This document describes the structure and components of cells. It discusses the key parts of eukaryotic cells including the cell membrane, cytoplasm, and nucleus. The cell membrane is a phospholipid bilayer that maintains cell shape and allows for transport. The cytoplasm contains organelles like the endoplasmic reticulum, Golgi apparatus, mitochondria, and lysosomes that carry out important functions. The nucleus houses genetic material and controls cell activities.