Introduction
Plant and animal cells are Eukaryotic (they have a nucleus surrounded by a nuclear membrane). However, the reason their cell structure differ is that plants are producers (they can produce their own food, making them unique), and animals are consumers. Both have cell organelles like nuclei (which store genetic information), mitochondria (which aid in producing energy by breaking down sugar and other compounds), and so on.
Plant cells are the cells present in viridiplantae (green algae and land plants). A plant cell consists of a cell wall containing cellulose, which is used to distinguish them from the cells of fungi and bacteria. They contain plastids, the most prominent of which is chloroplast, which contains chlorophyll (green pigment). Chloroplast facilitates photosynthesis – a process that involves the absorption of carbon dioxide, sunlight, and water to produce food and oxygen.
Animal cells are the basic structural unit of animals. They have different shapes; some are round or oval, while others are flat. A cell membrane covers the animal cells, protecting the cells and regulating how the nutrients enter them. These cells have cytoplasm (a jelly-like substance) that is protected by the cell membrane. The substance protected by the nuclear membrane or nuclear envelope is referred to as nucleoplasm.
Plant Cell vs. Animal Cell
All plant cells have a rectangular shape. On the other hand, animal cells are round and irregular in shape. The cell membrane of plant cells has a wall (cell wall) that surrounds the cell membrane, whereas animal cells do not have cell walls. Plants have chloroplast, which aids in photosynthesis, whereas animal cells lack chloroplasts. They rely on cellular respiration (oxygen acts as an oxidizing agent and breaks down molecules to produce energy) to produce energy.
Difference Between Plant Cell And Animal Cell in Tabular Form
| Parameters Of Comparison | Plant Cell | Animal Cell |
| Shape | The chloroplast in plant cells facilitates photosynthesis, which results in energy production. | Animal cells have uneven forms (but typically, they are round). |
| Energy production | The chloroplast in plant cells facilitates photosynthesis which results in energy production. | Cellular respiration takes place to produce energy. |
| Centriole | Plant cells lack centrioles. | All animal cells have centrioles (organelles that help in determining the nucleus’ location and help in developing thread-like connective tissue). |
| Size | All plant cells are similar in size and range from 10 – 100 micrometers. | Animal cells come in varying sizes but are generally smaller than plant cells (10 – 30 mm). |
| Energy Storage | Plants store energy in the form of starch. | Animals store energy in the form of carbohydrate glycogen. |
| Vacuole | Plants have a single vacuole (which helps store water). | Animals have multiple small vacuoles (which help store water, ions, and waste). |
| Lysosomes | Plant cells do not contain lysosomes. | Animal cells have lysosomes that help in plasma membrane repair. |
| Plastids | Plastids such as chloroplasts are present in plant cells. | Animal cells lack plastids. |
| Cilia | Plants lack cilia. | Animal cells have cilia (hair-like structures that help fluids move past the cells. |
What Is A Plant Cell?
Plant cells are the basic units of plants with a nucleus bound by a membrane and organelles (specialized structures). Each plant cell has a central vacuole that regulates turgor pressure (pressure caused by fluids inside the cells) and supports the cell wall. If the vacuole shrinks, the cell wall loses its support/rigidity, and as a result, the plants look wilted.
Types Of Plant Cells
Parenchyma
These cells aid in the photosynthesis, storage, and transfer of cells and form the leaves of a plant. The cytoplasm of parenchyma cells facilitates nectar secretion (movement of sugar-rich liquid from one point to another). Those cells that are mainly involved in photosynthesis are referred to as Chlorenchyma cells. Moreover, they are living cells.
Collenchyma
Collenchyma cells have a wall made up of pectin and hemicellulose. These cells offer stretchable support to developing plants. Collenchyma cells initially resemble parenchyma cells, but the lack of plastids easily sets them apart from the latter. They become living cells only at the stage of maturity.
Sclerenchyma
Sclereids and fibers are the two types of sclerenchyma cells. They have a primary cell wall and a secondary thickened and lignified (lignin is crucial for the creation of cell walls and makes them rigid and less prone to rot) cell wall. Sclereids are tough, durable cells that provide grittiness to a plant’s leaves or fruits. The gritty walls of many fruits that protect the developing kernel inside are examples of Sclereids. They can also be found in apple cores. Fibers provide strength to leaves and stems and are used as materials for manufacturing many products.
Xylem
Xylem is a specialized water-conducting tissue that absorbs water and nutrients using the roots of the plant and conducts it to different parts of the plant. Mature xylem cells are dead; only the parenchyma cells in them are living cells. They help maintain a plant’s shape and prevent it from bending, as they support the plant’s weight and that of the water transported to the different parts.
Phloem
Phloem is a tissue that transports food, mainly sucrose (sugar made up of glucose and fructose), from the leaves of the plant to the rest of its parts. Sieve tubes and companion cells are the two types of phloem tissue. Sieve tubes facilitate the transfer of organic compounds produced during photosynthesis and lack nuclei and ribosomes. The smooth functioning of sieve tubes is ensured by companion cells which are a specialized form of parenchyma cells. Unlike sieve tubes, they have a large number of ribosomes. Bryophytes (mosses) lack phloem.
Epidermis
The epidermis is a single layer that shields the plants’ leaves, stems, and roots from the external environment. In addition, it regulates transpiration (loss of water through the portals/stomata in leaves). Various types of cells are present on this protective layer. Those cells control the rate of gas exchange, clothing hair (fine outgrowth on plants), and root hairs (they aid in better water absorption).
What Is An Animal Cell?
Animal cells ensure the proper functioning of an organism. The shapes of animal cells vary because of the lack of cell walls. Mitochondria (the cell’s powerhouse) aids in energy release. Animal cells have lysosomes that aid in the disposal of waste. They also help in destroying organisms that may harm the cells. The extracellular matrix (glycoproteins and protein collagen) bind the animal cells together and allows them to communicate with each other.
Types Of Animal Cells
Animal cells are of different types, and each type fulfills a certain purpose. The following are the major types of animal cells:
Stem Cells
Stem cells are the source of new cells that form tissues and organs, as they can develop into many different types of cells with specific purposes. Stem cell therapies are a popular solution to overcome the inability to regenerate tissues. Embryonic stem cells and adult stem cells are the major types of stem cells.
Embryonic stem cells are pluripotent. That is, they may develop and become any of the three germ layers – endoderm, mesoderm, and endoderm. They are derived from the inner cell mass of the blastocyst (a structure formed in the early embryonic stage). These stem cells have the ability to self-renew.
Adult stem cells are undifferentiated (do not have specialized structures). They multiply through cell division (the parent cell divides into two daughter cells). These stem cells replenish dying cells and aid in regenerating tissues. Adult stem cells are capable of self-renewing without losing their undifferentiated state.
Skin Cells
Skin cells, to no one’s surprise, make up the skin tissue. The skin cells of animals consist of keratinocytes, melanocytes, Merkel, and Langerhans. Keratinocytes form about 90% of the skin cells and produce keratin, which forms a protective layer of the body. Melanocytes are the second major type of skin cells and are responsible for an organism’s skin color. They form a layer under the keratinocytes, and the melanin they produce is transported to the top layer. The higher the melanin content, the darker the skin.
Muscle Cells
Muscle cells/myocytes/muscle fibers facilitate the movement of organs and limbs. Skeletal muscle cells, cardiac muscle cells, and smooth muscle cells are the types of myocytes. Skeletal muscle cells are responsible for conscious body movements, whereas cardiac muscle cells refer to the heart chamber walls’ cardiac muscle. Cardiomyocytes control heart contraction by generating electrical impulses. Smooth muscle cells cause skin hairs to stand erect when the animals feel cold or afraid (so, humans are not the only ones whose skin hair seems electrified when they are afraid).
Blood Cells
Blood cells can be either red or white blood cells. Red blood cells distribute oxygen to all parts of the body. Animal red blood cells lack nuclei; their volume remains constant throughout an organism’s lifespan. The red color of red blood cells or erythrocytes is due to the high hemoglobin content.
White blood cells boost the immune system and fight off any bacteria that affect an animal’s health adversely. Moreover, they defend an animal’s body from alterations of body tissue. White blood cells or leukocytes may be granular or agranular. Neutrophils, eosinophils, and basophils are granular leukocytes, whereas lymphocytes and monocytes are agranular leukocytes.
Nerve Cells
Nerve cells or neurons send and receive signals; that is, they help animals perceive a situation and act in response. The Sensory neurons receive cues/stimuli from the organism’s environment (for example, a hare registers the low growl of a wolf). The interneurons carry these stimuli to the brain and spinal cord (its brain registers that the wolf is about to attack). The motor neurons present in the brain and spinal cord send a signal to the body muscles instructing how to respond to the situation/stimuli (the hare feels the urge to flee, its muscles respond, and it takes off into safer parts of the woods).
Fat Cells
Adipocytes or fat cells are used to store energy in the form of fats or fatty acids and their derivatives (lipids). White fat cells and brown fat cells are the types of fat cells. They differ in the way they store lipids. White fat cells have a single lipid droplet (a cellular organelle that stores lipids) and so are unilocular. The fat is stored in a semi-liquid state in these cells, and the fat mainly consists of triglycerides (main constituents of body fat in vertebrates) and cholesterol ester.
Brown fat cells are multilocular, as they have multiple lipid droplets. Large amounts of mitochondria found in these cells are the reason for their brown color. Brown fat (or baby fat) aids in heat generation. An increase in adipocyte/fat cell size results in the expansion of fat mass, which leads to obesity.
Main Difference Between Plant Cell And Animal Cell In Points
- The cell walls in plant cells are the cause of their rigid shape; however, as animal cells lack them, they have varying shapes.
- Plant cells have chloroplasts that aid in photosynthesis, making plants the only beings in an ecosystem that can create their own food. On the other hand, the nerve cells of animals set them apart from plants, as they can perceive and react to the situation they find themselves in.
- Plant cells are generally larger than animal cells (they can be three times the size of a small animal cell).
- Plant cells have plastids and vascular tissues (xylem and phloem) that animal cells lack; however, the latter have lysosomes and centrosomes (a pair of centrioles form a centrosome).
- Plant cells have one large vacuole, whereas animal cells have several smaller vacuoles.
- Plant cells lack flagella and cilia, as they do not have centrosomes or centrioles that produce them. Animal cells have flagella and cilia.
Conclusion
Plant and animal cells, though similar, are easily differentiated when analyzed under microscopes. The presence of cell walls and plastids such as chloroplast clearly indicates that it is a plant cell. On the other hand, lysosomes, centrioles, and cilia can only be found in animal cells. Therefore, as long as people are familiar with important biological terms related to plant and animal cells, they will not have any difficulty identifying and differentiating the two.
References
- https://www.thoughtco.com/animal-cells-vs-plant-cells-373375
- https://en.wikipedia.org/wiki/Plant_cell
- https://www.geeksforgeeks.org/animal-cell/
- https://www.biologyonline.com/dictionary/animal-cell#
- https://en.wikipedia.org/wiki/Muscle_cell
- https://www.cliffsnotes.com/study-guides/biology/biology/nervous-coordination/animal-nerve-cells#
- https://en.wikipedia.org/wiki/Adipocyte
- https://en.wikipedia.org/wiki/Embryonic_stem_cells
- https://en.wikipedia.org/wiki/Adult_stem_cell#
- https://mmegias.webs.uvigo.es/02-english/guiada_a_sanguineo.php
