Plant Cell – Everything about Plant Cell
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Cells are the fundamental units of life. All living organisms are composed of cells, which are needed for normal function. According to scientists, cells provide structure and stability, but they also provide energy to an organism. Cells are so small that they cannot be seen without magnification.
There are two primary types of cells known to exist. They are eukaryotic and prokaryotic cells. Animals, plants and fungi are the best examples of organisms that include eukaryotic cells. So, the cell is the simplest unit of life, while the plant cell represents the crucial element for the existence of life. There are numerous interesting facts you should know about plant cells. Below you can read some of them.
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A plant cell is the structural and functional unit for all plant organisms.
There are millions of cells in an organism.
A plant cell is extremely small. It is only visible on a microscope.
As already mentioned, a plant cell can be included in the category of eukaryotic cells. These are the cells that have a well-defined nucleus.
There are some important differences between plant and animal cells. However, there are also some similarities worth to be known.
Plant cells have unique features that facilitate the process of photosynthesis. Through photosynthesis sunlight, water and carbon dioxide are transformed into energy, water and oxygen. This is an important process for the support of all forms of life.
The main function of a plant cells is to carry all processes that are needed to facilitate plant life.
The structure of the plant cell includes cellulose, chloroplasts, chlorophyll and vacuoles. Plasma membrane, nucleus, nucleolus and mitochondria are also included in the structure of a plant cell. The endoplasmic reticulum, Golgi apparatus and microtubules are other features of the plant cell.
Both plant and animal cells include nucleus, cell membrane and mitochondria, which are part of their structure.
There are two types of reproduction in plants. They can be asexual, when the cell splits in two, and sexual, when two cells combine to create one living cell.
Plant cells have cell walls in which they can store water.
Cell walls of plants are made up of cellulose, hemicellulose and pectin.
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So, there are both similarities and differences between plant and animal cells. They are both basic units of life, which compose all living organisms. However, plant and animal cells may have a different function and a different structure.
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All plant cells are characterized by several common features, such as chloroplasts, a cell wall, and a large vacuole. These features also differentiate plant cells from animal cells. In addition, there is a number of specialized types of plant cells that are found only in vascular plants. These include parenchyma cells, collenchyma cells, and sclerenchyma cells.
1. Parenchyma cells
The term parenchyma is derived from the Greek word para, which means “beside”, and en + chein, meaning “to pour in”. Parenchyma cells are the biochemistry machines of the plant. They are usually described as the typical plant cell, because they are not very specialized. These cells are commonly found in leaves, roots, and stems, usually having a spherical shape with only primary cell walls and highly functional cytoplasm.
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Parenchyma cells play an important role in food storage, photosynthesis, and aerobic respiration, meaning that they synthesize and store organic products in the plant and are the place where most of the plant’s metabolism takes place. These cells are alive at maturity and are responsible for a wide range of biochemical processes. Most parenchyma cells have the ability to differentiate into other cell types under special conditions
2. Collenchyma cells
The term collenchyma is derived from the Greek word kola, meaning “glue”. Collenchyma cells have a support function in plants, particularly in young plants. They help to support plants while not restraining growth due to their lack of secondary walls and the absence of a hardening agent in their primary walls. This means that their main function is to provide support for parts of the plant that are still growing, such as the stem.
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Collenchyma cells form strands or continuous cylinders just below the surfaces of stems or leaf stalks. They are similar to parenchyma cells in the sense that they are alive at maturity. To better understand what collenchyma cells do, imagine a stretchable support, without elastic snap-back.
3. Sclerenchyma cells
The term sclerenchyma is derived from the Greek word skleros, which means “hard”. Sclerenchyma cells are the ones providing rigid support for the plant, because they have a hardening agent and are much more rigid. These cells develop an extensive secondary wall that is invested with lignin (the main chemical component of wood), making it extremely hard. Besides support, sclerenchyma cells have other functions, which include discouraging herbivory, and conduction.
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There are two types of sclerenchyma cells – fiber and sclereid. Fiber cells are long, slender cells that usually form strands or bundles. Sclereid, also known as stone cells, occur singly or in groups and have various forms. Most sclerenchyma cells are dead cells at maturity. Sclerenchyma cells cannot survive for long because lignin also makes the wall waterproof, therefore making it impossible for the cells to exchange materials long enough for active metabolism.
These are the main and most important types of specialized plant cells. Other specialized plant cell types include xylem, phloem, and epidermis cells.
Plants have a wide variety of mechanical properties that may inspire engineers to design new materials.
Lorna Gibson, the Matoula S. Salapatas Professor of Materials Science and Engineering at MIT says:
‘If you look at engineering materials, we have lots of different types, thousands of materials that have more or less the same range of properties as plants. But here the plants are, doing it arranging just four basic constituents. So maybe there’s something you can learn about the design of engineered materials.”
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Engineers claim that some plants such as bamboo, maples, palm trees or potatoes inspire them, being a great example of precise engineering on a microscopic scale.  The way their cell walls are arranged and what they’re made of, some plants may be sturdy as an oak, while others as flimsy as a reed.
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To Lorna Gobson, many cell walls’ components resemble certain manmade materials such as cellulose, hemicellulose, which can be strong and stiff as manufactured polymers. Additionally, cells in woods are aligned similarly to engineering honeycombs, while polyhedral cell configurations found in apples look like industrial foams.
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Gibson researched plants’ natural mechanics and focused on three main plant materials: oak, cedar and woods, parenchyma cells found in root vegetables and fruits and coconut trees. She and other scientists studies these plants and their cells and analyzed two main mechanical properties in each plant: strength and stiffness.
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Plants are multicellular, eukaryotes organisms. They have membrane-bound organelles. A plant cell has a rigid cell wall, a central vacuole, plasmodesmata and plastids, which make it unique among all other type of eukaryotes cells. Plant cells sustain the photosynthesis process, during which oxygen is produced.
Plant cells are formed by different parts. All of them play an important role in the proper function of the cell.
1. Cell membrane
The cell membrane allows waste material to exit the cell. The membrane surrounds the cytoplasm of the cell. It actually forms a barrier between the inside of the cell and the outside area. The cell membrane regulates the movement of materials into and out of the cell. Having under consideration its function, the cell membrane is believed to be in a way similar to the skin.
2. Cell wall
The cell wall surrounds the cell. This is a rigid layer placed externally to the cell membrane. It offers structural support and protection to the entire cell. The cell wall also controls the amount of water that enters the cell. It allows the circulation of minerals and nutrients. The cell wall has the ability to sense the presence of pathogenic microbes, as well, being able to control the development of tissues within the cell.
3. Plasmodesmata
Plasmodesmata are microscopic channels of plants traveling the cell walls. It enables communication within the cell.
4. Tonoplast
The tonoplast surrounds a vacuole. Vacuoles are found in the cytoplasm, being membrane-bound compartments with storage functions.
5. Plastids
Plastids are some of the most important parts of the plant cell. They are responsible with photosynthesis, storage and synthesis.
6. Golgi Complex
Golgi complex is an organelle found in plant cells. It processes macromolecules, including proteins and lipids.
7. Chloroplast, Leucoplast, Chromoplast
Chloroplasts are organelles that conduct photosynthesis. They absorb light. Leucoplasts are plastids that are non-pigmented. Chromoplasts are plastids with role in pigment synthesis and storage.
8. Ribosome, Lysosome
Ribosomes are complexes of RNA and protein. Lysosomes are organelles which contain digestive enzymes.
9. Mitochondrion, Microtubule, Microfilament, Microbody
Mitochondrion is a membrane-enclosed organelle. Microtubules are components of the cytoskeleton. Microfilaments are the smallest filaments of the cytoskeleton. Microbodies are organelles of a globular shape.
10. Cytoplasm, Nucleus, Nuclear envelope
The cytoplasm is a semi-transparent fluid which fills cells. The nucleus contains the cell’s genetic material. The nuclear envelope is formed by two cellular membranes.
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Besides the aforementioned plant cell parts, DNA, chromatin and RNA should also be presented. DNA is the nucleic acid that contains genetic information, chromatin is a complex of DNA and protein, while RNA has an important role in translating genetic information from DNA to proteins.
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Most cells are not visible with the naked eye. However, with microscopes of various types, plant cells can be readily viewed and studied. In young parts of plants and fruits, cell shapes are generally round, while in older sections, the cells are somewhat boxlike with up to 14 sides as they become packed together.
A cell, regardless if it belongs to a plant, animal or human, is generally defined as the structural and functional unit of life. Think of your school building. Each building is made up a number of classrooms. Each classroom has four walls. Each wall is made of bricks. Each brick is the smallest unit of your school building.
There are structural and functional differences between plants and animals. These are manifested in the form of plant cell and animal cell differences.
Plant Cell Diagram