Cells-Cell: Structure and Functions

Introduction

The study of living beings is referred to as biology. Their diversity was highlighted by the comprehensive explanation of their form and looks. The cell theory highlights the unity that lies beneath this diversity of forms, namely the cellular organisation of all living things.

Whenever one observes living organisms, the very first question that probably comes to mind is what is the basic unit of structure and function of all living organisms. The cell is regarded as the basic unit of life or the basic unit of structure and function in living things.

The word “cell” came from the Latin word “cellus,” meaning “little room.” Over one trillion cells make up the human body. Because cells are specialised to execute distinct jobs, they vary in size and shape.

History

  1. Anton Van Leeuwenhoek invented the microscope, which enabled cell observation.
  2. In 1665, Robert Hooke examined a sample of cork under a microscope and discovered that it was made up of microscopic compartments that he named “cells.”
  3. Leeuwenhoek discovered bacteria, red blood corpuscles and sperms, all of which are cells, in 1672.
  4. In 1831, an Englishman named Robert Brown noticed that all cells had a centralized substance, which he named the nucleus.

The invention of the microscope made it feasible to recognise the cell as a structural unit of life. It is fascinating to study how the modern cell developed from discrete pieces to become a constituent of larger structures.

The Cell

Cells are the structural and functional units of life that make up all creatures. A cell is a unit of protoplasm that is connected by plasma or cell membrane and has a nucleus. The cytoplasm and nucleus are both made up of protoplasm, which is a soul component. Mitochondria, golgi bodies, ribosomes, endoplasmic reticulum, plastids and lysosomes are all organelles found in the cytoplasm.

Some creatures, such as bacteria, protozoans, and algae, have only one cell in their bodies. Higher animals, plants, and fungi, on the other hand, have many cells in their bodies; thus, called multicellular.

Structure of Prokaryotic and Eukaryotic Cells

Cytologists distinguish between two types of cells. Prokaryotes, including such bacteria, are organisms that lack a well-formed nucleus. Those others have a well-defined nucleus that is encircled by a nuclear membrane. They are eukaryotes or multicellular organisms.

Prokaryotic Cell

  1. Prokaryotes are among the world’s oldest living species, with fossil evidence reaching back nearly 3.5 billion years.
  2. These prokaryotes survived the earth’s prehistoric climate. Some relied on chemical energy, while others relied on solar energy. These extremophiles survived for millions of years and continued to evolve.
  3. The name “prokaryote” comes from the Greek words “pro,” which means “before,” and “karyon,” which means “kernel.” It literally means “before nuclei.”
  4. Eukaryotic cells tend to be larger and more complex than prokaryotic ones.
  5. Prokaryotic cells also have a distinctive characteristic: they do not contain membrane-bound organelles such as the nucleus. To reproduce, the mechanism of binary fission can be used.
  6. Prokaryotes have an outer capsule that wraps around the entire body. It acts as a protective layer. Avoiding phagocytosis is crucial.
  7. The pilus, a hair-like attachment found on the outside of prokaryotes, aids in organisms’ attachments to different environments. For the most part, the pilus resists being flushed. It is also known as the attachment pili. It is common in bacteria.
  8. Just beneath the outer covering is the cell wall. It provides rigidity and strength for the cell.
  9. One can find the cytoplasm deeper within the plasma membrane. It aids in cell growth.
  10. The cytoplasm contains ribosomes, which are vital for protein synthesis. It is also one of the smallest components of a cell.
  11. Mesosomes, which are unique formations found in some bacteria cells, aid with cellular respiration. Plasmids are small circular DNA fragments found in almost all prokaryotes.
  12. Flagella are used to assist mobility. However, pilus can also serve as a mobility aid. Prokaryotic organisms include bacteria and archaea.
  13. Additionally, each member of Kingdom Monera can be a prokaryote.

Eukaryotic cell

  1. The term “Eukaryotes” comes from the Greek words “eu,” which means “good,” and “karyon,” which means “kernel,” and so means “good or real nuclei.” Eukaryotes are relatively larger than prokaryotes. With the exception of Kingdom Monera, they encompass practically all of the major kingdoms.
  2. The cell wall of eukaryotes supports and protects the plasma membrane. The plasma membrane protects cells and regulates chemical flow.
  3. The nucleus contains DNA and can be used to protect all genetic information. The nuclear membrane surrounds the nucleus. The nuclear membrane surrounds the nucleus and plays a vital role in protein synthesis. Eukaryotic cells also contain mitochondria, which can produce energy later on.
  4. The photosynthetic subcellular sites of chloroplasts can only be found in plant cells. Material movement is assisted by the endoplasmic retina. There are many cell organelles that perform distinct functions, including lysosomes, ribosomes, mitochondria, golgi bodies, endoplasmic reticulum, vacuoles, centrioles and nucleus.
  5. Eukaryotes are nearly every unicellular organism that has a nucleus and all multicellular organisms.

Difference Between Prokaryotic And Eukaryotic Cells

These two types of cells may be completely different, but they share many similarities. Both have cell membranes and ribosomes. However, that is where the similarities end. This list includes all variations between prokaryotic-eukaryotic cells:

  1. The diameter of a prokaryotic cell varies from 0.1-5.0 micrometers, while the diameter of a eukaryotic cell extends from 10 μm to 100 μm.
  2. The prokaryotic cell is always single-celled, but the eukaryotic cell can be both single-celled and multi-celled.
  3. The cell organelles are absent in prokaryotic cells, but they are present in eukaryotic cells.
  4. Prokaryotic cells lack a nucleus, whereas eukaryotic cells have one. The nucleus of prokaryotic cells, on the other hand, is replaced by nucleoids.
  5. Prokaryotic cells lack mitochondria, whereas eukaryotic cells have them.
  6. Prokaryotic cells lack lysosomes and centrosomes, whereas eukaryotic cells have both.
  7. Prokaryotic cells lack the endoplasmic reticulum, whereas eukaryotic cells have it.
  8. Circular DNA is found in prokaryotic cells, whereas linear DNA is found in eukaryotic cells.
  9. In comparison to eukaryotic cells, prokaryotic cells have a smaller and more spherical ribosome. In most cases, the eukaryotic cell is linear.
  10. Prokaryotic cells, which are chemically complicated, usually have a cell wall. The cell wall, on the other hand, is simple in nature in eukaryotes if present.
  11. Flagella found in the prokaryotic cells is smaller than those seen in eukaryotic cells.
  12. Asexual reproduction occurs in prokaryotic cells, although both sexual and asexual reproduction occurs in eukaryotic cells.
  13. In prokaryotic cells, cell division occurs through binary fission, but in eukaryotic cells, cell division occurs through mitosis. 

Conclusion 

The cell structures are of different types in the different categories of organisms. The organism works with the help of cells present in the organism, the cells of different types within the difference in the structure are seen in the different organisms. The cells of the organisms have different functions including the production of energy as well as the transportation of the essential things for the organism to the different parts of the organism. Each cell of the organism has its own function in the development of the organism.

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