1. Cell function: The shape of a cell is determined by the function it performs. Cells that move, for example, have a different shape than cells that are stationary.

2. Cell size: The size of a cell can also determine its shape. Smaller cells may have a rounder shape, while larger cells may be elongated or flattened.

3. Cytoskeleton: The cytoskeleton, made up of microfilaments, microtubules, and intermediate filaments, provides structural support to the cell and helps to maintain its shape.

4. Membrane proteins: Membrane proteins play a role in determining the shape of a cell, as they can attach to the cytoskeleton and help to anchor it to the cell membrane.

5. Extracellular matrix: The extracellular matrix, a network of proteins and carbohydrates that surrounds cells, can also influence cell shape.

6. Organelles: The shape of organelles within the cell can influence the overall shape of the cell.

7. Environmental factors: Environmental factors such as temperature, pH, and osmotic pressure can also affect the shape of a cell.