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Cells

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A cell is the basic fundamental essential unit of life. The discovery of cells from their essential construction to the elements of each and every cell organelle is called Cell Biology. Robert Hooke was the primary Biologist who found cells. All life forms are comprised of cells. They might be comprised of a single cell (unicellular), or numerous cells (multicellular).

Cell Definition:

It is the basic unit of life having all the essential components in it to survive such structure is known as the Cell.

What is a Cell?

A cell is the basic unit of life. It is first discovered by Robert Hooke. Studying cells is known as cell biology. Every living organism is made up of cells. The organism also can be classified into 2 types on the basis of no. of cells: If one cell is known as unicellular, if more than 2 cells then those organisms are known as multicellular.

The cell is the basic unit of an organism. The size, and shape can carry according to the function of that particular cell. The cell is a combination of different cell organelles which perform different functions. The cell is the lowest level of organization of any living organism.

Cell Structure

 

Discovery of Cell

Rober Hooke observe a cell for the first time in 1665. Robert Hooke was observing a dried segment of the bottle cork with a compound microscope. During the observation, he noticed various little chambers which he named the cells. Compound microscopes have limited magnification and can’t see the cell properly. With all his observations he stated that those chambers are non-living.

After some time another scientist- Anton Van Leeuwenhoek observe bottle cork under a compound microscope with more magnification. During his observation, he saw that cell showing some moments. Because of this, he stated that cells are living. 

Later Rober Brown was the first scientist to provide the cell structure and nucleus in an orchid cell.

Characteristic of Cells

Below are the following characteristics of a cell.

  • Cells help in the structure of an organism.
  • A cell is a membrane-bound organelle having other cell organelles which perform different functions
  • Nucleus present in the between of a cell. It carries all the genetic information of a cell.
  • Lysosomes an other cell organelles help in cellular digestion.
  • Cytoplasm is present in the interior of a cell in which all cell organelles rea present.

Types of Cells

There are two cell types depending on the cellular structure i.e., prokaryotes and eukaryotes

Prokaryotic Cell

Prokaryotic cells are normally single-celled and more primitive than eukaryotic cells. Prokaryotic cells are cells that don’t have a true nucleus. Instead of nuclei, they have nucleoids in which the genetic material of a cell is present. 

  • The genetic material either DNA or RNA
  • Pk cells don’t have membrane-bound organelles.
  • The size of pk cell carries form 0.1-0.5μm.
  • Pk cells reproduce via asexual mode i.e., binary fission, fragmentation, and sexual mode i.e. Conjugation.

Eukaryotic Cell

Eukaryotic cells are normally tracked down in multicellular creatures, yet there are a few single-celled eukaryotes. Eukaryotic cells have a true nucleus. An ek cell is a membranous structure having all the membrane-bound organelles embedded in the cytoplasm.

  • The size of Ek cell is 10-100μm
  • Ek cells include various types of organisms like -plants, fungi, protozoans, and animals.
  • Ek cells also reproduce via both sexual and asexual modes. 
  • The genetic material of ek mainly is DNA in some organisms it is RNA as well.

Also Read: Difference between Prokaryotic and Eukaryotic cell

Cell Structure

The cell structure includes individual parts with explicit capabilities fundamental for complete life’s cycles. These parts incorporate the cell wall, cell layer, cytoplasm, core, and cell organelles. 

Cell Membrane

  • The cell membrane upholds and safeguards the cell. It controls the development of substances all through the cells. It isolates the cell from the outer climate. The cell membrane is available in every one of the cells.
  • The cell membrane is the external covering of a cell inside which any remaining organelles, like the cytoplasm and nucleus, are encased. It is additionally alluded to as the plasma layer.
  • By structure, it is a permeable membrane (with pores) that allows the development of specific substances all through the cell. Other than this, the cell layer likewise shields the cell part from harm and leakage.
  • It frames the wall-like construction between two cells as well as between the cell and its environmental factors.
  • Plants are stationary, so their cell structures are very much adjusted to safeguard them from outer elements. The cell wall assists with building up this capability.

Cell Wall

  • The cell wall is the most unmistakable piece of the plant’s cell structure. It is comprised of cellulose, hemicellulose, and gelatin.
  • The cell wall is available only in plant cells. It protects the plasma membrane and other cell parts. The cell wall is likewise the peripheral layer of plant cells.
  • It is an inflexible and firm design encompassing the cell membrane.
  • It gives shape and backing to the cells and safeguards them from mechanical shocks and wounds.

Cytoplasm

  • The cytoplasm is a thick, clear, jam-like substance present inside the cell layer.
  • The vast majority of the synthetic responses inside a cell occur in this cytoplasm.
  • The cell organelles, for example, the endoplasmic reticulum, vacuoles, mitochondria, and ribosomes, are suspended in this cytoplasm.

Nuclear Core

  • The core contains the inherited material of the cell, the DNA.
  • It conveys messages to the cells to develop, mature, gap, and bite the dust.
  • The core is encircled by the nuclear envelope that isolates the DNA from the remaining of cell.
  • The core safeguards the DNA and is a fundamental part of a plant’s cell structure.

Cell Organelles

  • Nucleolus: The nucleolus is the site of the ribosome combination. Additionally, it is associated with controlling cell exercises and cell proliferation.
  • Nuclear layer: The nuclear layer safeguards the core by shaping a limit between the core and other cell organelles.
  • Chromosomes: Chromosomes assume a vital part in deciding the sex of a person. Every human cell contains 23 sets of chromosomes.
  • Endoplasmic Reticulum: The endoplasmic reticulum is engaged with the transportation of substances all through the cell. It assumes an essential part in the digestion of carbs, and the union of lipids, steroids, and proteins.
  • Golgi Bodies: Golgi bodies are known as the cell’s mailing station as it is associated with the transportation of materials inside the cell.
  • Ribosome: Ribosomes are the protein synthesizers of the cell.
  • Mitochondria: The mitochondrion is designated the “powerhouse of the cell.” It is called so on because it produces ATP – the cell’s energy cash.
  • Lysosomes: Lysosomes safeguard the cell by digesting the unfamiliar bodies entering the cell and helping in cell recharging. Consequently, they are known as the cell’s self-destruction.
  • Chloroplast: Chloroplasts are the essential organelles for photosynthesis. It contains a pigment called chlorophyll.
  • Vacuoles: Vacuoles store food, water, and other waste materials in the cell.

Cell Theory

The cell hypothesis expresses that the cell is the key primary and useful unit of living matter. In 1839 German physiologist Theodor Schwann and German botanist, cell theory states that:

  • All living organisms are made up of cell
  • The cell is the basic fundamental unit of life.
  • Omnis cellula-e-cellula i.e. cell is made from an existing cell.

Functions of a Cell

  • Structure and Support: Cells provide the structural basis of all organisms.
  • Growth: Cells are responsible for the growth of the organism.
  • Transport: Cells transport the nutrients that are used in the different chemical processes which take place inside them. As a result of these processes, a waste product is produced. Cells then work to get rid of this waste. In this manner, small molecules like such as oxygen, carbon dioxide, and ethanol pass through the cell membrane by diffusion. This method is known as passive transport. On the other hand, the larger molecules like the proteins and polysaccharides, go in and out of the cell via active transport.
  • Energy Production: Organisms need energy to perform different chemical reactions. In plants, the energy comes from the process of photosynthesis while in animals the energy comes via respiration.
  • Metabolism: The cell is responsible for the metabolism which includes all the chemical reactions that take place inside an organism to keep it alive.
  • Reproduction: A cell helps in reproduction through the processes of mitosis (in more evolved organisms) and meiosis.

FAQs on a Cell

Q1: What is a cell?

Answer: 

The cell is the basic unit of life and it mainly consists of the nucleus, cytoplasm, and cell membrane.

Q2: Who first named cells?

Answer:

Hooke is the first person who mentioned cells in his book Micrographia.

Q3: Why cells are important?

Answer: 

Cells are important because they provide shape and structure to all living organism on the earth


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Last Updated : 28 Mar, 2023
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