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When we look around our surroundings we observe a variety of organisms. Not only us, even on the surface of the skin or inside your digestive or organ tract, but a huge number of different microorganisms also reside there. This is how we are home to approximately 100 trillion bacterial cells and structures.
We can infer that our body is acting as an ecosystem.
The surroundings and nature consist of both prokaryotic and eukaryotic cells.
All the cellular structures can be categorised into these two broad segments. The domains- Bacteria and Archaea (consists of unicellular organisms) are put under prokaryotes. The term ‘Pro’ refers to ‘before’ and ‘Kary’ refers to the ‘nucleus’. Eukaryotes are animals, protists, fungi and plants. The word ‘EU’ refers to true.
PROKARYOTIC CELLS AND EUKARYOTIC CELL
According to the classification of the two-empire system described in the studies of Édouard Chatton, the prokaryotic cells were segmented within the empire Prokaryotic. On the other hand, the three-domain system that is based on the concept of molecular analysis classifies the prokaryotes into two broad parts: Bacteria/ or the Eubacteria and Archaea/ or the Archaebacteria). The Organisms that possess nuclei are placed in a third segment called Eukaryota. It is believed that the prokaryotic cells have arisen before the eukaryotic cell as per the theories of the origin of life.
Examples of Eukaryotes include animals, fungi, animals, protists and plants.
Examples of Prokaryotes include Bacteria/ or Eubacteria and Archaea/ or archaebacteria. Cyanobacteria/Blue-green algae (BGA), Myxobacteria.
DIFFERENCE BETWEEN PROKARYOTIC AND EUKARYOTIC CELLS
Robert Hooke, an English scientist in the year 1665, led to the discovery of the cell
Some varieties of cells may not have membrane-bound organelles while in some they might be present. According to the classification based on the internal structure and composition of the cell, two types of cells are observed in an organism called the Eukaryotic cell and Prokaryotic cells.
Given below are the key differences between prokaryotic and eukaryotic cells. The distinguishing features are based on the presence or absence of membrane-bound organelles, encasement by a nuclear envelope is absent or present etc.
BASED ON – CELL SIZE
Most prokaryotes zone between 1 µm and 10 µm, but variations of around 0.2 µm (in Mycoplasma genitalium) to 750 µm (in Thiomargarita namibiensis).
The size of prokaryotic cells is around 0.1- 5.0 um (micrometres).
The size of a eukaryotic cell is around 5-100 um (micrometre).
BASED ON THE PRESENCE OR ABSENCE OF MEMBRANE-BOUND AND NON-MEMBRANE-BOUND ORGANELLES
1. NUCLEUS
The Prokaryotes are devoid of a nucleus whereas the eukaryotes have a nucleus that is bounded by a membrane.
2. LYSOSOME
It is absent in a prokaryotic cell
It is present in eukaryotic cell
3. PEROXISOME
Absent in prokaryotic cell
Present in eukaryotic cell
4. MICROTUBULES
It is absent in a prokaryotic cell
It is present in eukaryotic cell
5. ENDOPLASMIC RETICULUM (ER)
Ths endoplasmic reticulum organelle is absent in a prokaryotic cell whereas the ER is present in a eukaryotic cell.
6. MITOCHONDRIA
Also called the powerhouse of the cell, it is absent in prokaryotic cells whereas present in eukaryotic cells.
7. GOLGI APPARATUS
The Golgi apparatus is absent in a prokaryotic cell
It is present in eukaryotic cell
8. VACUOLES
The vacuoles are absent in prokaryotic cells and present in eukaryotes.
BASED ON – THE SITE WHERE THE PROCESS OF TRANSCRIPTION TAKES PLACE
In a eukaryotic cell, the process of transcription takes place inside the cytoplasm chamber.
In prokaryotic cells, the process of transcription takes place in the interior of the nucleus.
BASED ON – TYPE OF REPRODUCTION
The process of sexual reproduction is absent in prokaryotic cells whereas in the eukaryotic cell sexual reproduction is the means of generation of offspring.
BASED ON – THE CELL NUMBER THEY ARE COMPOSED OF
Prokaryotic cells are usually unicellular (single-celled) in nature whereas eukaryotic cells are multicellular i.e. having more than one cell.
BASED ON THE TYPE OF RIBOSOME THEY POSSESS
Ribosomes are composed of subunits that are named as the sedimentation coefficient described in Svedberg units (S).
It shows the correlation between the applied acceleration that leads to sedimentation and the speed of sedimentation of a particle.
Ribosomes are the molecular factories where there is a synthesis of proteins.
- The ribosomes of prokaryotic cells have ribosomes having a sedimentation coefficient of 70S. It can be divided further into two subunits:
The L subunit/ largest subunit: Includes a 50S sedimentation coefficient, plus 31 proteins, 5S and 23S rRNA.
The minor subunit (S subunit): It has a 30S sedimentation coefficient and contains 16S rRNA and 21 proteins.
- The ribosomes of eukaryotic cells have ribosomes with a sedimentation coefficient of the 80S. It can be divided further into two subunits:
The L subunit/ largest subunit Includes a sedimentation coefficient of the 60S consisting of 48 proteins and 28S 5S 5.8S rRNA.
The minor subunit includes a 40S sedimentation coefficient and comprises 33 proteins and a single 18S rRNA molecule.
CONCLUSION
The surroundings and nature consist of both prokaryotic and eukaryotic cells.
All the cellular structures can be categorised into these two broad segments. The domains- Bacteria and Archaea (consists of unicellular organisms) are put under prokaryotes. The term ‘Pro’ refers to ‘before’ and ‘Kary’ refers to the ‘nucleus’. Eukaryotes are animals, protists, fungi and plants. The word ‘EU’ refers to true eukaryotes. The differences are drawn based on the various structural and compositional features of both.
