The role of cytoplasm in a cell is to provide a medium where various cellular processes occur. It is a gel-like substance that fills the space between the plasma membrane and the nucleus. The cytoplasm contains organelles like ribosomes and mitochondria, which are vital for protein synthesis and energy production, respectively. Additionally, the cytoplasm helps to maintain the cell's shape, facilitates transport of materials within the cell, and supports biochemical reactions crucial for cell survival.