You all must be knowing cells are the most fundamental units present in any living organism. They combine to build tissues, which later combine to make an organ. Cells are the only thing that keeps all of us alive. Whether the species is animals or humans or plants or even bacteria, millions and billions of cells are present in every organism living in this world.
In this informative article, we will be discussing plant cells in particular and have a deep understanding of all their related concepts.
Plant cell – Definition
Plant cells are considered eukaryotic cells. This can be found with a nucleus and a specialized feature known as organelles capable of doing several functions. Like plant cells, animal cells contain a nucleus whose organelles are also similar. One of the main features of a plant cell is a cell wall in it, which gives a distinct shape to the cell.
Plant cell – Diagram
When comparing a plant cell to an animal cell, it is larger and is rectangular. Plant cells are very different though they share a few cell organelles because they are highly capable of performing distinct functions.
These cells can only be viewed using a microscope because they are too tiny for our naked eye to notice. They are of micro shape. Following is the schematic representation of a typical plant cell:
Plant cell diagram (Reference – Byju’s website)
Cell wall
The cell wall can be seen as a rigid layer composed of hemicellulose, cellulose, pectin, lignin, glycoproteins, etc. The cell wall is situated outside of the membrane of the cell. It consists of cellulose, proteins and polysaccharides.
Furthermore, the cell wall’s primary function would be to protect the cell. Apart from that, it also helps in providing structure and shape to the cell. It further provides strength and support to the cell against any mechanical actions such as stress or an external force is applied to it. Cell walls filter the molecules passing around the cells, in and out.
Microtubules assist the cell wall informing around the cell, and it contains three layers, middle, primary and secondary lamella. The primary cell wall formation is done with the help of cellulose, which is surrounded by enzymes.
Cell membrane
Within the cell wall, there presents a semi-permeable membrane. This can be composed of thin layers of fat and protein in it. The cell membrane has a vital part within the cell as it controls the entry and exit of several substances.
For example, it keeps away toxins and ensures that they will not enter while minerals and nutrients are being transported across.
Nucleus
The nucleus is found in eukaryotic cells and is considered to have a membrane-bound structure. The nucleus plays a vital role in storing DNA and other information related to hereditary senses needed for metabolism, cell division and growth. The following are the two subdivided functions of the nucleus:
- Nucleopore:
Nucleopore is capable of allowing nucleic acids and proteins to pass through them. These are nothing but the nuclear membrane allocated with holes.
Nucleolus produces protein-producing structures as well as ribosomes of the cell.
Plastids
Plastids are presented with their DNA, and their organelles are regarded as membrane-bound. These are essential to store starch and perform the photosynthesis process.
Plastids help synthesise various molecules. These molecules are capable of forming the building blocks of the cell. Given below are a few functions and features of some plastids:
Chromoplasts:
Chromoplasts are coloured plastids and are heterogeneous. Chromoplasts play a vital role in storing eukaryotic organisms and are highly responsible for pigment synthesis. They contain yellow, orange and red coloured pigments that could give colour to all the flowers and ripe fruits.
Chloroplasts:
Chloroplasts are shaped like a disc and are seen as elongated organelles covered by phospholipid membranes. The stroma is the fluid present inside the chloroplast, which contains circular DNA.
A green coloured pigment is contained within each chloroplast, essential for the photosynthesis process. The sole purpose of chlorophyll is to absorb light energy from the sun. After doing so, it utilises the sunlight to transform water and carbon dioxide into oxygen and glucose.
Leucoplasts:
These leucoplasts are being discovered in the non-photosynthetic tissues of plants. Leucoplasts help store starch, lipid and protein.
Mitochondria
Mitochondria are regarded as the double membraned organelles that are being discovered in all the eukaryotic cells’ cytoplasm. Mitochondria are capable of providing energy by separating sugar molecules and carbon dioxide. Therefore, mitochondria are also called the powerhouse of the cell.
Ribosomes
Ribosomes are the smallest membrane-bound organelles. They consist of protein and RNA. Ribosomes are referred to as protein factories of the cell because they are the major sites of the protein.
Lysosome
Lysosomes are capable of holding digestive enzymes. This is done in an enclosed membrane. Lysosomes help perform waste disposal activities. This can be done by digesting the organelles that are worn out, foreign bodies, food particles, etc., in the cell.
Golgi apparatus
Golgi apparatus can help distribute synthesised macromolecules to several other cell parts. These apparatus are being found in the eukaryotic cells.
Central Vacuole
The central vacuole can occupy around 30 % of the volume of the cell in a grown plant. The central vacuole is surrounded by a membrane called tonoplast. Additionally, other than storage, the vital role of this vacuole is to maintain turgor pressure on the cell wall. Cell sap has been contained in the central vacuole. This can be regarded as a mix of enzymes, salts, and other substances.
Plant Cell Types
After the plants are matured, their cells become specialized to perform various essential functions for their survival. Some plant cells store food, while others transport water and other nutrients.
Mentioned below are some of the various plant cell types:
Xylem cells:
In vascular plants, these cells are regarded as transport cells. Xylem cells are capable of helping in the transportation of water and minerals straight from roots up to the leaves and other parts of the plants.
Phloem cells:
These cells are also termed transport cells, as they transport food prepared by the leaves. The food is then being transferred to various parts of the plants.
Parenchyma cells:
These cells perform a vital role in all plants. They are considered living cells of plants and play a significant role in producing leaves. Parenchyma cells seem to be involved in food production, organic product storage, exchange of gases and metabolism of cells. These are thinner in size and are more flexible compared to other cells.
Sclerenchyma cells:
Due to the presence of hardening agents in this cell, these can be found a little bit rigid. The sclerenchyma cells can be typically discovered in all the roots of the plants. Their main purpose is to support the plants.
Collenchyma cells:
Collenchyma can be determined as rigid cells. They play a fundamental role in providing support to the plants. This is when the growth is restrained because of the shortage of hardening agents on the walls.
Functions of plant cells
- Cells are considered the building blocks of plants. The process of photosynthesis is the major function performed by plants. The occurrence of photosynthesis is on the plant’s chloroplasts. Photosynthesis is nothing but a process done by plants to produce food.
- It involves sunlight, water and carbon dioxide to generate oxygen and glucose. This is how light energy is being converted into chemical energy.
- Some plant cells help prepare food, while others produce water and essential nutrients.
Also SEE: Explanation of Plant Cell
