Plant cells are the basic unit of life of plant organisms. They are eukaryotic cells, which have a true nucleus as well as specialized structures called organelles that carry out various functions. Plant cells have special organelles called chloroplasts, which make sugars through photosynthesis. They also have a cell wall that provides structural support.
Plant Cell Definition
“Plant cells are eukaryotic cells with a true nucleus, with specialized structures called organelles that perform certain specific functions.”
What is Plant cell?
Plant cell refers to any plant cell. Plant cells are believed to have evolved from early green algae and probably first occurred more than 500 million years ago, in the early Paleozoic era. Plant cells were first noticed by an English natural philosopher, Robert Hooke. With the availability of a microscope, he was able to see plant cells from a sample of a bottle cork. He noticed the subtle holes that looked like a hive. Then he coined the term cells to refer to these tiny pores.
Initially, they thought they were empty cells. With the availability of more advanced microscopes, scientists were able to observe the living components of plant cells. Typically, an ordinary plant cell has membrane-bound cell structures (called organelles) that are suspended in the cytoplasm.
Explanation of Plant Cell
Animals, fungi, and protists are composed of at least one eukaryotic cell. In contrast, bacteria and archaea are composed of a single prokaryotic cell. Plant cells are distinguished from cells of other organisms by their cell walls, chloroplasts, and central vacuoles.
Chloroplasts are organelles that are important for plant cell function. These are structures that perform photosynthesis, producing glucose using energy from the sun. In doing so, the cells use carbon dioxide, and they release oxygen.
Other organisms, such as animals, rely on this oxygen and glucose to survive. Plants are considered autotrophic because they make their own food and do not consume any other organism. In particular, plant cells are phototrophic because they use light energy from the sun to produce glucose. Organisms that eat plants and other animals are considered heterotrophic.
Other components of the plant cell, the cell wall, and the central vacuole, work together to stiffen the cell. The plant cell will store water in the central vacuole, which expands the vacuole in the sides of the cell. The cell wall then pushes against other cell walls, producing a force known as tugger pressure. While animals rely on a skeleton for structure, tugger pressure in plant cells allows plants to grow taller and reach more sunlight.
A typical plant cell structure includes organelles, cytoplasmic structures, cytosols, cell membranes (also called plasma membranes), and cell walls. Plant cell organelles include plastids, nuclei, mitochondria, endoplasmic reticulum, and the Golgi apparatus. The nucleus is the organ that controls the metabolic activities of the cell. It contains most of the genetic material in the cell.
Other genetic materials are found in semi-autonomous organisms, mitochondria, and chloroplasts. Mitochondria are organelles that provide chemical energy to cells, e. Yes. ATP by cellular respiration. Chloroplasts are chlorophyll-containing organelles that play an important role in the photosynthetic process. They are light energy (photon): cardiac organs. They convert inorganic salts, water, and carbon dioxide into complex organic matter (like glucose molecules), which is powered by light energy (such as sunlight) from a light source.
In addition to chloroplasts, other types of plastids are also found in plant cells. They are chromoplasts and leucoplasts. The chromoplast contains secondary dyes while the leucoplast contains accumulated food.
The endoplasmic reticulum is the organ involved in protein synthesis. Along with ribosomes, they form proteins that will be transported intracellularly or externally. Proteins pass to the Golgi apparatus for transport, where they are packaged and classified. Lysosomes, peroxisomes, and cytoskeletons (microtubules, actin filaments, and intermediate filaments) are also present in plant cells. A central vacuole is present and often has the largest cytoplasmic structure in a plant cell. Seeding is necessary because of its role in osmoregulation.
All of these cytoplasmic structures are suspended in the cytosol, the fluid component of the cytoplasm. Cell membranes include organelles, other cytoplasmic structures, and cytoles.
It is a semi-permeable, double membranous mantle composed of lipids, carbohydrates, and proteins. The outer part of the cell has a cell wall that is responsible for the turgidity, stiffness, strength, and resistance of the cell against mechanical stress.
A plant cell wall can be made up of two layers of cell walls, a primary wall, and a secondary wall. A primary cell wall contains cellulose, pectin, and hemicellulose. Over time, it can build up another layer called the secondary cell wall. Due to the lignin deposition, it is characteristically thick. For generalized plant cell models, see the description of plant cells.
Plant Cells vs. Animal Cells
Both Plant and animal cells are eukaryotic cells, meaning that they have a defined nucleus and membrane-bound organisms. They share cell membranes, nuclei, mitochondria, Golgi apparatus, endoplasmic reticulum, ribosomes, and many common features.
However, they have some obvious differences. First, plant cells have a cell wall that surrounds the cell membrane, whereas animal cells do not. Plant cells have two organelles that lack animal cells: chloroplast and a large central vacuole.
These extra organs allow plants to form an upright structure without the need for a skeleton (cell wall and central vacuole), and also allow them to make their own food through photosynthesis (chloroplasts).
Parts of Plant Cell
The plant cell has many different characteristics that allow it to carry out its functions. Each of these structures, called organelles, plays a special role.
Plant and animal cells share many common organisms, and more information can be found by visiting the “Animal Cell” article. However, plant cells have certain structures, including chloroplasts, a large vacuole, and cell walls.
Chloroplasts are specialized organelles found only in plants and some types of algae. These organs carry out the photosynthesis process, which converts water, carbon dioxide, and light energy into nutrients from which plants can receive energy. Some plant cells can contain more than one hundred chloroplasts.
Chloroplasts are disc-shaped organs surrounded by a double membrane. The outer membrane forms the outer surface of the chloroplast and is relatively permeable to small molecules, allowing substances to enter the organelle. The inner membrane is just below the outer membrane and is less permeable to external substances.
There is a thin intermembrane space between the outer and inner membranes that is approximately 10-20 nanometers wide. The center of the chloroplast, which is surrounded by a double membrane, is a fluid matrix called a stroma (it can be thought of as the cytoplasm of a chloroplast).
Inside the stroma, there are many structures called thylakoids, which look like flat discs. The thylakoids stack on top of each other in vascular plants called Grand. Thylakoids have a high concentration of chlorophyll and carotenoids, which are pigments that capture the energy of sunlight. The molecule is also chlorophyll, which gives plants their green color.
Plant cells are experts in the sense that they have a large central location. A vacuole is a small cell in a cell in the plasma membrane that may contain fluid, ions, and other molecules. The vacuoles are essentially large vesicles. They can be found in the cells of many different organisms. However, plant cells have a larger space, which can range from 90% to 30% of the total cell volume.
The central vacuole of a plant cell helps maintain its tugger pressure, which is the pressure of the cell material that pushes against the cell wall. A plant grows best when its cells are tall, and this occurs when the central vacuole is filled with water.
If the pressure in the plants decreases, the plants begin to dissolve. Plant cells are better in hypotonic solutions, where there is more water in the atmosphere than the cell. Under these conditions, osmosis causes the cell to water and multiply.
Animal cells can, by comparison, snatch if too much water is released; They do better in isotonic solutions, where the concentrations of solutes in the cell and the environment are the same, and the net velocities of water inside and outside the cell are the same.
Many animal cells also have vacuoles, but they are much smaller and perform less important functions.
The cell wall is a hard layer that is outside the plant cell that provides resistance and also maintains high rigidity. In plants, the cell wall consists mainly of cytoplasm, other molecules such as hemicellulose, pectin, and lignin. The structure of the plant cell wall separates it from the cell wall of other organisms.
For example, fungi contain chitin in the cell walls and peptidoglycan in the bacterial cell walls. These substances are not found in plants. Importantly, the main difference between plant and animal cells is that plant cells have a cell wall, while animal cells do not.
Plant cells have a primary cell wall, which is a flexible layer outside of a growing plant cell. A secondary cell wall can also occur in plants, when the cell matures, a thick, hard layer forms inside the plant’s primary cell wall.
The nucleus is a membrane-bound structure that is present only in eukaryotic cells. The important function of a nucleus is to store the DNA or hereditary information necessary for cell division, metabolism, and growth.
- Nucleolus: forms the protein-forming structures and ribosomes of the cell.
- Nucleopore: The nuclear membrane is punctured by holes called nucleoporins, through which proteins and nucleic acids pass.
They are membrane-bound organs that have their own DNA. To carry out the photosynthesis process, it is necessary to store starch. It is also used in the synthesis of many molecules that make up the building blocks of a cell. Here are some important types of plastids and their functions:
They are found in non-photosynthetic plant tissues. They are used for the storage of proteins, lipids, and starch.
It is a long limb surrounded by phospholipid membranes. The chloroplast is disk-shaped, and the stroma is the liquid within the chloroplast that contains spherical DNA. Each chloroplast has a green pigment called chlorophyll required for the photosynthesis process. Chlorophyll absorbs energy from sunlight and uses it to convert carbon dioxide and water into glucose.
It is about 30% of the volume of a cell in a mature plant cell. The tonoplast is a membrane that surrounds the central vacuole. In addition to storage, the important function of the central vacuole is to maintain Tughlaq pressure against the cell wall. Cell sap occurs in the central vacuole. It is a mixture of salts, enzymes, and other substances.
They are found in all eukaryotic cells that participate in the delivery of synthesized macromolecules to different parts of the cell.
They are the smallest membrane-bound organs that contain RNA and protein. They are sites for protein synthesis, therefore, also known as cellular protein factories.
They are double-membrane organelles found in the cytoplasm of all eukaryotic cells. They provide energy by breaking down carbohydrates and sugar molecules, making them also called the “Powerhouse of the cell.”
Lysosomes are called suicidal bags because they contain digestive enzymes in a bound membrane. They perform the removal of cellular debris by digesting clogged organelles, food particles, and foreign bodies in the cell.
Plant cells have many other organelles that are essentially similar to other types of eukaryotic cells, like organelles, like animal cells.
- The nucleus contains deoxyribonucleic acid (DNA), which is the genetic material of the cell. DNA contains the instructions for making proteins, which control all the activities of the body. The nucleus also controls cell growth and division.
- Proteins are synthesized in ribosomes, modified in the endoplasmic reticulum, and folded, classified, and packed into vesicles in the Golgi apparatus.
- Mitochondria are also found in plant cells. They produce ATP through cellular respiration. Photosynthesis in the chloroplast provides nutrients that break down the mitochondria for use in cellular respiration. Interestingly, both the chloroplast and the mitochondria are formed from bacteria bound by other cells in an endosmotic (mutually beneficial) relationship, and they did so independently of one another.
- There is liquid cytosol inside the cells. It is primarily made up of water and also contains ions, proteins, and small molecules. The cytosol and all the organisms within it, except the nucleus, are called cytoplasm.
- The cytoskeleton is a network of fibers and tubules found in the cytoplasm of a cell. It has many functions; It shapes the cell, imparts strength, stabilizes tissues, creates anchor organelles within the cell, and plays a role in cell signaling. The cell membrane, a double layer of phospholipids, surrounds the entire cell.
Plant Cell Types
Five types of tissue are formed by plant cells, each with different functions. Parenchyma, collenchyma, and sclerenchyma are all simple plant tissues, meaning they contain a single cell type. In contrast, xylem and phloem contain a mixture of cell types and are referred to as complex tissues.
- The parenchyma tissue represents most of the cells in a plant. They are found in the leaves and perform photosynthesis and cellular respiration along with other metabolic processes. They also store substances such as starch and protein and play a role in wound repair in plants. Parenchyma cells are tissue parenchymal cells. They have exceptionally thin walls (due to the absence of secondary wall deposition) and survive to maturity. They are mainly engaged in photosynthesis, food storage, secretion, and phloem loading. Parenchymal cells are the most common type of plant cell. They occur in vascular bundles, leaves, and epidermis. The parenchymal cells that participate in photosynthesis are called Collenchyma cells. Guard cells are another specialized type of parenchyma cell. They control the opening and closing of stomata (plant holes for gas exchange).
- Collenchyma tissue helps the growing parts of a plant. They are elongated, have thick cell walls, and can grow and change shape as the plant grows. Collenchyma cells are tissue cells from collenchyma. Like parenchyma cells, they also lack a secondary cell wall. They also often survive to maturity. However, they differ, despite having more primary cell walls than parenchymal cells, the wall thickness is uneven. Collenchyma cells are commonly found in growing shoots and leaves where they provide structural support.
- Sclerenchyma tissue consists of stiff cells that are the main supporting cells in growing areas of a plant. The sclerenchyme cells are dead and contain very thick cells. Sclerenchyma cells are sclerenchyma tissue cells. They are thick walls due to secondary walls and lignin deposits. Unlike parenchyma and Collenchyma cells, sclerenchyma cells are dead as they mature. They lose their protoplast. Examples of sclerenchyma cells are sclerenchyma fibers, sclereids, and mat fibers.
- Reproductive cells unlike animals, plants have a choice of generations, that is, alternative sporophyte and gametophyte phases. A sporophyte is a form of plant in the diploid state. This eventually produces spores that produce spores. A spore is a haploid reproductive cell involved in asexual reproduction and gives rise to a gametophyte. Each haploid spore divides mitotically to become a gametophyte. Therefore, a gametophyte is a form of plant in a haploid state. It tolerates gametangia that produce sex cells (gametes). Sex cells are reproductive cells that participate in sexual reproduction. The female sex cell is an egg, while the male sex cell is a sperm. These cells are haploid. Thus, when united, they form diploid zygotes. The zygote, then, becomes a new sporophyte.
- Xylem cells carry most of the water and some nutrients from the plant to the roots, stem, and leaves.
- Phloem cells carry nutrients created during photosynthesis to all parts of a plant. They transport SAP, which is a solution of water in sugars.
- Meristematic cells are cells of the meristem. These cells are not yet differentiated and actively divide by mitosis. They are plant stem cells, capable of giving rise to any type of plant.
Importance of Plant Cell
Plant cells are important as part of the biotic component of an ecosystem. They are the main producers on which non-autotrophic organisms depend as sources of nutrients and organic matter. Plant cells are also commercially important. Fibers (such as phloem fibers) are collected for their commercial value. They are marketed as jute, hemp, hemp, ramie, rattan, and kenaf. They also produce compounds that have medicinal and industrial value.