The Fundamental Unit of Life

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02 Prokaryotic Cell and Eukaryotic Cell

  • The concept of prokaryotic cell and eukaryotic cell was created by scientists during the 1950s.
  • These cells have two basic features: the cell membrane and a plasma membrane.
  • While prokaryotes are unicellular in nature, few single cell and all multicellular organisms are known as Eukaryotes.
  • They have the cytoplasm and genetic material in common.
  • Prokaryotes are made of a single cell like bacteria and archaea.

Prokaryotic cells:

  • It is derived from a Greek word meaning before nuclei.
  • Prokaryotic cells are simpler and smaller and do not possess nucleus or other cell organelles.
  • Prokaryotic cell is present in those organisms that belong to the kingdom Monera.
  • The outside of the wall is covered by a capsule and cell wall which provides strength and rigidity.
  • Cytoplasm helps in cellular growth and a plasma membrane contain proteins, etc.
  • The cytoplasm region contains ribosomes which are the smallest part and are essential for protein synthesis, mesosomes or the folding that help in cellular respirations, plasmids the small circle of DNA, pili, and flagella.
  • They reproduce through nuclear fission.

Eukaryotic Cells:

  • It is also derived from a Greek word meaning good or true nuclei.
  • They include all life kingdoms except monera.
  • Eukaryotic cells are complex and larger than the prokaryotic cells.
  • They consist of the cell wall which protects and supports the plasma membrane that surrounds the cell and controls the entry and exit of certain substances.
  • The nucleus contains DNA that stores all information and is surrounded by nuclear membrane.
  • Nucleolusplays a vital role in protein synthesis.
  • Ribosome is composed of proteins, Golgi bodies, lysosomes, vacuoles, cytoplasm, chromosomes, and centrosomes.
  • Endoplasmic reticulum helps in movement of materials.
  • Mitochondria are involved in performing their cellular functions.
  • Chloroplast is the subcellular sites of photosynthesis.

Differences between prokaryotic cells and eukaryotic cells:

Prokaryotic cell Eukaryotic cell
Size of a prokaryotic cell is generally small ( 1 - 10 mm ). Size of a eukaryotic cell is generally large ( 5 -100 mm )
Cell wall is usually present and is chemicall complex in nature. Cell wall when present is chemically simple in nature.
Nucleus is absent  i.e. Nuclear region or nucleoid is not surrounded by a nuclear membrane Nucleus is present i.e. Nuclear material is surrounded by a nuclear membrane.
These cells consist of ribosomes which are smaller in size and circular in shape when compared to the cells of eukaryotes. The ribosomes of eukaryotes are larger in size and are linear in shape.
DNA arrangement is circular in shape. DNA arrangement is linear in shape.
Mitochondria are absent. Mitochondria are present.
The cytoplasm in prokaryotes does not contain the endoplasmic reticulum. In this, the cytoplasm has the endoplasmic reticulum
Plasmids are present in prokaryotes. Plasmids are very rarely found in eukaryotes.
These have small ribosomes. These have large ribosomes.
In this, the lysosome, mesosome, and centrosome are absent. Mesosome, Lysosomes, and centrosomes are usually present in Eukaryotes.
The flagella is smaller in size in prokaryotes The flagella is larger in size in case of eukaryotes
It contains single chromosome. It contains more than one chromosome.
Nucleolus is absent. Nucleolus is present.
Membrane bound cell organelles are absent. Membrane bound cell organelles such as mitochondria, plastids, endoplasmic reticulum, Golgi appreatus, lysosomes, peroxisomes,etc, are present.
Cell division occurs by fission or budding (no mitosis). Cell division occurs by mitotic or meiotic cell division.
Reproduction takes place asexually. Reproduction takes place both asexually and sexually.
Ex. Bacteria and Archaea Ex. Plant and animal cell

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