What determines the capabilities of a cell?

The capabilities of a cell are fundamentally determined by the genes it expresses. Gene expression refers to the process through which information from a gene is used to synthesize functional gene products, typically proteins. These proteins play critical roles in various cellular functions and processes, such as metabolism, signal transduction, and cell structure.

Each cell in a multicellular organism contains the same genetic material, but different cells can express different sets of genes, which leads to different cell types and functions. For example, muscle cells express genes that enable movement, while nerve cells express genes that allow for signal transmission. This ability to express specific genes according to the needs of the cell and its environment is what ultimately defines its capabilities.

Meanwhile, while the proteins present in a cell are indeed important for its functions, it is the underlying gene expression that dictates which proteins are produced and in what quantity. The number of organelles can influence a cell's efficiency in performing its tasks, but they do not determine the fundamental capabilities of the cell itself. Similarly, the age of the cell may impact its functionality and health, but it is not the primary determinant of what the cell can do in terms of biological processes and responses.