In all living things, the cell is the basic unit of life. Just like people and animals, plants are made up of many cells. The plant cell is surrounded by a cell wall, which helps the plant cell keep its shape. Besides the cell wall, there are other parts of the cell called organelles that do different things. Let’s take a close look at the plant cell parts and their functions.
Plant Cell Definition
Plant cells are eukaryotic cells with a real nucleus and specialised structures called organelles that perform certain functions. Plant cells are eukaryotic cells, but they differ from the cells of other organisms in several basic ways. An animal cell’s nucleus and other organelles are comparable to those found in a plant cell. Cell walls, which are found on the exterior of plant cells, are one of their defining characteristics.
Plant Cell Diagram
When compared to animal cells, plant cells are larger and more rectangular in shape. Plant cells are very different from animal cells despite their eukaryotic origins and the fact that they share several cell organelles. Looking at the cells with an electron microscope helps to make sense of some of the differences.
Figure 1: Labelled Image Of Plant Cell
Plant Cell Structure
Plant cells are made up of different parts called cell organelles that help the cell meet its different needs to stay alive. Some of these parts are:
1. Cell Wall
This hard layer is composed of the polysaccharides cellulose, pectin, and hemicellulose. It is found outside the cell membrane. It also contains polymers such as lignin, cutin, and suberin, as well as glycoproteins. The cell wall’s primary functions are to protect and support the cell. The plant cell wall also contributes to the cell’s shape and structure while protecting it from mechanical stress. It also filters molecules as they enter and exit the system. Microtubules direct the development of the cell wall. It is divided into three layers: the middle lamella, the secondary lamella, and the primary lamella. To build the main cell wall, enzymes deposit cellulose.
2. Cell Membrane
A semipermeable membrane is part of the cell wall. It is made up of a thin layer of protein and fat. The cell membrane is a key part of how molecules get into and out of the cell. For example, the cell membrane moves food and important minerals while keeping out harmful substances.
The nucleus is a structure that is surrounded by a membrane and is only found in eukaryotic cells. The main job of a nucleus is to store the DNA or genetic material that is needed for the cell to grow, divide, and use energy.
# Nucleolus: Nucleolus is the nucleolus that generates ribosomes and other cellular protein factories.
# Nucleopore: There are slits in the nuclear membrane called nucleopores that let proteins and nucleic acids pass through.
Plasmids are membrane-bound organelles that carry DNA. They’re needed for processes like photosynthesis and starch storage. It is also used as a precursor to other chemicals that are fundamental biological components. An overview of the various types of plastids and the functions they provide is provided below.
# Leucoplasts: Leucoplasts are found in non-photosynthetic tissue of plants. They are used to store carbohydrates, fats, and proteins.
# Chloroplasts: It is an expanded organelle surrounded by a phospholipid membrane. The stroma, the fluid contained within the disc-shaped chloroplast, carries circular DNA. Chlorophyll, a green pigment required for photosynthesis, is present in each chloroplast. Chlorophyll absorbs the sun’s light energy and uses it to transform water and carbon dioxide into glucose.
# Chromoplasts: They are a type of coloured, heterogeneous plastid that makes and stores pigment in photosynthetic eukaryotic organisms. Chromoplasts contain red, orange, and yellow pigments that give ripe fruits and flowers their colours.
5. Central Vacuole
It takes up about 30% of the space in an adult plant cell. Around the core vacuole is a membrane called the tonoplast. Besides storing things, the main job of the central vacuole is to keep the turgor pressure on the cell wall. The centre of the body is full of cell sap. It contains salts, enzymes, and other chemicals.
6. Golgi Apparatus
They are found in all eukaryotic cells and move the macromolecules that have been made to different parts of the cell. The Golgi body is made up of five to eight cisternae, which are cup-shaped groups of compartments. The Golgi apparatus is made of flattened, disk-shaped pouches that are stacked on top of each other. A Golgi stack has between 4 and 8 cisternae most of the time. 40 to 100 stacks of cisternae are present in each mammalian cell.
They are the smallest membrane-bound organelles with protein and RNA. Since they serve as the sites for protein synthesis, they are also known as the cell’s protein factories. Both prokaryotic and eukaryotic cells include specialised organelles called ribosomes. Ribosomes are crucial for protein synthesis in all living cells. This cell organelle binds to messenger ribonucleic acid (mRNA), which carries information that is decoded by the mRNA’s nucleotide sequence. Transfer RNAs (tRNAs) containing amino acids are introduced at the acceptor site of the ribosome. After attachment, it continues to add amino acids to the growing protein chain of the tRNA.
These double-membrane organelles can be found in the cytoplasm of all eukaryotic cells. Mitochondria have earned the nickname “Powerhouse of the Cell” due to their role in converting dietary sugars and carbohydrates into usable energy. Most of the metabolic actions necessary for cellular respiration take place in the mitochondria.
Lysosomes have earned the nickname “suicidal bags” due to the digestive enzymes they carry within their membrane-bound structure. They are responsible for removing cellular waste from the body by decomposing old food, foreign items, and worn-out organelles. In plants, the vacuoles serve the same purpose as lysosomes.
Plant Cell Types
To ensure their survival, higher and more developed plants develop specialised cells. Some plant cells move water and nutrients around, while others are in charge of food storage. Specialized plant cells include parenchyma, sclerenchyma, collenchyma, xylem, and phloem. As an illustration of the wide variety of plant cells, consider the following:
1. Collenchyma Cells
When the growth of a plant is restricted because there is not enough hardening agent in the major walls, these hard cells, also known as stiff cells, play an important function in the plant’s support.
2. Sclerenchyma Cells
There is a hardening chemical present, making these cells stiffer than collenchyma cells. These cells are widespread in plant roots and play a crucial role in the plants’ structural integrity.
3. Parenchyma Cells
Parenchyma cells are essential to the functioning of all plants. They are the living cells of the plant and they contribute to the formation of the leaves. They also participate in cellular metabolism, food production, organic material storage, and gas exchange. They are more flexible than other cells because of their reduced thickness.
4. Xylem Cells
Xylem cells are the cells that are responsible for transport in vascular plants. They contribute to the movement of minerals and water up the plant, from the roots to the leaves and other parts of the plant.
5. Phloem Cells
Phloem cells are the name given to the other type of transport cell found in vascular plants. They distribute the nutrients that the leaves have prepared to the other parts of the plant.
FAQs on Plant Cell Parts and Their Functions
Collenchyma Cells, Sclerenchyma Cells, Parenchyma Cells.
Plant cells have specialized organelles such as chloroplasts, a cell wall, plastids, and a large central vacuole.
The cell wall is made up of a network of cellulose micro fibrils and cross-linking glycan’s that are embedded in a matrix of pectin polysaccharides that are highly cross-linked.
Photosynthesis happens in the chloroplasts of plant cells. Chlorophyll is a green pigment, and chloroplast is made up of it. The light reactions happen in the thylakoids of the chloroplast, which are made up of the pigment chlorophyll.
Most of the space in plant cells is taken up by a huge central vacuole, which contributes to their overall size. A vacuole is an organelle that is often absent in animal cells.