Plant and animal cells have many similarities, but they differ in several ways, too. Although there are a number of ways in which they diverge, three key features differentiate cells from the plant and animal kingdoms.
Animals lack many of the features of cell anatomy that plants possess and are required to hunt, gather or scavenge for food; find mates (in many cases) for sexual reproduction; and engage in other life-sustaining activities that plants do not perform. The differences between the two cell types are a fundamental part of what make animals and plants what they are.
TL;DR (Too Long; Didn't Read)
There are many similarities between plant and animal cells, as well as three key differences. Both kinds of cells are eukaryotic, which means that they are larger than bacteria and microbes, and their processes of cell division make use of mitosis and meiosis.
Unlike animal cells, plant cells have cell walls and organelles called chloroplasts. Plant cells also have a large central vacuole, while animal cells either have small vacuoles or none. These differences result in functional differences, such as plants' ability to get energy from the sun instead of from organic matter.
Similarities Between Plant and Animal Cells
Both plant and animal cells are eukaryotic. The highest rank of biological taxonomy is called a domain. In other words, all living organisms can be grouped into three domains:
All multicellular organisms in the five kingdoms are in the Eukarya domain, including all plants and animals. Unlike their smaller single-celled counterparts, the prokaryotes in the Archaea and Bacteria domains, eukaryotes have a nucleus enclosed by a nuclear membrane as well as other membrane-bound organelles. In addition, their processes of cell division occur via mitosis and meiosis, rather than binary fission.
|Animal Cell||Plant Cell|
|Cell Wall||No||Yes (made of cellulose)|
|Vacuole||Either none or a few very small throughout the cell||One very large also called the “central vacuole”|
|Mobility||Can be mobile and fluid||Not mobile or fluid|
Most of the similarities between plant and animal cells have to do with the many organelles they share. In addition to both having membrane-bound nuclei, organelles that exist in both plant and animal cells include:
- Endoplasmic reticulum
- Golgi apparatus
Specialized Organelles: Chloroplasts
Chloroplasts are present in plant and algae cells, but not in animal cells (although various researchers are attempting to create “plantimals” by injecting chloroplasts into the embryonic cells of zebra fish and other species).
Chloroplasts contain chlorophyll, which is important for photosynthesis. Plants use photosynthesis to derive energy from sunlight. Plants are called autotrophs because they produce their own food from sunlight. Animals and other heterotrophs rely on organic matter to survive.
Chloroplasts have their own DNA and are very similar to prokaryotic bacteria; scientists believe that 1.5 billion years ago, chloroplasts may have been prokaryotic bacteria, living inside of algae. This is known as an endosymbiotic relationship. Over time, the prokaryotes became chloroplasts within the eukaryotic cells, and these cells gave rise to many species of algae and later, to plants.
A vacuole is another organelle. Plant cells tend to have one large central vacuole, but animal cells either have a scatter of small vacuoles or none. The vacuole is a large, membrane-bound sac that serves numerous functions, especially to provide storage of certain substances.
This organelle is vital to plants for a few reasons. Notably, the vacuole stores sugars to increase the flow of water into the cell by osmosis, increasing the turgor pressure in the plant cell. Greater turgor pressure means it is more rigid, which helps the plant to hold its structure.
Vacuoles are also able to store nutritious substances to save for later, or waste chemicals that the plant needs to excrete but is unable to. Vacuoles can even store toxins for self-defense against herbivores.
The Cell Wall
Plant cells do not move; they become fixed in place with cell walls, which are composed of many substances, particularly cellulose. Unlike plant cells, animal cells only have a plasma membrane, and no cell wall.
One benefit of cell walls has to do with the increased turgor pressure caused by vacuoles. Without cell walls, plant cells would continue to absorb water by osmosis until they burst, but the rigid cell walls place a limit on how much water can be absorbed.
Cell walls also provide cell structure and rigidity to the plant as a whole. This kind of rigidity would prevent animals from moving sufficiently. The cell wall also uses chemicals in its various layers to protect the cell from attacks, and to signal other cells to launch a defense.
Differences Between Plant and Animal Cells
The differences between plant and animal cells cannot the naked eye. However, the impacts of these differences on the morphology (form and features) of plants and animals is noticeable. Without chloroplasts, a cell wall and a central vacuole, animals cells are able to do certain things that plant cells cannot, and vice versa.
As connected units, such as body tissue, animal cells are able to allow for more fluid movement than plant cells, which are stiffly attached to their neighbors by cell walls. As individual units, animal cells are also able to move freely about the organism when necessary, or switch roles to specialize in another task. Plant cells are less able to do this because of the plant cell walls keeping them in place.
What plant cells (and plants) lose in physical freedom from cell walls and central vacuoles, they gain in self-reliance and security. Cell walls, central vacuoles and chloroplasts all contribute to plant cells' autotrophism, which frees them from reliance on the need for organic matter for nutrition. Plants do not need to scavenge, hunt or or forage for food. While animals battle for resources and engage in sexual reproduction, plants stay rooted and grow toward the sun.
About the Author
Rebecca E. received a degree in human development before attending graduate school in writing. She has an extensive background in cognition and behavior research, particularly the neurological bases for personality traits and psychological illness. As a freelance writer, her specialty is science and medical writing. She's written for Autostraddle, The Griffith Review and The Sycamore Review.