Cell Wall: Essential Structure for Efficient Cell Functions

The cell  has a basic structural organization. This helps the performance of the function of cell wall like respiration, obtaining nutrition, and clearing of waste material, or forming new proteins. This means that a particular function is carried out by a cluster of cells at a definite place in the body. This cluster of cells, called a tissue, is arranged and designed so as to give the highest possible efficiency of function. 

Information about Cell: Life’s Basic Building Block

• Discovery: Cells were first discovered by Robert Hooke in 1665. 
  • Cell is a Latin word for ‘a little room’. 
  • He observed the cells in a cork slice with the help of a primitive microscope.
  • In 1674, Leeuwenhoek used an advanced microscope to unveil free-living cells in pond water. 
  • Then, in 1831, Robert Brown identified the cell’s nucleus, while in 1839, Purkinje introduced the term ‘protoplasm’ for the cell’s fluid component.
• The Cell Theory ( Schleiden (1838) and Schwann (1839)):

• All the plants and animals are composed of cells and the cell is the basic unit of life.
• All cells arise from pre-existing cells , given by Virchow (1855).

• Unicellular Organisms: The discovery of magnifying lenses revealed the microscopic world, where a single cell can form an entire organism (e.g. Amoeba, Chlamydomonas, bacteria), known as unicellular organisms.
• Multicellular Organisms: Organisms such as fungi, plants, and animals, consist of cells working together in various body parts. 
  • All life begins as a single cell that divides to produce more cells, demonstrating that every cell comes from pre-existing cells.
• Shape and Size: Cell shape and size relate to their function of the cell wall, some, like Amoeba, exhibit changing shapes, while others have fixed, distinct shapes (e.g., nerve cells). 
• Functions: All living cells share fundamental functions. 
  • function of the cell wall efficiently due to division of labor, akin to multicellular organisms. 
• Organelles: They contain specialized components called cell organelles, each performing specific tasks such as material synthesis and waste removal.
  • These organelles collectively form the cell’s basic unit, and intriguingly, all cells, regardless of their function or organism, possess the same organelles.

 Cell Wall: The Structural and Functional Unit of Life

• Function of cell wall: Each living cell has the capacity to perform certain basic functions of the cell wall that are characteristic of all living forms. 
• Cell Organelles: The Cellular component is called Cell Organelles. 
  • Examples: plasma membrane, nucleus and cytoplasm. 
• A cell is able to live and perform all its function of the cell wall because of these organelles.
• These organelles together constitute the basic unit called the cell. 

• Under Microscope: If we study a cell under a microscope, we would find three features in almost every cell, plasma membrane, nucleus and cytoplasm. 
• Crucial Role: All activities inside the cell and interactions of the cell with its environment are possible due to these features.

Plasma Membrane Or Cell Membrane: The Dynamic Border of Life’s Essential Space

• Outermost Layer: This is the outermost covering of the cell that separates the contents of the cell from its external environment. 
  • The cell membrane is an active part of the cell.
• Selectively Permeable Membrane:  The plasma membrane allows or permits the entry and exit of some materials in and out of the cell. 
  • It also prevents movement of some other materials. 
  • The cell membrane, therefore, is called a selectively permeable membrane.
• Flexibility: The plasma membrane is flexible and is made up of organic molecules called lipids and proteins.

Plant Cell Armor: The Strength of Cellulose Protection

• Special Feature: Plant cells have another rigid outer covering called the cell wall. 
  • The cell wall lies outside the plasma membrane. 
• Composition: The plant cell wall is mainly composed of cellulose. 
  • Cellulose is a complex substance and provides structural strength to plants.
• Protective Layer: Cell walls permit the cells of plants, fungi and bacteria to withstand very dilute (hypotonic) external media without bursting. 

Nucleus:

• Discovery: It was Robert Brown in 1831 who discovered the nucleus in the cell. 
• Membrane: The nucleus has a double layered covering called a nuclear membrane.
• Chromosomes: The nucleus contains chromosomes, chromosomes contain information for inheritance of characters from parents to the next generation in the form of DNA (DeoxyriboNucleic Acid) molecules. 
  • Chromosomes are composed of DNA and protein. 
  • DNA molecules contain the information necessary for constructing and organizing cells. 
  • Functional segments of DNA are called genes.
• Central Role: The nucleus plays a central role in cellular reproduction.

• Advancement: Eventual advancements in science and technology shed more light into the cell, with new findings and discoveries about its structure and cellular components.  
• During the 1950s, scientists postulated the concept of prokaryotic cells and eukaryotic cells, with earlier groundwork being laid by Edouard Chatton, a French Biologist in 1925.

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