You could choose cells within the human body such as neurons or eosinophils or epithelial cells. You might choose plant cells such as collenchyma cells or xylem cells. You could also choose a fungal cell such as a hypha. Since some organisms only have one cell, you could also choose one of those to discuss.
What type of cell is it? What type of organism is the cell found in? Where in the organism is the cell found?
What is its function or duty? How does it contribute to the ability of the organism to maintain homeostasis? Describe the cell's characteristics.
Are there organelles? Does the cell contain components that are unique to that type of cell? Can the cell reproduce, if so, how does this occur? Is this type of cell found in other organisms?