Plant Cell: Definition, Structure, Function, Diagram & Types

Plant cells are eukaryotic cells that have a true nucleus with specialized structures, known as organelles, which carry out distinct functions. Simply, they have different cell organelles along with a true nucleus for carrying out various cell functions. The main difference between a plant cell and an animal cell is the presence of a cell wall in plant cells which provides it with a definite shape. Cell walls are composed of cellulose and provide various structural and mechanical processes. Plant cells contain a plastid called chloroplasts which helps in photosynthesis.

Check More: Cell Membrane and Plasma Membrane

Key Terms: Plant Cell, Chloroplast, Photosynthesis, Eukaryotic Cell, True Nucleus, Xylem, Phloem, Collenchyma, Eukaryotic Nucleus, Cell Wall, Cell Membrane,

What is a Plant Cell? 

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Plant cell is a basic unit of a plant that consists of various cell organelles. Plant cells are eukaryotic cells that have a true nucleus with specialized structures, known as organelles, which carry out distinct functions. The main difference between a plant cell and an animal cell is the presence of a cell wall, cell membrane and chloroplast.

Plant Cell Diagram

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Plant cells are rectangular in shape and bigger than animal cells. Despite the fact that plant and animal cells are both eukaryotic and share a few cell organelles, plant cells perform different activities when compared to animal cells. Plant cells can be easily seen when viewed under an electron microscope.

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Parts of a Plant Cell 

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Plant cells, like other organs in the body, include a variety of components called cell organelles that perform diverse activities in order to keep the plant alive. Among these organelles are:

Cell Wall

• Outside the cell membrane, the plant cell wall is a strong layer made up of cellulose, glycoproteins, lignin, pectin, and hemicellulose.
• Proteins, polysaccharides, and cellulose make the plant cell wall.
• The cell wall's principal role is to defend and provide structural support to the cell, as well as to shield the cell from mechanical stress and to give it form and structure.
• The cell wall also serves as a filter for chemicals entering and exiting the cell.
• Microtubules, which are made up of three layers: primary, secondary, and middle lamella, guide the development of the cell wall.
• Enzymes lay down cellulose to form the main cell wall.

Cell Membrane

• Cell Membrane is a semi-permeable membrane found inside the cell wall.
• Cell membrane is made up of a thin coating of fat and protein.
• The cell membrane is responsible for controlling the entry and exit of particular chemicals into and out of the cell.
• The cell membrane, for example, prevents poisons and foreign material from entering the cell while allowing nutrients and vital minerals to pass through.

Nucleus

• Eukaryotic cells have a membrane-based organelle called the nucleus.
• Eukaryotes have a single nucleus in general, although certain cell types, such as human red blood cells, have no nuclei, while others, such as osteoclasts, contain many nuclei.

1. Nucleolus: Nucleolus aids in the production of protein-making structures and ribosomes in cells.
2. Nucleopore: Nucleopore are holes in the nuclear membrane that allow proteins and nucleic acids to flow through.

Cell Nuclues

Plastids

• Plant and algal cells include plastids, which are double-membrane organelles.
• These plastids are essential in the production and storage of food.
• Plastids frequently include pigments that are utilized in the photosynthesis process.
• These pigments can also alter the cell's color.
• Some important plastids are given below:

1. Leucoplasts: They're present in non-photosynthetic plant tissues. Protein, fat, and starch are all stored in these cells.
2. Chloroplasts: It is a Phospholipid membrane-enclosed elongated organelle. The stroma is the fluid within the chloroplast that contains circular DNA, and the chloroplast is structured like a disc. A green pigment called chlorophyll is found in each chloroplast and is necessary for photosynthesis. Chlorophyll takes light energy from the sun and converts it to glucose from carbon dioxide and water.

Chromoplasts

In photosynthetic eukaryotic organisms, they are diverse, coloured plastids that are responsible for pigment production and storage. Chromoplasts contain red, orange, and yellow pigments that give mature fruits and flowers their color.

Central Vacuole

• The central vacuole is a cellular organelle present in plant cells.
• It is frequently the cell's biggest organelle.
• It is encased in a membrane and serves as a storage facility for both supplies and trash.
• It also helps to maintain correct pressure by giving the developing plant proper structure. In a mature plant cell, it absorbs around 30% of the cell's volume.

Golgi Apparatus

Golgi apparatus are present in all eukaryotic cells and are responsible for transporting produced macromolecules to different regions of the cell.

Golgi Apparatus

Ribosomes

• Ribosomes are macromolecular machines that are found in nearly all live cells and are responsible for the production of biological proteins.
• As a result, ribosomes are often known as the cell's protein manufacturers.

Mitochondria

• ​Mitochondria are double-membrane organelles present in the cytoplasm of all eukaryotic cells that produce energy by breaking down glucose and sugar molecules.
• Mitochondria is also called the "Powerhouse of the Cell."

Lysosome

• Lysosomes contain digestive enzymes in a confined membrane. 
• They are known as suicide bags of a cell.
• By digesting worn-out organelles, food particles, and foreign substances in the cell, Lysosomes fulfil the job of cellular waste disposal.

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Types of Plant Cell

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Plant cells are eukaryotic cells found in species belonging to the Plant Kingdom. As an organism develops, its cells mature to the point where they can perform specialized activities. Plant cells include parenchyma cells, sclerenchyma cells, collenchyma cells, xylem cells, and phloem cells, among others. Let's take a closer look at the activities of these cells:

1. Xylem Cells: In vascular plants, xylem cells are transport cells. They aid in the transportation of water and nutrients from the roots to the leaves and other plant components.
2. Parenchyma Cells: In all plants, parenchyma cells perform an important role. Plants' live cells that are involved in the formation of leaves are known as chloroplasts. They also play a role in gas exchange, food generation, organic product storage, and cell metabolism. Because they are thinner, these cells are usually more flexible than others.
3. Phloem Cells: A sugar-carrying cell found throughout the plant, generated by the leaves. These cells survive for a long time after they have reached adulthood.
4. Collenchyma Cells: These cells are rugged as well, but not quite as sclerenchyma cells. They also help the plants develop while they are young. Their development is synchronized with the expansion and stretching of the facility.
5. Sclerenchyma Cells: This is due to the presence of a hardening chemical, which makes these cells stiffer than collenchyma cells. These cells are found in all plant roots and are primarily responsible for supporting the plants.

Types of Plant Tissue

Plant Cell Functions

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There are several functions of plant cells, including:

• Plant cells are the main building blocks of plants and carry out various mechanical and physical processes.
• Chloroplasts in the plant cells help in the process of photosynthesis.
• Photosynthesis is the biochemical process where the plants synthesize their own food with the help of sunlight, water and carbon dioxide.
• Plant cells provide a rigid shape and help them to stand erect by providing necessary structural stability.
• The Cell wall and Cell Membrane of plants regulate the flow of components to the cytoplasm and block any unwanted foreign pathogens.

Check out: How are water and minerals transported in plants?

Previous Year Questions

1. All types of plastids possess essentially the same structure because they … [NEET 1992]
2. Flagella of prokaryotic and eukaryotic cells differ in … [NEET 2004]
3. A cell organelle containing hydrolytic enzymes is … [NEET 2016]
4. Water soluble pigments found in plant cell vacuoles are … [NEET 2016]
5. Which of the following are not membrane-bound? … [NEET 2015]
6. Besides giving out secretory vesicles … [NEET 1994]

Things to Remember

• Plant cells are the basic building unit of all plant life.
• Plant cells are eukaryotic cells which means they have a true nucleus.
• Plant cells consist of a cell wall and a cell membrane which is not seen in animal cells.
• Plant cells also consist of chloroplast which helps in the process of photosynthesis.
• The primary function of the plant cell is photosynthesis.
• A plant cell is made up of a variety of components

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