Difference Between Onion Cell and Human Cheek Cell

The main difference between onion cell and human cell is that the onion cell is a plant cell with a cell wall made up of cellulose whereas the human cheek cell is an animal cell without a cell wall. Furthermore, the onion cells are brick-like in shape while the human cheek cells are rounded. Moreover, the human cheek cells have a prominent nucleus as well.

Onion cell and human cheek cell are two types of epithelial cells with different origins. Both cells are observed during the primary observations through the light microscope.

Key Areas Covered

1. What is an Onion Cell
     – Definition, Microscopic Examination, Components
2. What is a Human Cheek Cell
     – Definition, Microscopic Examination, Components
3. What are the Similarities Between Onion Cell and Human Cheek Cell
     – Outline of Common Features
4. What is the Difference Between Onion Cell and Human Cheek Cell
     – Comparison of Key Differences

Key Terms

Cell Wall, Epithelium, Human Cheek Cell, Onion Cell, Vacuole

What is an Onion Cell

The onion cell is a plant cell that can be obtained by peeling off an onion. Onion cells exhibit a brick-like shape under the microscope. It has a cell wall, cell membrane, cytoplasm, nucleus, and a large vacuole. At the periphery of the cytoplasm, the nucleus is present. As the vacuole is prominent, it is present at the center of the cell. Cytoplasm surrounds the vacuole.

Figure 1: Onion Cells 

Cell wall serves as a protective barrier but, it allows the transmission of chemical signals and cellular excretions. The vacuole is a membrane-bound organelle that stores both solid and liquid contents.

What is a Human Cheek Cell

The human cheek cell is a type of animal cell and it can be obtained by scraping the cheek from a toothpick. It is made up of simple squamous epithelium. Since human cheek cells are animal cells they do not have a cell wall. Hence, the outside barrier of the human cheek cell is the cell membrane, which serves as the semi-permeable barrier. Unlike onion cells, human cheek cells have a dense cytoplasm. It is granular and occupies a large space within the cell. Also, human cheek cell has several, small vacuoles. A prominent nucleus is found at the center of the cell.

Figure 2: Human Cheek Cells

Human cheek cell also has other organelles such as mitochondria, Golgi, ER, ribosomes, and plastids.

Similarities Between Onion Cell and Human Cheek Cell

• Onion cell and human cheek cell are two types of epithelial cells observes under the light microscope.
• Both cells are easy to obtain. Both are in a single layer.
• Both are transparent.
• Both have a cell membrane, cytoplasm, nucleus, mitochondria, Golgi apparatus, ER, ribosomes, lysosomes, and plastids.
• Both cells do not have chloroplasts.

Difference Between Onion Cell and Human Cheek Cell

Definition

Onion cell refers to a clear epidermal cell that exists in a single layer in the onion fruiting body (bulb) while human cheek cell is a cell that belongs to the epithelial tissue of the lining of the oral cavity of humans.

Origin

Onion cell is a plant cell while human cheek cell is an animal cell.

Shape

Onion cell has a brick-like, more regular shape while human cheek cell has a rounded shape.

Cell Wall

Onion cell has a cell wall made up of cellulose while human cheek cell does not have a cell wall.

Nucleus

Onion cell has a small nucleus while human cheek cell has a large, prominent nucleus.

Vacuole

Onion cell has a large vacuole while human cheek cell may have several, small vacuoles.

Function

Onion cell serves as a protective layer against viruses and fungi while human cheek cells protect the underlying structures.

Slide Preparation

Onion cells can be peeled off from an onion while human cheek cells can be scraped off from the inner oral cavity with the use of a toothpick.

Conclusion

Onion cell is a plant cell with a cell wall and a large vacuole. On the other hand, human cheek cell is an animal cell with a prominent nucleus. Onion cells are brick-like in shape while human cheek cells are rounded. Human cheek cells do not have a cell wall or a large vacuole. Both onion and human cheek cells are epithelial cells. The main difference between onion cell and human cheek cell is the shape and the structure of each type of cells.

Reference:

1. “Onion and Cheek Cells.” Class 10 : Chemistry : Amrita Online Lab, Available Here

Image Courtesy:

1. “Onion Cells” By kaibara87 – http://www.fotopedia.com/items/flickr-3839720754, https://www.flickr.com/photos/kaibara/3839720754/ (CC BY 2.0) via Commons Wikimedia    
2. “Cheekcells stained” By Mulletsrokk – Own work (CC BY-SA 3.0) via Commons Wikimedia