A cell is the fundamental unit of life. It is a structural, functional, and biological unit of all living beings. It can replicate itself independently. They are known as the building blocks of life. Each one contains a fluid called the cytoplasm, which is enclosed by a membrane. Also present in the cytoplasm are several biomolecules like proteins, nucleic acids, and lipids.
Who Discovered Cell
The Cell was discovered by Robert Hooke in 1665. He observed a piece of bottle cork under a compound microscope and noticed minuscule structures that reminded him of small rooms. Consequently, he named these “rooms” as cells. However, his compound microscope had limited magnification, and hence, he could not see any details in the structure. Owing to this limitation, Hooke concluded that these were non-living entities. In 1883, Robert Brown, a Scottish botanist, provided the very first insights into the structure. He was able to describe the nucleus present in the cells of orchids.
Characteristics of Cells
- They provide structure and support to the body of an organism.
- The cell’s interior is organized into different individual organelles surrounded by a separate membrane.
- The nucleus holds genetic information necessary for reproduction and growth.
- Every room has one nucleus and membrane-bound organelles in the cytoplasm.
- Mitochondria, a double membrane-bound organelle is mainly responsible for the energy transactions vital for the survival of the room.
- Lysosomes digest unwanted materials in the cells.
- The endoplasmic reticulum plays a significant role in the internal organization of the cells by synthesizing selective molecules and processing, directing, and sorting them to their appropriate locations.
Types of Cells
Based on structure, there are 2 types:
Structure of Cell
The structure comprises individual components with specific functions essential to carry out life’s processes. These components include the cell wall, membrane, cytoplasm, nucleus, and organelles.
- Cell Membrane: It present in all the cells. It is the outer covering of a room within which all other organelles, such as the cytoplasm and nucleus, are enclosed. It is also referred to as the plasma membrane. By structure, it is a porous membrane that permits the movement of selective substances in and out of the cell. Besides this, the cell membrane also protects the cellular component from damage and leakage.
- Cell Wall: It is made up of cellulose, hemicellulose, and pectin. It is present exclusively in plant cells. It protects the plasma membrane and other cellular components. The cell wall is also the outermost layer of plant cells. It is a rigid and stiff structure surrounding the cell membrane. It provides shape and support to the cells and protects them from mechanical shocks and injuries.
- Cytoplasm: The cytoplasm is a thick, clear, jelly-like substance present inside the cell membrane. Most of the chemical reactions within a cell take place in this cytoplasm. The cell organelles such as the endoplasmic reticulum, vacuoles, mitochondria, ribosomes, are suspended in this cytoplasm.
- Nucleus: It contains the hereditary material of the cells, the DNA. It sends signals to the cells to grow, mature, divide and die. The nucleus is surrounded by the nuclear envelope that separates the DNA from the rest of the cells. The nucleus protects the DNA and is an integral component of a plant’s cell structure.
- Cell Organelles: They are composed of various cell organelles that perform certain specific functions to carry out life’s processes. The different cell’s organelles, along with their principal functions, are as follows:
Functions of Cells
Important functions are as follows:
- Facilitate Growth Mitosis.
- Allows Transport of Substances.
- Energy Production.
- Aids in Reproduction.
- Provides Support and Structure.