An onion cell has a rectangular shape. An onion cell's size can range in length from 0.25 to 0.4 millimeters. An onion is a multicellular plant.
As a plant, the cells of an onion have organelles or components that include membrane walls, nuclei and cytoplasm. A plant cell also has a cell wall and a large vacuole. The function of a vacuole is to store fluid and solid materials. The cell wall is made up of cellulose.
There are some similarities and differences between plant and animal cells. One main difference is that animal cells have a round shape while plants cells are rectangular. Some similarities between the two are that each cell type has a nucleus, ribosomes and mitochondria.