Cell: The Unit Of Life
The cell is the smallest, fundamental unit of life and is sometimes referred to as the "building block of life." It is the smallest unit that can perform all the functions necessary for life, such as metabolism, energy conversion, and reproduction. Some organisms are composed of a single cell, called unicellular organisms (like bacteria), while others are composed of many cells, called multicellular organisms (like human beings). Its study forms the foundational base of biology with its high weightage in the entrance exams like NEET, Paramedical, and Pharmacy.
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- What is a Cell?
- Cell and Its Organelles
- Characteristics of Cells
- Cell Theory
- Types of Cells
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Each cell is enclosed by a membrane and contains various structures (organelles) that perform specific tasks, having a division of labor. This article covers the cell and its organelles with unique features that allow cells to function effectively in living organisms. It covers both prokaryotic & eukaryotic cells and cell theory, which states that all living things are made of cells.
What is a Cell?
The most fundamental, structural, and functional unit of all living beings is the cell. A cell is a structure containing organelles that perform essential processes for the cell to survive. Not all cells, however, are the same. Cells are capable of self-sustaining existence and executing vital life tasks. All creatures, including plants and animals, are made up of one or more cells, each of which originates from a previous cell. Some of the basic essential information about cells is discussed below:
Cells can perform all the essential life activities such as growth metabolism and reproduction on their own.
Cells have different organelles responsible for different functions. These organs are the nucleus, mitochondria, ribosomes, and many others. Each one of them has its specific role to play inside our body.
According to the cell theory, cells come from pre-existing cells.
Unicellular organisms contain single cells while multicellular organisms have specialized cells working together for every mechanism taking place in the body.
The cell membrane is one of the important organelles present and responsible for the exchange of materials between the cell and its environment.
The genetic material of the cell is DNA which is present in the nucleus and has all the essential instructions for cellular functions and reproduction.
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Cell and Its Organelles
Each cell is enclosed by a membrane and contains various organelles, having a division of labor. Some organelles with their basic functions in the cell are given below:
Organelle | Basic Function |
It controls what enters and leaves the cell. | |
It has the DNA and controls cell activities. | |
It supports and holds organelles in place with its semi-fluid matrix. | |
Semi-autonomous organelles Mitochondria, Chloroplasts | Mitochondria provide energy to the cell in the form of ATP, and chloroplasts convert sunlight into energy (only in plant cells). |
The rough ER makes proteins, while the smooth ER makes lipids and detoxifies. | |
It packages and sends proteins and lipids around the cell. | |
It breaks down waste and unwanted materials. | |
It stores water and nutrients and helps maintain pressure in plant cells. | |
It helps in cell division. | |
It makes proteins for the cell. | |
It provides structure and protection to the cell (only in plant cells). |
Characteristics of Cells
Cells are the basic units of life, and they have several unique features that allow them to function effectively in living organisms. The following are some of the most important properties of cells:
Unique Feature | Description |
Ability to Perform Life Functions | Cells can carry out essential tasks like getting energy, growing, and reproducing. |
Uniqueness in Function | Each cell type has its own job, like muscle cells helping with movement or skin cells protecting the body. |
Independent Life for Some | Some organisms (like bacteria) live with just one cell that does everything needed to survive. |
Division into Tissues (Multicellular) | In bigger organisms, cells work together in groups (tissues) to do special jobs, like nerve or muscle tissues. |
Control Center and Protection | The membrane controls entry, the nucleus gives instructions, and the cytoplasm is where all the work happens. |
Cell Theory
Matthias Schleiden (1838) and Theodor Schwann (1839) together proposed the initial form of the cell theory, combining their findings. Even though Schleiden and Schwann proposed the hypothesis, numerous renowned scientists have added to it, upgrading it from a theory to a commonly acknowledged fact.
The cell theory is a fundamental scientific principle that states:
All living organisms are composed of one or more cells.
The cell is the basic structural and functional unit of life.
All cells arise from pre-existing cells.
Types of Cells
The cells can be comparable to factories in that they have various workers and departments working toward a shared goal. The different types of cells have different purposes. There are mainly two types of cells based on their cellular structure:
The basic difference between both types of cells is described below in the table:
Key Features | Prokaryotic cell | Eukaryotic cell |
Nucleus |
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Size |
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Complexity |
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Membrane bound Organelles |
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Cell division |
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Examples |
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Ribosomes |
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Cell Wall |
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Metabolism |
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DNA Structure |
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Frequently Asked Questions (FAQs)
A cell is the basic structural and functional unit of all living things.
In 1665, Robert Hooke discovered cells. Under a compound microscope, he examined a piece of cork and saw minute shapes resembling little apartments. As a result, he dubbed his discovery "cells."
The nucleus directs and regulates the cell's functions (such as development and metabolism) and houses the genes, which hold the cell's genetic information. Small entities found within the nucleus are known as nucleoli.
Mitochondria are referred to as the "powerhouse" of the cell since it produces cellular energy in the form of ATP (adenosine triphosphate).
The nucleus is called the master of the cell because it controls all the activities of the cell. It contains the cell's DNA, which has instructions for growth, function, and reproduction.
According to cell theory, all living entities are made up of cells and are products of cells. It also implies that all cells originate from pre-existing ones.
Cells are the fundamental units of life, capable of performing all of the metabolic activities that a typical cell needs to survive. All living species have the same basic requirements for survival. All living things must breathe, digest food to obtain energy, and eliminate metabolic waste. Cells are capable of completing all of the body's metabolic tasks. As a result, cells are referred to as the fundamental units of life.
The cell is called a structural and functional unit of life because it is the smallest unit which performs all the crucial functions of life. These mechanisms and functions are responsible for the building blocks of all living organisms.
Yes, Cell the unit of life is considered one of the most important chapters from the NEET perspective. It carries a weightage of 10 to 12% of the total marks.
DNA, Nucleus, Chromosomes, Mitochondria, ribosomes and cell evolution are important points from the cell unit of life.
Chloroplast is called the kitchen of the cell because it makes food for the plant through photosynthesis. It uses sunlight, carbon dioxide, and water to make glucose (food) and oxygen.
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