes (Option 4).