Every living thing is composed of cells. Whether human beings, animals, or even plants, billions and trillions of cells come together to make up the whole. Cells are mainly of two types – Prokaryotic cells, and Eukaryotic cells.
Prokaryotic cells make up micro-organisms like bacteria, while Eukaryotic cells make up plants and animals. Although plants and animals are made of the same type of cell (Prokaryotic), there are a ton of differences between plant cells and animal cells. One of such notable differences is the presence of a cell wall.
So Do Animal Cells Have A Cell Wall?
No, animal cells do not have a cell wall. While plants may possess cell walls, animals on the other hand do not. This is probably the most notable difference between plant cells and animal cells. For animal cells, the cell membrane takes the place of a cell wall. A cell membrane acts as the protective covering for animal cells but is softer, thinner, and more malleable than a typical cell wall.
What Is A Cell Wall?
A cell wall is the rigid nonliving permeable wall that surrounds the plasma membrane and encloses/supports the cell as a whole. Cell walls can only be found in plants, bacteria, fungi, and algae. You can think of a cell wall as the exoskeleton of a plant because the functions of a plant cell wall in a plant are similar to the functions of a skeletal framework in humans and animals.
Functions Of Plant Cell Wall
Cell walls in plants play some unique roles in plants, quite similar to the roles skeletons play in human bodies.
Maintain Cell Shape
Without cell walls, plant cells would lose their shape, and if the cells were shapeless, so too would the plants themselves become shapeless. This is quite similar to the way animal skeletons maintain a body shape. Without cell walls, plants won’t be able to stand and maintain their shape.
Provide Rigidity And Turgidity
Asides from giving shape to plants, cell walls also provide rigidity, turgidity, and hardness. Animals have bones and muscles that enable them to stand, but plants do not. For this reason, plants need a rigid network so that they can be solid/turgid enough to grow big, tall, and strong, as much as sunlight and nutrients allow.
Cell walls provide a sturdy, tight network that makes plants able to stand and be unbendable. The tougher/tighter the network, the more the plant is turgid and restricted from movement.
Hence, as a plant grows, its rigidity increases: As a young sprout it’s very tender, but by the time it becomes a full-blown tree it is practically immovable. This is because the cell walls have multiplied and matured to a very hard state.
A plant cell wall protects the plant from external damage. This you can easily tell by the hard bark every plant has. The more a plant grows, the tougher its cell walls become, leading to better protection (harder bark and all).
Plants are stationary living things and cannot defend themselves, so the cell wall is its natural defense mechanism. If plants only had cell membranes like animals, they would break/die easily.
Why Do Animal Cells Not Have A Cell Wall?
They Don’t Need It
The primary functions of a cell wall are to give shape, maintain rigidity and turgidity, and for protection: Taking a simple analysis will show that animals do not need a cell wall for all these.
Firstly, animals unlike plants, have bones. An animal’s shape is determined by the shape of its bones. So with this, having a cell wall would only complicate things. Plants have no skeletal framework whatsoever, hence the need for cell walls.
Secondly, animals have muscles and bones to provide all the rigidity and turgidity they need. Animals use their bones and muscles to stand upright and perform motor functions. Plants have no muscles to contract in other to provide turgidity, nor do they have bones; So cell walls are not necessary to animals the way they are to plants.
Thirdly, animals sense, feel, think, move, and react. As a result, they can protect themselves from an attack or threat. With this ability, there’s no need for an animal to have protection in its cellular structure.
Animals Are Mobile Creatures
One thing with a cell wall is that it causes rigidity and firmness in the living thing. Plants do not move, they don’t have to: but animals move and do all sorts of things. If animals were to have a cell wall, they too (just like plants) would be immobile.
This is why rather than having a rigid cell wall, animals have a soft, flexible cell membrane – This allows for movement, twisting & contortion, and all other things that animals do. Movement is vital for animals so they can search for food to eat, unlike plants that make their food via photosynthesis.
For Faster Regeneration
Cell membranes make for faster cell division and regeneration. Given the tough, impermeable nature of cell walls, cellular regeneration and division aren’t so easy. Cell walls consume a lot of energy during formation and division, and also have slower regeneration times.
Considering the fact that animals get injured easily from time to time, their cells need to be elastic and have faster regeneration time. Cell membranes allow for this, and also consume far less energy compared to cell walls.
Differences Between A Cell Wall And A Cell Membrane
|Cell Wall||Cell Membrane|
|Can only be found in plants||Present in all types of cells|
|It is the outermost layer of plant cells||It is the outermost layer of animal cells|
|Can measure from 0.1 micrometers to several micrometers||Can measure anywhere between 7 and 10 nanometers|
|Very thin and rigid||Very thin and delicate|
|They are metabolically inactive||They are metabolically active|
|Thickness grows as the plant gets older||Thickness never grows|
What Other Differences Exist Between A Plant Cell And An Animal Cell?
Besides the cell membrane and cell wall fiasco, several other differences exist between plant cells and animal cells:
1. Size: Animal cells are much smaller than plant cells. Animal cells measure between 10 and 30 micrometers while animal cells measure between 10 and 100 micrometers.
2. Cell wall: Animal cells only have a cell membrane, whereas plant cells have a cell membrane as well as a strong cell wall made from cellulose.
3. Shape: Plant cells have a fixed rectangular shape (due to their strong, well-defined cell walls). Animal cells on the other hand have irregular shapes since they only have a soft, permeable cell membrane.
4. Vacuoles: Vacuoles are the small cavities in cells that usually contain fluid. Animal cells always possess several tiny vacuoles, but plant cells only have a single, large vacuole.
5. Nucleus: The nucleus in animal cells is located at the center, while that of plants is located off-center (towards the side of the plant cell).
6. Energy: Animal cells store energy in the form of glycogen, while plant cells store energy in the form of starch.
7. Chloroplast: Plant cells have chloroplasts while animal cells do not. This chloroplast is what makes photosynthesis possible in plants.