The difference between a cell and an organelle is that an organelle is part of a eukaryotic cell. While a cell is typically considered to be the smallest self-contained part or independently functioning unit of an organism, organelles are smaller structures within eukaryotic cells that carry out various functions.
Eukaryotic cells are defined in part by the fact that they contain or are composed of various well-defined organelles, while prokaryotic cells lack organelles. The organelles are small structures within the cell that carry out different functions that contribute to the survival and functionality of the cell as a whole.
The types of organelles present in a cell vary by the type of cell. For example, chloroplasts, which are responsible for the process of photosynthesis, are present in plant cells, but not in animal cells. In addition to chloroplasts, some other common examples of organelles are the cell nucleus, ribosomes, mitochondria, vacuoles and Golgi bodies.
Each type of organelle carries out specialized functions or processes. The nucleus, for example, houses the cell's genetic information in the form of chromosomes and is responsible for cell division. The mitochondria produce energy that the rest of the cell needs to survive and contain genetic material specific to themselves and unique from the genetic material contained in the cell nucleus. Vacuoles, while having slightly different appearances in plant and animal cells, store energy, no matter which type of cell they are in.