Structural Organization and Functional Symphony of Cell Organelles

The cell  has a basic structural organization involving various components, including cell organelles. This helps the cells to perform functions 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. 

Cell Organelles at Work: Exploring the Fluid Realm of Cytoplasm and Its Specialized Helpers 

• The cytoplasm is the fluid content inside the plasma membrane. 
• It also contains many specialized cell organelles. 
• Each of these organelles performs a specific function for the cell.

Cell Organelles: The Essential Builders of Cell Structure and Functionality 

• Large and complex cells need many chemical activities to support their structure and function. 
• To keep these activities separate from each other, these cells use membrane-bound organelles within themselves.
• Important example of cell organelles are: endoplasmic reticulum, Golgi apparatus, lysosomes, mitochondria and plastids.

Cell Organelles: Endoplasmic Reticulum’s Role in Cell Structure and Functions

• Structure: The endoplasmic reticulum (ER) is a large network of membrane-bound tubes and sheets, representing a crucial component among various cell organelles. 
  • It looks like long tubules or round or oblong bags (vesicles). 
  • The ER membrane is similar in structure to the plasma membrane.
• Types: There are two types of ER– rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER). 
• Functions:
  • The SER helps in the manufacture of fat molecules, or lipids. 
  • Act as Channel: The function of the ER is to serve as channels for the transport of materials (especially proteins) between various regions of the cytoplasm or between the cytoplasm and the nucleus.
  • Protein Synthesis: The ribosomes are the sites of protein manufacture. 
    • The manufactured proteins are then sent to various places in the cell depending on need, using the ER.
  • In the liver cells of the group of animals called vertebrates, SER plays a crucial role in detoxifying many poisons and drugs.
  • Framework: The ER also functions as a cytoplasmic framework providing a surface for some of the biochemical activities of the cell.

Golgi Apparatus: 

• It is a system of membrane-bound vesicles (flattened sacs) arranged approximately parallel to each other in stacks called cisterns.
• These membranes often have connections with the membranes of ER and therefore constitute another portion of a complex cellular membrane system.
• Function: 
  • Its functions include the storage, modification and packaging of products in vesicles.  
  • In some cases, complex sugars may be made from simple sugars in the Golgi apparatus.
  • The Golgi apparatus is also involved in the formation of lysosomes.

Lysosomes: 

• Lysosomes are membrane-bound sacs filled with digestive enzymes. These enzymes are made by RER.  
• Lysosomes are a kind of waste disposal system of the cell.
• Lysosomes are also known as the ‘suicide bags’ of a cell.

Mitochondria: 

• Powerhouse: Mitochondria are known as the powerhouses of the cell. 
• The energy required for various chemical activities needed for life is released by mitochondria in the form of ATP (Adenosine triphosphate) molecules. 
  • ATP is known as the energy currency of the cell. 
    • The body uses energy stored in ATP for making new chemical compounds and for mechanical work.
  • Mitochondria  have their own DNA and  ribosomes. Therefore, mitochondria are able to make some of their own proteins.

Plastids: 

• Plastids are present only in plant cells.
• There are two types of plastids – chromoplasts (coloured plastids) and leucoplasts (white or colorless plastids). 
  • Plastids too have their own DNA and ribosomes.
  • Chromoplasts containing the pigment chlorophyll are known as chloroplasts. 
    • Chloroplasts are important for photosynthesis in plants.
  • Leucoplasts are primarily organelles in which materials such as starch, oils and protein granules are stored.

Vacuoles: 

• Vacuoles are storage sacs for solid or liquid contents.  
  • Vacuoles are small sized in animal cells while plant cells have very large vacuoles.
  • The central vacuole of some plant cells may occupy 50-90% of the cell volume.
  • In plant cells vacuoles are full of cell sap and provide turgidity and rigidity to the cell.
  • In some unicellular organisms, specialized vacuoles also play important roles in expelling excess water and some wastes from the cell.

Cell Organelles at Work: Guiding the Division for Growth and Reproduction

• New cells are formed in organisms, powered by the orchestrated efforts of cell organelles, to support growth, replace old, dead and injured cells, and to form gametes required for reproduction.  
  • The process by which new cells are made is called cell division.
• Cell Organelles and Division:  There are two main types of cell division: mitosis and meiosis.
  • Mitosis : This is the process of cell division by which most of the cells divide for growth. 
    • In this process, each cell, called as the mother cell, divides to form two identical daughter cells. 
    • The daughter cells have the same number of chromosomes as the mother cell. 
    • It helps in growth and repair of tissues in organisms.
  • Meiosis : When a cell divides by meiosis it produces four new cells instead of just two.

 The new cells only have half the number of chromosomes than that of the mother cells.

Conclusion
Cell organelles play a crucial role in orchestrating mitosis and meiosis, ensuring accurate genetic transmission. From the endoplasmic reticulum’s structural support to mitochondria’s energy production, cell organelles actively contribute to essential cellular functions. Their collaboration underscores the intricate precision within the microscopic realm of cell division.

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