An animal cell can be comprised of anything from a single cell organism to a heart muscle cell in a human. While cells vary greatly in their abilities and functions, they all contain certain specific parts, known as organelles.
The cell membrane is the sac that the surrounds the entire cell. The cell's city wall, it is comprised of a phospholipid bilayer, that makes it waterproof, or "hydrophobic". There are also small protein openings which allow nutrients to pass in and out of the cell.
The nucleus is the brain of the cell. It contains the DNA instructions for every single function that the cell performs.
The centrioles bind together to form the microtubules of the cell. Similar to roads, these strands of hard protein proved structure and transportation for the cell's other organelles.
The ER provides the piping of the cell. It transports enzymes and chemicals essential for protein breakdown and the cell's overall maintenance.
Ribosomes are the factories of the cell, forming strands of protein to begin the process of protein synthesis. Without ribosomes, the cell would starve.
The Golgi Apparatus functions as a post office in the cell. It changes chemicals to make the useful to the cell, releases chemicals from its vesicles, stores harmful chemicals in its folds, and is believed to create ER.
Mitochondria are the powerhouse of a cell. They take strands of protein and combine it with the necessary chemicals to create pure energy. This process is known as cellular respiration.