Every living thing in existence comprises a complex system of biotic components following their hierarchical system. A body consists of various organs, which are made up of tissues. These tissues are made up of what we also refer to as the fundamental unit of life – the cell.
Cells on their own are found in various shapes and sizes, and each type of cell has its own function to perform. They were discovered by Robert Hooke in the late 1660s, changing how modern biology is approached altogether.
This article will explore what plant cells are, the components they are made of, and each component’s very own function.
|Table of contents|
|What is a plant cell?|
|Types of plant cells|
What is a plant cell?
As the name suggests, plant cells are present in plants and are of different types depending on their function. Primarily, there are two types of cells – prokaryotic and eukaryotic.
The word prokaryotic translates to ‘before the nucleus,’ which suggests that these are the types of cells that had no nucleus present in them. In contrast, plant cells considered eukaryotic have a nucleus in them.
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The basic structure of the plant cell includes various smaller components called “cell organelles” enclosed in a cell wall. These organelles perform different functions and sustain life processes in an individual cell. Let us now move on to the different kinds of such cell organelles.
The cell walls are a rigid outer covering of the cell that encloses all the other cell organelles. These walls comprise four different components:
A cell wall’s formation is guided by microtubules made up of three layers – the primary layer, a middle layer called lamella, and the third layer.
The primary functions of a cell wall are:
- to provide essential structure and protection to a plant cell
- help filter out waste
- take in nutrition from outside.
The cell membrane is a semi-permeable membrane present in the cell wall. It is made up of thin layers of protein and fats. Since it is semi-permeable, it only allows certain and selected substances to pass through the cell wall. The waste of plant cells travels out of the cell itself through this membrane.
The cytoplasm is the cell organelle in which all the other components reside. It is made up of cytosol, a jelly-like fluid.
The nucleus is one of the most vital organelles in a plant cell. Since plant cells are eukaryotic, a nucleus is present as a membrane-bound structure inside the plant cell.
The nucleus carries out one of the most critical functions – storing DNA and genetic information required for cell division, metabolism, and development. Hence, it is often called the brain of the cells.
A nucleus consists of two major components:
- Nucleolus: responsible for manufacturing proteins and ribosomes
- Nucleopore: the nuclear membrane with perforations that helps in the transfer of proteins and nucleic acids.
These are the membrane-bound organelles that have their DNA. These plastids are essential to store starch and thus play an essential role in performing photosynthesis.
Plastids also produce essential molecules that are vital for a cell to function. They are of two types:
- Leucoplasts are present in non-photosynthetic plants
- Chloroplasts are present in photosynthetic plants.
Mitochondria are the double membraned cell organelle, often known as the powerhouse of a cell. They are responsible for producing adenosine triphosphate of ATP molecules. This compound gives energy to a cell to perform its vital life processes.
Ribosomes are often considered the minor membrane-bound cell organelles present in a plant cell. It mainly consists of RNA and protein. Since ribosomes manufacture proteins, they are often called the cell’s protein factory.
Lysosomes are the cell organelles responsible for storing digestive enzymes in enclosed membranes. They perform one of the most critical tasks in the plant cell by digesting worn-out cell organelles and single-handedly take care of the whole waste management part of the cell. They are often called suicidal bags of a cell.
The endoplasmic reticulum (ER) can be considered the highway inside a plant cell. Their function is to transport molecules produced by the cell to their designated location. Endoplasmic Reticulum is of two types:
- Smooth ER: No ribosomes attached to its surface
- Rough ER: Ribosomes are attached throughout their surface.
The cell often contains some crystalline structures. They can broadly be classified into two categories based on their structures-
- Druse Crystal: It comprises calcium oxalate monohydrate, a compound most frequently seen in kidney stones.
- Raphide Crystal: These are made up of the same compound, calcium oxalate but are needle-like and sharp information.
Chloroplast is the cell organelle responsible for photosynthesis and the storage of starch produced. In terms of its structure, it is an elongated cell organelle with a phospholipid enclosing.
Each chloroplast has a green colour pigment called chlorophyll, which is responsible for photosynthesis and gives a plant its signature green colour. This chlorophyll absorbs sunlight and converts it into energy, which is used to transform carbon dioxide and water into glucose.
Golgi apparatus or Golgi bodies are usually present in all the eukaryotic cells. This organelle is responsible for distributing the synthesized macromolecules to their designated locations in a plant cell.
The central vacuole is considered the most prominent cell organelle present in a plant cell, as it occupies nearly 1/3rd of the entire space in a plant cell body. The central vacuole is enclosed inside a membrane called tonoplast.
Apart from simply acting as a storage space for molecules in the plant cell, it is also responsible for maintaining the “Turgor pressure” inside a plant cell. This pressure is the plant’s outward force against the cell wall so that the plant cell does not implode under pressure created by the cell wall.
Types of plant cells
Plant cells are divided into various categories depending upon their function in a plant. As the plant matures, each cell gets a particular characteristic and function to adhere to.
For example, some cells might specialize in transporting food and water inside the plant, while others might act as protectors from external factors and situations. The plant cells are divided into 5 basic types, which are as follows:
- Collenchyma cells: These cells support the plants due to their rigid body structure. It also acts as a primary source of support when plants restrain growth and development due to the lack of a hardening agent.
- Parenchyma cells: The parenchyma cells play the most vital role in all the plants alike. These are the living parts of a plant involved in food production by photosynthesis, storage of organic products, cell metabolism, and, most importantly – the exchange of gases. Structurally, these cells are thinner and more flexible than other cells.
- Sclerenchyma cells: These are the rigid cells that provide protection and integrity to a plant and are often found in the outermost layer of the plant. They are rigid because of the presence of a hardening agent. They are also majorly found in the roots of a plant.
- Xylem cells: They are the transporting cells in a plant responsible for transporting water and minerals.
- Phloem cells: Like xylem cells, phloem cells also transport cells in a plant rather than transporting water and minerals. It transports the food produced by leaves to different parts of the plant.
Cells are the fundamental building blocks of anything that comes under the biotic sphere. They are of various kinds, based upon whether or not they have a nucleus present in them. Namely, Prokaryotic cells – where a nucleus is absent and Eukaryotic cells – where a functional nucleus is present.
All the plant cells are eukaryotic and necessary to perform bodily functions inside a plant required for survival.
The plant cells are made up of smaller cells called cell organelles, which have their unique structure, composition, and function. These cell organelles work together to perform life processes required for survival.
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1. What organelle would you not expect to see in an animal cell, and why do they require it?
The organelle chloroplast is found in plant cells but is absent in animal cells. It functions as a food processor because it contains chlorophyll (a substance that gives plants their signature green color), which turns sunlight and the energy from it into sugar or chemical energy that the plant may use in the future.
2. What is an organism?
When a group of cells comes together to create tissues, which subsequently form organs for certain functions, we end up with a system of function for all of the organs in a body, which is known as an organism.
3. Define prokaryotic unicellular organisms?
These organisms have the following characteristics:
- For Metabolism, use plenty of range materials, such as sulfur cellulose and ammonia.
- They are easily found in the environment.
- They are invisible to the naked eye.
- Bacteria and archaic bacteria, for example.
4. List some functions of the Plasma in a plant cell?
Here are a few of the many functions of plasma:
- It serves as a structural foundation.
- It acts as a material sender from the outside to the inside or the other way round, as receptor locations.
- It is a molecule transporter
- Provide identification marker information.
- Like hypotonic, isotonic, and hypertonic solutions, it causes “diffusion” of water and gases in both cells.
5. What is Cytoplasm?
The liquid that is present in a cell is termed cytoplasm. “Cyto” refers to “cell” and “plasma” refers to “liquid.” It’s made up of a combination of water, salt, and protein. Each of these components carries out a specific function for the cell. Their delicate fiber arrangement is a difficult scenario.
6. Identify the difference between a cell membrane and a cell wall?
The cell membrane is the fragile outer membrane. It regulates the flow of people in and out of the cell. A phospholipid bilayer, embedded proteins, and some carbohydrates make up the plasma membrane. Cell wall, on the other hand, is normally porous, non-living, and rather thick in plant cells, and is made up of cellulose, hemicellulose, and pectin, and serves to support and protect the membrane.
7. What role does the gas exchange reaction play in plants?
As a by-product of photosynthesis, molecular oxygen is produced, which is a significant supply of oxygen in the atmosphere for all living things on the planet. The hydrogen ions created in this way are used to reduce NADP to NADPH, a powerful reducing agent. When electrons released from PSII are transported to PS I via electron carriers, it forms a gradient for ATR synthesis.
8. How do photosynthesis and respiration relate to one other?
Photosynthesis obtains energy from solar light, whereas respiration requires the breakdown of glucose molecules to obtain energy in the form of ATP molecules. Both processes are mutually reliant. The final product of photosynthesis is used in respiration (glucose in the form of food). To make ATP (adenosine triphosphate) for energy. Carbon dioxide and water are released throughout the process, which photosynthesis uses to make additional sugars.